research article thin-film lscs based on pmma nanohybrid...

$: Research Article Thin-Film LSCs Based on PMMA Nanohybrid ...downloads.hindawi.com/journals/ijp/2013/235875.pdf · Refractive index Design 1 Design 2 [Nano-SiO 2] (wt%) F : E ect of$
Hindawi Publishing CorporationInternational Journal of PhotoenergyVolume 2013 Article ID 235875 10 pageshttpdxdoiorg1011552013235875

Research ArticleThin-Film LSCs Based on PMMA Nanohybrid CoatingsDevice Optimization and Outdoor Performance

S M El-Bashir12 O A AlHarbi1 and M S AlSalhi1

1 Department of Physics and Astronomy Science College King Saud University Riyadh 11451 Saudi Arabia2Department of Physics Faculty of Science Benha University Benha 13518 Egypt

Correspondence should be addressed to S M El-Bashir elbashiregyahoocom

Received 19 August 2013 Accepted 23 September 2013

Academic Editor Maria da Graca P Neves

Copyright copy 2013 S M El-Bashir et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This study concerns the design optimization of thin-film luminescent solar concentrators (TLSCs) based on polymethylmethacry-late (PMMA)silica nanohybrid films doped with coumarin dyestuffs specialized in coloring plastics Two designs of TLSCs hadbeen prepared and characterizedThe first consists of a transparent nanohybrid layer coated on a fluorescent PMMA substrateThesecond design is the ordinary configuration in which fluorescent nanohybrid layer is coated on a transparent PMMA substrateTheinvestigation of the spectral properties and efficiency parameters recommended the best solar energy conversion efficiency for thesecond design The outdoor performance of optimized TLSC was also evaluated under clear sky conditions of Riyadh city and thehourly values of the optical efficiency 120578opt were calculated for one year The best performance was achieved in summer since theshort circuit current for PV cell was doubled after being attached to TLSC and the value of 120578opt reached 40 which is higher thanother values recorded before due to the abundant solar energy potential in the Arabian Peninsula

1 Introduction

Concentrating sunlight is considered an important way todecrease the cost of photovoltaic (PV) energy conversionsince the cost of PV cell can be reduced by using concentratedsunlight on a smaller area Luminescent solar concentrators(LSCs) were firstly proposed in the late 1970s as an alternativeto the traditional focusing concentrators such as mirrors andlenses [1ndash4] LSC consists of a transparent plate with a highrefractive index (eg asymp149 for PMMA) doped with centersas shown in Figure 1When the incident light on the surface ofLSC is absorbed by the luminescent centers and isotropicallyreemitted over all the angles a fraction of light (asymp75 forPMMA) is internally reflected within the plate and guidedtowards the edges where small photovoltaic (PV) cells canbe placed to convert the concentrated light into electricity[5] Diffuse reflecting paints can be placed on the nonusededges in order to improve light collection and geometricalgain which is defined as the fraction between surface andedge areas of LSC [6] Since the collection of light is enhancedby total internal reflection diffused sunlight has a higher

probability of being collected and concentrated on PV cell Asa consequence LSCs do not require light tracking systemswhich represent an important and expensive component ofconventional concentrating systems [7] The interest of LSCresearch has recently been renewed due to the improvementin the stability of luminescent dyes and the development ofnew luminescent species such as quantum dots and inorganicalternative luminescent species [8] This paper deals withthe problems which hampered the development of LSCssuch as the stability of luminescent organic dyes and thematrix configuration [9] The first problem can be solved byusing fluorescent dyes specialized in engineering plastics suchas MACROLEX fluorescent dyes (Bayer Germany) thesedyes have been reported to have a promising thermal andphotostability in LSC applications [10] The second problemcan be faced by thin-film LSC configuration (TLSC) shownin Figure 2 which was proposed to reduce the reabsorptionof fluorescent photons and scattering losses TLSC devicesconsist of a 015 to 1mm thick layer of luminescent materialdeposited in a thicker transparent substrate (asymp30mm) ideallyof the same refractive index [11] Heavily doped luminescent

2 International Journal of Photoenergy

Cones of loss

Absorption orreabsorption

Transmitted

Absorption

dPhotovoltaic

cell

ReflectedDiffused

Figure 1 The operation principle of luminescent solar concentration (LSC)

Design (1)

PV cellLuminescent dye molecule

(a)

Design (2)

(b)

Figure 2 Outline of the fabricated TLSC designs

species can be doped in a transparent thin film and placedon a highly transparent substrate having the same refractiveindex for optical matching [12] This configuration offersthe possibility of reducing reabsorption effects by confiningall the absorption and fluorescence to the thin film whiletrapping and reflection events occur primarily in the clearmatrix [13] TLSCs have several other advantages as theyallow the stacking of the plates containing different typesof luminescent species to utilize full solar spectrum [14] Inaddition they reduce the fabrication cost as thin dopedmate-rial is sufficient for allowing for more flexible employmentsof thin films with appropriate optical properties on any hostsubstrate [15]

In the present study we aimed to optimize the efficiencyparameters of TLSCs by proposing two designs as depictedin Figure 2 Design (1) consists of a high refractive indextransparent PMMA nanohybrid layer coated on a fluorescentPMMA substrate Design (2) represents the ordinary design

in which the luminescent dye is dissolved in PMMA nanohy-brid layer then coated on a transparent PMMA substrate aspreviously described A detailed characterization of the spec-troscopic properties of the two designs will be presented by aseries of measurements in order to identify the predominatelosses limiting the efficiency parameters of TLSCs

2 Experimental

21 Preparation of LSC Matrices Hydrophilic nanosilica(SiO2Aldrich S5130 powder 7 nm) was freed from adsorbed

moisture by placing in an electric oven at 100plusmn5∘Candweigh-ing each hour until two consecutive weights are the sameAfter that PMMA (Aldrich MW 350 k) hydrophilic nanosil-ica and red coumarin dyestuff (MACROLEX FluorescentRed G Bayer) were mixed separately in chloroform (CHCl

3)

Transparent PMMA substrates were prepared by pouring

International Journal of Photoenergy 3

Excitation

Fluorescence

Front surface detection (FSD)

(a)

Excitation

Edge detection (ED)

Fluorescence

(b)

Figure 3 Excitation and detection arrangements of TLSC samples (a) Front surface detection (FSD) (b) edge detection (ED)

PMMACHCl3solution in a rectangular glass mold applying

the same procedure fluorescent PMMA substrates wereprepared by doping PMMACHCl

3solution with 200 ppm

coumarin dyestuff After that the dyed PMMA substrateswere cut in dimensions 4 times 1 times 03 cm3 and then coatedwith PMMASiO

2nanohybrids Two groups for LSC designs

were prepared The first group (design 1) consists of fluores-cent PMMA substrates coated by transparent PMMASiO

2

nanohybridwith nanosilica concentrations ranging from005to 1 wt The second group (design 2) consists of transpar-ent PMMA substrates coated by fluorescent PMMASiO

2

nanohybridwith nanosilica concentrations ranging from005to 1 wt and all doped with 200 ppm coumarin dyestuff Allthe hybrid solutions were sonicated for 6 hrs before pouringon the as prepared substrates and spin coated in a centrifugeat 2000 rpm for 1min to obtain uniform film coverage [10]then they were left to dry in an electric oven at 40∘C for 6 hrsThe film thicknesses were measured using a profilometer(Talystep Taylor Hobson UK) on a scratch made immedi-ately after deposition of five independent measurements [16]on each sample and found to be in the range of 50 plusmn 10 120583m

22 Measurements The absorption spectra of the hybridfilms were recorded in the wavelength range (200ndash900 nm)by a UV-VIS spectrophotometer (UNICAM Helios CoGermany) Steady-state fluorescence spectra were recordedin the wavelength range (400ndash800 nm) using a spectrofluo-rometer (SCHIMADZURF-5301 PC Japan) the spectra wererecorded for two sample arrangements shown in Figure 3The refractive index was measured by means of Abbe refrac-tometer (ATAGO1212NAR-1T SOLID Japan)TheoptimizedLSC sample was chosen to manufacture a prototype foroutdoor testing with dimensions of 20 times 8 times 03 cm3 A singlecrystalline silicon photodiode (PB X61 Siemens Germany)was used as a PV cell and attached to one narrow edge asshown in Figure 2(b)The other LSC edges were painted witha diffuse reflecting paint which has a diffuse reflectance value

of about 98 (Kodak Japan) LSC prototype was mountedhorizontally and testedmonthly for one year (2011) under daylight illumination on the roof of a building about (8m) highat Riyadh city (37∘N)The output short circuit current of LSCattached PV cell (119868Lsc) was measured along with that of thereference PV cell (119868rc) by using an accurate digital multimeter(PeakTech Germany) Besides the global solar radiation wasmeasured using a digital solar powermeter (Lutron SPM-1116SD Taiwan)

3 Results and Discussion

31 UV-Vis Optical Absorption Spectroscopy Figure 4 showsthe effect of nanosilica concentration on the UV-Vis absorp-tion spectra for design (1) LSCs in the wavelength range(200ndash900 nm) which is a distinctive spectra PMMA dopedwith organic laser dyes [17 18] A sharp increase of theabsorption in the UVA band has been observed by increas-ing nanosilica concentration this absorption is correspond-ing to 120587 minus 120587lowast transition of carbonyl groups in PMMAmacromolecules [19] It is observed that this increase isaccompanied with a remarkable distortion and broadeningin the absorption tail which is a consequence of a higherlevel of disorder of the polymer chains after bonding C=Ogroup with Si-OH group Considering the absorption bandobserved in the visible region around 520 nm character-izing S

119900rarr S

1transition of the dye molecules there

is no major change observed in the absorption value dueto the isolation of the dye molecules in PMMA matrixThe observed hyperchromic effect in the absorption spectrabeyond 600 nm of design (1) samples can be attributedto the decrease of the sample transmission by increasingnanosilica concentration to about 79 of that of pure PMMAas clarified by the inset in Figure 4 This can be due tothe light scattering by nanosilica aggregates as a result ofthe molecular bonding of silica nanoparticles with eachother


200 300 400 500 600 700 800 90000

02

04

06

08

10

12

14

00 02 04 06 08 1070

75

80

85

90

95

Abso

rban

ce

Wavelength (nm)

T (

)

[Nano-SiO2] (wt)

Incr

easin

g na

no-S

iO2

Figure 4 Effect of nanosilica concentration on the absorption andtransmission (inset) spectra of design (1) TLSCs

200 300 400 500 600 700 800 90000

04

08

12

16

00 02 04 06 08 1088

90

92

94

Abso

rban

ce

Wavelength (nm)

Incr

easin

g na

no-S

iO2

T (

)

[Nano-SiO2] (wt)


On the other hand for design (2) samples Figure 5illustrates that there are no significant changes observedin the absorption edge but there is an obvious increase inthe dye absorption due to the chemisorption of coumarinmolecules on the surface of silica nanoparticles throughhydrogen bonding with surface silanol groups [20] Thisbonding permits uniform dispersion of the dye moleculesin undersized cores formed by PMMASiO

2cages of the

hybrid PMMASiO2network and subsequently decrease the

probability of dye dimerization [21] As shown by the insetin Figure 5 the sample transmission is observed to reach

00 02 04 06 08 10

150

156

162

168

174

180

Refr

activ

e ind

ex

Design 1Design 2

[Nano-SiO2] (wt)

Figure 6 Effect of nanosilica concentration on the refractive indexof TLSC designs

about 94 of that for pure PMMA by increasing nanosilicaconcentration up to 1 wt this indicates the advantage ofthis configuration for improving LSC transmission Thisimprovement can be attributed to the fact that the inclusionof dye molecules in PMMASiO

2nanohybrids reduced the

probability of nanosilica aggregate formation that occurs athigh concentrations [22]

32 Refractive Index and Photon Trapping Efficiency Thedependence of the refractive index ldquo119899rdquo on the nanosilicaconcentration was studied for all the prepared samples ofTLSC designs as shown in Figure 6 A remarkable increase isnoted in the refractive index values for design (2) than thosefor design (1) TLSC samples This can be attributed to therole played by coumarin dyemolecules in reducing the aggre-gation of hydrophilic nanosilica in PMMASiO

2nanohybrid

film as confirmed by optical absorption spectroscopic mea-surements It has been reasoned that the nanohybrid coatingfilms for design (2) TLSC samples have more orientedstructure than design (1) TLSC samples and consequentlyincreased values of refractive index [23]

Photon trapping efficiency 120578trap was calculated from therefractive index 119899 of the films using the following equation[24]

120578trap = radic1 minus1

1198992 (1)

The effect of nanosilica concentration on the values of120578trap can be observed in Table 1 it is clear that the valuesof 120578trap for design (1) TLSC samples are lower than those ofdesign (2)This disadvantage is expectedwhendoping the dye


Table 1 The effect of nanosilica concentration on the efficiency parameters () 120578trap 120578120593 and 120578stok for all TLSC designs

Concentration (wt) Design (1) Design (2)120578trap 120578

120593120578stok 120578trap 120578

120593120578stok

0 749 237 862 740 231 879005 754 239 862 773 258 88201 759 240 862 785 377 88302 765 243 862 799 418 88703 767 245 862 802 431 88704 770 246 862 803 446 88705 774 249 863 805 512 88706 779 254 863 807 581 88707 784 257 863 809 678 88608 786 259 863 812 772 88609 791 265 863 817 853 8861 803 271 8626 821 910 900

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)

Incr

easin

g na

no-S

iO2

(a)

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)In

crea

sing

nano

-SiO

2

(b)

Figure 7 The effect of nanosilica concentration on the fluorescence spectra for (a) design (1) and (b) design (2) TLSCs

molecules in bulk plate due to the scattering of fluorescentradiation by aggregated dye molecules bulk matrix defectsand self-absorption effects [25]

33 Fluorescence Spectroscopy Figure 7 shows the effectof nanosilica concentration on the fluorescence spectra ofthe prepared TLSC designs measured by using FSD Fordesign (1) it is observed that the fluorescence intensity isincreased by increasing nanosilica concentration withoutany considerable change in the peak position this can beascribed to the increase of the number of fluorescent photonstrapped in the LSC matrix The shoulder that appearedin the spectra at higher nanosilica concentration may becorrelated with the scattering of the trapped emitted photonswith the matrix defects causing the resultant broadening

of fluorescence spectra [26] The same behavior is observedfor design (2) TLSCs with the exception of a remarkableblue shifted fluorescence and steadiness of the peak shapeeven at higher nanosilica concentrations This can be dueto two factors the first is the isolation of the dye moleculesby increasing nanosilica concentration causing blue shiftedfluorescence [27] and the second is the increase of the fractionof trapped fluorescent radiation due to the increase of therefractive index and consequently increase of the trappedfluorescence intensity The fluorescence quantum yield 120578

120601

has been calculated relative to a reference solution preparedfrom Rhodamine 101 (120578

120601119903= 1 in H

2O 001 HCL) using the

following relation [28]

120578120601= 120578120601119903(119863119904

119863119903

)(119899119904

119899119903

)

2

(1 minus 10

minusOD119903

1 minus 10minusOD119904) (2)


where 119863 is the integrated area under the corrected fluores-cence spectra 119899 is the refractive index and OD is the opticaldensity for the sample and reference Besides the Stokesefficiency which represents the energy loss by Stokes shiftwas calculated as the ratio between the absorption and flu-orescence maxima of dye molecules (120578stok = 120582abs120582em) [29]the values of 120578

120601and 120578stok are listed in Table 1 It is obviously

noted that the values of 120578120601and 120578stok for design (1) TLSCs

are lower than those of design (2) this can be explainedby the following Design (1) stands for PMMA matrix withlarge cores in which the dye molecules are just physicallyincorporated at high dye concentrations the dye moleculeshave a large tendency to be aggregated in these cores and formexcited state dimers (excimers) which are weakly fluorescent[30] On the other hand the calculated values of 120578

120601and 120578stok

for design (2) demonstrate that the dye molecules are shownto have a relatively uniform dispersion in undersized coresformed by PMMASiO

2cages of the hybrid PMMASiO

2

network These solid cages have increased the separationbetween the dyemolecules from each other and consequentlythe LSC coating can be heavily doped with high dye concen-trations without quenching monomer (single dye molecule)fluorescence [31] In view of the fact that the rotations andrelaxations of the electrons in the excited state of organic laserdyes are one of the main modes of the nonradiative energylosses PMMASiO

2nanohybrid is a suitable matrix which

reduces the internal rotational modes of the dye moleculescompared to the relatively flexible organic polymermolecules[32]

34 Efficiency Parameters for Solar Energy Conversion Forthe development of useful LSCs it is important to usephotostable dyes with a high overall dye efficiency 120578dye givenby [33]

120578dye = 120578abs120578120601120578stok120578self (3)

where 120578abs is the fraction of solar energy absorbed thatdepends on the absorption coefficient ldquo120572rdquo of the dye and theLSC thickness ldquo119889rdquo (120578abs = 1 minus 10

minus120572119889) [34] and 120578self accounts

for the effect of the reabsorption of emitted photons on thelight transport to the concentrator edge calculated from [35]

120578self =1198750

1 minus (1 minus 1198750120578120601120578trap)

(4)

where 1198750is the probability that an emitted the photon will

reach the edge without suffering self-absorption calculatedfrom

1198750=int1198751015840(120592) 119864 (120592) 119889120592

int119864 (120592) 119889120592 (5)

where the integrals 1198751015840(V)119864(V)119889V and 119864(V)119889V represent theareas under the fluorescence-wavenumber curves obtainedfrom edge fluorescence detected by (ED) and front surfacefluorescence (FSD) respectively measured as depicted byFigure 3 the obtained spectra is plotted in Figure 8 as arepresentative behavior for all samples The dependence of

12 13 14 15 16 17 18 19Wavenumber (103cmminus1)

Fluo

resc

ence

inte

nsity

(au

)

FSDED

Figure 8 A representative plot of the wavenumber dependence ofedge detected (ED) and front surface fluorescence (FSD) detectingfluorescence spectra measured for design (1) TLSC sample dopedwith 1 wt nanosilica

Design 1Design 2

00 02 04 06 08 10

65

70

75

80

85

90

95

100

[Nano-SiO2] (wt)

120578 self

()

Figure 9 The dependence of self-absorption efficiency 120578self onnanosilica concentration for TLSC designs

self-absorption efficiency 120578self on nanosilica concentrationis illustrated in Figure 9 it is obviously noted that design(1) TLSCs have low values of 120578self accompanied by irregularchanges by increasing nanosilica concentration On the otherhand the behavior of 120578self for design (2) exhibits a noticeablereduced self-absorption effect and scattering losses since thegain of the pathlength in the LSC substrate is compensated bythe loss within the optically dense film [36]


Design (1)

025

020

015

010

005

000

Effici

ency

()

Concentration ()

120578abs

120578dye

120578Conv

10

08

06

04

02

00

(a)

Design (2)

Effici

ency

()

Concentration ()120578abs

120578dye

120578Conv

08

07

06

05

04

03

02

01

0010

08

06

04

0200

(b)

Figure 10 Effect of nanosilica concentration on the efficiency parameters of TLSC designs

According to the photon flow diagram in LSCs theconversion efficiency of the LSC 120578conv which is defined asthe ratio of the number of fluorescent photons ldquo119873rdquo availablein the LSC to the number of the incident solar photons ldquo119873

119900rdquo

can be defined as [37]

120578conv = (1 minus 119877119891) 120578trap120578abs120578120601 =119873

119873119900

(6)

where (1 minus 119877119891) is the fraction of incident sunlight that is

collected by the surface and calculated fromFresnel reflection119877119891= (119899 minus 1)

2(119899 + 1)

2The effect of nanosilica concentration on the efficiency

parameters 120578abs 120578dye and 120578conv is illustrated in Figure 10 Forthe prepared TLSC designs it is clear that design (2) sampleshave higher efficiency parameters compared to design (1)samplesThehighest increase in the efficiency parameterswasachieved for design (2) TLSC doped with 1 wt nanosilicaconcentration which is increased to 3 10 and 11 times thanthose of design (1) TLSC for 120578abs 120578dye and 120578conv respectivelyIt is also observed that for the two designs the values of120578dye and 120578conv have the same behavior of 120578abs with varyingnanosilica concentrationThis reveals the advantage of design(2) in increasing the fraction of absorbed sunlight andenhancing solar energy conversion by TLSCs The highestcalculated values of conversion efficiency for the preparedTLSC designs had allowed the choice of design (2) (120578conv =55) to be tested outdoors for electrical conversion of solarenergy

35 Field Performance of TLSC The average daily solarinsolation on a horizontal surface 119875

119866was measured hourly

for one year (Riyadh 2011) and plotted as shown in Figure 11It is noticed that the curve of global solar radiation versus day

6 8 10 12 14 16 18 2000

02

04

06

08

10

Solar time (h)

WinterSpring

SummerAutumn

PG

(kW

m2)

Figure 11 The hourly distribution of the global solar energyradiation in Riyadh city over the year 2011

hours has reached its maximum value at the solar noon forall seasons with a highest value equal to 1 kWm2 achievedin summer This data is important for the properly design ofsolar energy system [38] and provides a good evaluation ofthermal environmentwithin buildings in hot countries whichis characterized by its extremely hot weather


4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)

Figure 12The average values of the short circuit current density 119869scover the year 2011

Figure 12 illustrates the average values of the short circuitcurrent density 119869sc over the year 2011 for the PV cell attachedto the TLSC edge mounted horizontally as shown in Figure 2It is noted that themaximumvalues of 119869sc are obtained aroundthe solar noon of each season due to the increase of directsolar radiation at this time The area under the 119869sc-solar timecurves is obtained and plotted in comparison with that of areference PV cell for all seasons as shown in Figure 13 It isclear that the maximum value of the obtained electric chargeby TLSC is obtained in summer (621 Ccm2) This value ismore than twice that recorded for horizontal bulk plate LSCin Benha city (Egypt) due to the fact that Riyadh city enjoyshigher solar insolation [39] This high amount of global solarenergy inRiyadh compared toBenha is caused by the increaseof the direct component due to the variations in solar altitudeand the zenith angle On the other hand it is noted that theminimum value of electric charge (162Ccm2) is obtained inspring due to the vagaries of the weather and the spread ofdust and clouds at this time of the year

The performance of the investigated TLSC was evaluatedunder clear sky conditions and the hourly values of theoptical efficiency 120578opt were calculated for all seasons using thefollowing equation [40]

120578opt = (119868sc119868ref)(119861

119866) (7)

where 119868sc and 119868rc are the short circuit currents of the PV cellsattached to TLSC edge and the reference PV cells directlyexposed to sunlight respectively 119866 is the geometric gaindefined as the ratio of the surface area to the edge area ofthe TLSC plate and 119861 is the ratio of PV cell response at

Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )

Figure 13The area under the 119869sc-solar time curves obtained of TLSCand plotted in comparison with that of a reference PV cell for allseasons (Riyadh-2011)

the fluorescence wavelength to the corresponding responseof solar spectra

Figure 14 demonstrates a plot of the hourly values of 120578optfor the investigated TLSC and the seasonal average values of120578opt and 119868sc119868ref are listed in Table 2 From the plot it is clearthat the yearly average value of 120578opt increases at the middayto a stationary value for 8 hrs then decreases near both thesunrise and sunset in contrast to the previously publishedwork [41 42]This can be due to the fact thatmost of the solarradiation in Riyadh is direct due to its high altitude anglesince the global solar radiation falling on a horizontal surfaceis given by [43]

119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863

is the diffused solar radiation 119875119861is the direct

(beam) component and 120574 is the solar altitude angle of thelocation The decrease of the yearly average value of 120578opt nearthe sunset and sunrise can be attributed to low amount ofdiffused radiation as a result of the high clearness index 119870

119879

in Riyadh [44] at most of the year months according to thefollowing equation [45 46]

119875119863

119875119866

= 1 minus 113119870119879 (9)

Furthermore Table 2 shows that summer average value of120578opt is nearly double that published for horizontal bulk LSCin Egypt (2361) This can be attributed to the advantage ofTLSCs in reducing the parasitic losses due to self-absorptionand scattering frommatrix impurities than bulk LSCs besidesthe abundant solar energy potential in the Arabian Peninsula[47]


6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()

Figure 14 The hourly distribution of the optical efficiency 120578opt forTLSC (Riyadh-2011)

Table 2 The average values of 120578opt and 119868sc119868ref for horizontallymounted TLSC for one year (Riyadh 2011)

Season 120578opt 119868sc119868ref

Winter 3140 1744Spring 3610 2005Summer 4028 2240Autumn 3821 2123Yearly average 3682 2045

4 Conclusions

Two designs of TLSCs have been prepared and characterizedin order to optimize the efficiency parameters and outdoorperformance The study of UV-Vis absorption indicated thatall the prepared samples of TLSC designs utilize a broadsection of the solar spectrum In addition calculated valuesof efficiency parameters suggested that design (2) is moreadvantageous since it has the lowest reabsorption possibilityof escape cone losses and the highest conversion efficiencyThe study of outdoor performance of the optimized design (2)TLSC showed the maximum recorded value of 120578opt (asymp40)Regarding the above-mentioned facts it can be stated thatdesign (2) TLSCs are potential candidates for solar energyconversion the in the Arabian Peninsula Further studiesof the molecular and photostability tests had to be donesince the second design is expected to show a distinctivephotostability due to the existence of the dye moleculesin the lower PMMA substrate protected by PMMA-SiO

2

nanohybrid coating which is considered as an effectivesolution for blocking harmful UV radiation Thus the low

efficiency of the second TLSC design could be compensatedby their application in large areas especially in the vast desertareas of hot countries which need conversion systems withenhanced photostability

Acknowledgment

This research project was supported by a grant from theResearch Center of the Female Scientific and Medical Col-leges Deanship of Scientific Research King Saud University

References

[1] W H Weber and J Lambe ldquoLuminescent greenhouse collectorfor solar radiationrdquo Applied Optics vol 15 no 10 pp 2299ndash2300 1976

[2] J S Batchelder A H Zewail and T Cole ldquoLuminescentsolar concentrators 1 theory of operation and techniques forperformance evaluationrdquo Applied Optics vol 18 no 18 pp3090ndash3110 1979

[3] A Goetzberger and W Greube ldquoSolar energy conversion withfluorescent collectorsrdquo Applied Physics vol 14 no 2 pp 123ndash139 1977

[4] R Reisfeld ldquoFuture technological applications of rare-earth-doped materialsrdquo Journal of The Less-Common Metals vol 93no 2 pp 243ndash251 1983

[5] M G Debije ldquoSolar energy collectors with tunable transmis-sionrdquo Advanced Functional Materials vol 20 no 9 pp 1498ndash1502 2010

[6] W G J H M van Sark ldquoLuminescent solar concentrators alow cost photovoltaics alternativerdquo Renewable Energy vol 49pp 207ndash210 2013

[7] A Goetzberger ldquoFluorescent solar energy collectors operatingconditions with diffuse lightrdquo Applied Physics vol 16 no 4 pp399ndash404 1978

[8] J Bomm A Buchtemann A J Chatten et al ldquoFabrication andfull characterization of state-of-the-art quantum dot lumines-cent solar concentratorsrdquo Solar EnergyMaterials and Solar Cellsvol 95 no 8 pp 2087ndash2094 2011

[9] B C Rowan L R Wilson and B S Richards ldquoAdvancedmaterial concepts for luminescent solar concentratorsrdquo IEEEJournal on Selected Topics in Quantum Electronics vol 14 no5 pp 1312ndash1322 2008

[10] S M El-Bashir F M Barakat and M S AlSalhi ldquoMetal-enhanced fluorescence of mixed coumarin dyes by silver andgold nanoparticles towards plasmonic thin-film luminescentsolar concentratorrdquo Journal of Luminescence vol 143 pp 43ndash492013

[11] J W E Wiegman and E Van der Kolk ldquoBuilding integratedthin film luminescent solar concentrators detailed efficiencycharacterization and light transport modellingrdquo Solar EnergyMaterials and Solar Cells vol 103 pp 41ndash47 2012

[12] G Griffini L Brambilla M Levi M D Zoppo and S TurrildquoPhoto-degradation of a perylene-based organic luminescentsolar concentrator molecular aspects and device implicationsrdquoSolar Energy Materials amd Solar Cells vol 111 pp 41ndash48 2013

[13] P T M Albers C W M Bastiaansen and M G Debije ldquoDualwaveguide patterned luminescent solar concentratorsrdquo SolarEnergy vol 95 pp 216ndash223 2013

[14] A A Earp G B Smith J Franklin and P Swift ldquoOptimisationof a three-colour luminescent solar concentrator daylighting


systemrdquo Solar Energy Materials and Solar Cells vol 84 no 1ndash4 pp 411ndash426 2004

[15] R Reisfeld ldquoNew developments in luminescence for solarenergy utilizationrdquoOptical Materials vol 32 pp 850ndash865 2010

[16] A Pepe PGallianoMAparicio ADuran and S Cere ldquoSol-gelcoatings on carbon steel electrochemical evaluationrdquo Surfaceand Coatings Technology vol 200 no 11 pp 3486ndash3491 2006

[17] A F Mansour M G El-Shaarawy S M El-Bashir M KEl-Mansy and M Hammam ldquoOptical study of perylene dyedopedpoly(methyl methacrylate) as fluorescent solar collectorrdquoPolymer International vol 51 no 5 pp 393ndash397 2002

[18] D Avnir D Levy and R Reisfeld ldquoThe nature of the silica cageas reflected by spectral changes and enhanced photostability oftrapped rhodamine 6Grdquo Journal of Physical Chemistry vol 88no 24 pp 5956ndash5959 1984

[19] M Hammam M K El-Mansy S M El-Bashir and M G El-Shaarawy ldquoPerformance evaluation of thin-film solar concen-trators for greenhouse applicationsrdquo Desalination vol 209 no1ndash3 pp 244ndash250 2007

[20] Y Huang X Y Ma G Z Liang and H X Yan ldquoInteractionsin organic rectorite composite gel polymer electrolyterdquo ClayMinerals vol 42 no 4 pp 463ndash470 2007

[21] D Levy R Reisfeld and D Avnir ldquoFluorescence ofEuropium(III) trapped in silica gel-glass as a probe forcation binding and for changes in cage symmetry during geldehydrationrdquo Chemical Physics Letters vol 109 pp 593ndash5971984

[22] R Reisfeld N Manor and D Avnir ldquoTransparent high surfacearea porous supports as new materials for luminescent solarconcentratorsrdquo Solar Energy Materials vol 8 no 4 pp 399ndash409 1983

[23] V Svorcık O Lyutakov and I Huttel ldquoThickness dependenceof refractive index and optical gap of PMMA layers preparedunder electrical fieldrdquo Journal of Materials Science vol 19 no 4pp 363ndash367 2008

[24] J Roncali and F Garnier ldquoPhoton-transport properties ofluminescent solar concentrators analysis and optimizationrdquoApplied Optics vol 23 no 16 pp 2809ndash2817 1984

[25] R W Olson R F Loring and M D Fayer ldquoLuminescent solarcon-centrators and the reabsorption problemrdquo Applied Opticsvol 20 no 17 pp 2934ndash2939 1981

[26] S A Ahmed Z Zang K M Yoo M A Ali and R R AlfanoldquoEffect of multiple light scattering and self-absorption on thefluorescence and excitation spectra of dyes in random mediardquoApplied Optics vol 33 no 13 pp 2746ndash2750 1994

[27] K Unger Porous Silica Elsevier New York NY USA 1979[28] S Fery-Forgues and D Lavabre ldquoAre fluorescence quantum

yields so tricky to measure A demonstration using familiarstationery productsrdquo Journal of Chemical Education vol 76 no9 pp 1260ndash1264 1999

[29] F P Shafer Dye Lasers Springer New York NY USA 1990[30] J F Rabek Experimental Methods in Polymer Chemistry John

Wiley amp Sons New York NY USA 1980[31] A M Hermann ldquoLuminescent solar concentratorsmdasha reviewrdquo

Solar Energy vol 29 no 4 pp 323ndash329 1982[32] S M El-Bashir ldquoPhotophysical properties of fluorescent

PMMASiO2nanohybrids for solar energy applicationsrdquo Jour-

nal of Luminescence vol 132 no 7 pp 1786ndash1791 2012[33] F Vollmer and W Rettig ldquoFluorescence loss mechanism due

to large-amplitude motions in derivatives of 221015840-bipyridyl

exhibiting excited-state intramolecular proton transfer andperspectives of luminescence solar concentratorsrdquo Journal ofPhotochemistry and Photobiology A vol 95 no 2 pp 143ndash1551996

[34] S M El-Bashir Photophysical Properties of PMMA Nanohy-brids and Their Applications Luminescent Solar Concentratorsamp Smart Greenhouses Book Project LAMPERT AcademicPublishing 2012

[35] J M Drake M L Lesiecki J Sansregret and W R L ThomasldquoOrganic dyes in PMMA in a planar luminescent solar collectora performance evaluationrdquo Applied Optics vol 21 no 16 pp2945ndash2952 1982

[36] A Hinsch A Zastrow and V Wittwer ldquoSol-gel glasses anew material for solar fluorescent planar concentratorsrdquo SolarEnergy Materials vol 21 no 2-3 pp 151ndash164 1990


[38] TMarkvart Solar Electricity JohnWielyamp Sons NewYorkNYUSA 1994

[39] M S Al-Ayed A M Al-Dhafiri and M B Mahfoodh ldquoGlobaldirect and diffuse solar irradiance in Riyadh Saudi ArabiardquoRenewable Energy vol 14 no 1ndash4 pp 249ndash254 1998

[40] M S De Cardona M Carracosa F Meseguer F Cusso and FJaque ldquoOutdoor evaluation of luminescent solar concentratorprototypesrdquo Applied Optics vol 24 no 13 pp 2028ndash2032 1985

[41] A F Mansour M G El-Shaarawy S M El-Bashir M KEl-Mansy and M Hammam ldquoA qualitative study and fieldperformance for a fluorescent solar collectorrdquo Polymer Testingvol 21 no 3 pp 277ndash281 2002

[42] M G El-Shaarawy S M El-Bashir M Hammam and M KEl-Mansy ldquoBent fluorescent solar concentrators (BFSCs) spec-troscopy stability and outdoor performancerdquo Current AppliedPhysics vol 7 no 6 pp 643ndash649 2007

[43] M Iqbal An Introduction to Solar Radiation Academic PressNew York NY USA 1983

[44] A Z Sahin A Aksakal and R Kahraman ldquoSolar radiationavailability in the northeastern region of Saudi Arabiardquo EnergySources vol 22 no 10 pp 859ndash864 2000

[45] K Ulgen ldquoOptimum tilt angle for solar collectorsrdquo EnergySources A vol 28 no 13 pp 1171ndash1180 2006

[46] E O Falayi A B Rabiu and R O Teliat ldquoCorrelations toestimate monthly mean of daily diffuse solar radiation in someselected cities in NigeriardquoAdvances in Applied Science Researchvol 2 no 4 pp 480ndash490 2011

[47] Z Aljarboua ldquoThe national energy strategy for Saudi ArabiardquoWorld Academy of Science Engineering and Technology vol 57pp 501ndash510 2009

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


Cones of loss

Absorption orreabsorption

Transmitted

Absorption

dPhotovoltaic

cell

ReflectedDiffused

Figure 1 The operation principle of luminescent solar concentration (LSC)

Design (1)

PV cellLuminescent dye molecule

(a)

Design (2)

(b)

Figure 2 Outline of the fabricated TLSC designs

species can be doped in a transparent thin film and placedon a highly transparent substrate having the same refractiveindex for optical matching [12] This configuration offersthe possibility of reducing reabsorption effects by confiningall the absorption and fluorescence to the thin film whiletrapping and reflection events occur primarily in the clearmatrix [13] TLSCs have several other advantages as theyallow the stacking of the plates containing different typesof luminescent species to utilize full solar spectrum [14] Inaddition they reduce the fabrication cost as thin dopedmate-rial is sufficient for allowing for more flexible employmentsof thin films with appropriate optical properties on any hostsubstrate [15]

In the present study we aimed to optimize the efficiencyparameters of TLSCs by proposing two designs as depictedin Figure 2 Design (1) consists of a high refractive indextransparent PMMA nanohybrid layer coated on a fluorescentPMMA substrate Design (2) represents the ordinary design

in which the luminescent dye is dissolved in PMMA nanohy-brid layer then coated on a transparent PMMA substrate aspreviously described A detailed characterization of the spec-troscopic properties of the two designs will be presented by aseries of measurements in order to identify the predominatelosses limiting the efficiency parameters of TLSCs

2 Experimental

21 Preparation of LSC Matrices Hydrophilic nanosilica(SiO2Aldrich S5130 powder 7 nm) was freed from adsorbed

moisture by placing in an electric oven at 100plusmn5∘Candweigh-ing each hour until two consecutive weights are the sameAfter that PMMA (Aldrich MW 350 k) hydrophilic nanosil-ica and red coumarin dyestuff (MACROLEX FluorescentRed G Bayer) were mixed separately in chloroform (CHCl

3)

Transparent PMMA substrates were prepared by pouring


Excitation

Fluorescence


(a)

Excitation

Edge detection (ED)

Fluorescence

(b)








2


2






119900rarr S




200 300 400 500 600 700 800 90000

02

04

06

08

10

12

14

00 02 04 06 08 1070

75

80

85

90

95

Abso

rban

ce

Wavelength (nm)

T (

)

[Nano-SiO2] (wt)

Incr

easin

g na

no-S

iO2


200 300 400 500 600 700 800 90000

04

08

12

16

00 02 04 06 08 1088

90

92

94

Abso

rban

ce

Wavelength (nm)

Incr

easin

g na

no-S

iO2

T (

)

[Nano-SiO2] (wt)



2cages of the



00 02 04 06 08 10

150

156

162

168

174

180

Refr

activ

e ind

ex

Design 1Design 2

[Nano-SiO2] (wt)






2nanohybrid




1198992 (1)





120593120578stok 120578trap 120578

120593120578stok

0 749 237 862 740 231 879005 754 239 862 773 258 88201 759 240 862 785 377 88302 765 243 862 799 418 88703 767 245 862 802 431 88704 770 246 862 803 446 88705 774 249 863 805 512 88706 779 254 863 807 581 88707 784 257 863 809 678 88608 786 259 863 812 772 88609 791 265 863 817 853 8861 803 271 8626 821 910 900

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)

Incr

easin

g na

no-S

iO2

(a)

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)In

crea

sing

nano

-SiO

2

(b)





120601


120601119903= 1 in H



120578120601= 120578120601119903(119863119904

119863119903

)(119899119904

119899119903

)

2

(1 minus 10

minusOD119903







120601and 120578stok



2





120578dye = 120578abs120578120601120578stok120578self (3)




120578self =1198750

1 minus (1 minus 1198750120578120601120578trap)

(4)



1198750=int1198751015840(120592) 119864 (120592) 119889120592

int119864 (120592) 119889120592 (5)



Fluo

resc

ence

inte

nsity

(au

)

FSDED


Design 1Design 2

00 02 04 06 08 10

65

70

75

80

85

90

95

100

[Nano-SiO2] (wt)

120578 self

()




Design (1)

025

020

015

010

005

000

Effici

ency

()

Concentration ()

120578abs

120578dye

120578Conv

10

08

06

04

02

00

(a)

Design (2)

Effici

ency

()


120578dye

120578Conv

08

07

06

05

04

03

02

01

0010

08

06

04

0200

(b)



119900rdquo



119873119900

(6)



2(119899 + 1)






6 8 10 12 14 16 18 2000

02

04

06

08

10

Solar time (h)

WinterSpring

SummerAutumn

PG

(kW

m2)




4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)




120578opt = (119868sc119868ref)(119861

119866) (7)


Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )




119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863



119879


119875119863

119875119866

= 1 minus 113119870119879 (9)



6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Excitation

Fluorescence


(a)

Excitation

Edge detection (ED)

Fluorescence

(b)








2


2






119900rarr S




200 300 400 500 600 700 800 90000

02

04

06

08

10

12

14

00 02 04 06 08 1070

75

80

85

90

95

Abso

rban

ce

Wavelength (nm)

T (

)

[Nano-SiO2] (wt)

Incr

easin

g na

no-S

iO2


200 300 400 500 600 700 800 90000

04

08

12

16

00 02 04 06 08 1088

90

92

94

Abso

rban

ce

Wavelength (nm)

Incr

easin

g na

no-S

iO2

T (

)

[Nano-SiO2] (wt)



2cages of the



00 02 04 06 08 10

150

156

162

168

174

180

Refr

activ

e ind

ex

Design 1Design 2

[Nano-SiO2] (wt)






2nanohybrid




1198992 (1)





120593120578stok 120578trap 120578

120593120578stok

0 749 237 862 740 231 879005 754 239 862 773 258 88201 759 240 862 785 377 88302 765 243 862 799 418 88703 767 245 862 802 431 88704 770 246 862 803 446 88705 774 249 863 805 512 88706 779 254 863 807 581 88707 784 257 863 809 678 88608 786 259 863 812 772 88609 791 265 863 817 853 8861 803 271 8626 821 910 900

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)

Incr

easin

g na

no-S

iO2

(a)

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)In

crea

sing

nano

-SiO

2

(b)





120601


120601119903= 1 in H



120578120601= 120578120601119903(119863119904

119863119903

)(119899119904

119899119903

)

2

(1 minus 10

minusOD119903







120601and 120578stok



2





120578dye = 120578abs120578120601120578stok120578self (3)




120578self =1198750

1 minus (1 minus 1198750120578120601120578trap)

(4)



1198750=int1198751015840(120592) 119864 (120592) 119889120592

int119864 (120592) 119889120592 (5)



Fluo

resc

ence

inte

nsity

(au

)

FSDED


Design 1Design 2

00 02 04 06 08 10

65

70

75

80

85

90

95

100

[Nano-SiO2] (wt)

120578 self

()




Design (1)

025

020

015

010

005

000

Effici

ency

()

Concentration ()

120578abs

120578dye

120578Conv

10

08

06

04

02

00

(a)

Design (2)

Effici

ency

()


120578dye

120578Conv

08

07

06

05

04

03

02

01

0010

08

06

04

0200

(b)



119900rdquo



119873119900

(6)



2(119899 + 1)






6 8 10 12 14 16 18 2000

02

04

06

08

10

Solar time (h)

WinterSpring

SummerAutumn

PG

(kW

m2)




4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)




120578opt = (119868sc119868ref)(119861

119866) (7)


Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )




119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863



119879


119875119863

119875119866

= 1 minus 113119870119879 (9)



6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


200 300 400 500 600 700 800 90000

02

04

06

08

10

12

14

00 02 04 06 08 1070

75

80

85

90

95

Abso

rban

ce

Wavelength (nm)

T (

)

[Nano-SiO2] (wt)

Incr

easin

g na

no-S

iO2


200 300 400 500 600 700 800 90000

04

08

12

16

00 02 04 06 08 1088

90

92

94

Abso

rban

ce

Wavelength (nm)

Incr

easin

g na

no-S

iO2

T (

)

[Nano-SiO2] (wt)



2cages of the



00 02 04 06 08 10

150

156

162

168

174

180

Refr

activ

e ind

ex

Design 1Design 2

[Nano-SiO2] (wt)






2nanohybrid




1198992 (1)





120593120578stok 120578trap 120578

120593120578stok

0 749 237 862 740 231 879005 754 239 862 773 258 88201 759 240 862 785 377 88302 765 243 862 799 418 88703 767 245 862 802 431 88704 770 246 862 803 446 88705 774 249 863 805 512 88706 779 254 863 807 581 88707 784 257 863 809 678 88608 786 259 863 812 772 88609 791 265 863 817 853 8861 803 271 8626 821 910 900

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)

Incr

easin

g na

no-S

iO2

(a)

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)In

crea

sing

nano

-SiO

2

(b)





120601


120601119903= 1 in H



120578120601= 120578120601119903(119863119904

119863119903

)(119899119904

119899119903

)

2

(1 minus 10

minusOD119903







120601and 120578stok



2





120578dye = 120578abs120578120601120578stok120578self (3)




120578self =1198750

1 minus (1 minus 1198750120578120601120578trap)

(4)



1198750=int1198751015840(120592) 119864 (120592) 119889120592

int119864 (120592) 119889120592 (5)



Fluo

resc

ence

inte

nsity

(au

)

FSDED


Design 1Design 2

00 02 04 06 08 10

65

70

75

80

85

90

95

100

[Nano-SiO2] (wt)

120578 self

()




Design (1)

025

020

015

010

005

000

Effici

ency

()

Concentration ()

120578abs

120578dye

120578Conv

10

08

06

04

02

00

(a)

Design (2)

Effici

ency

()


120578dye

120578Conv

08

07

06

05

04

03

02

01

0010

08

06

04

0200

(b)



119900rdquo



119873119900

(6)



2(119899 + 1)






6 8 10 12 14 16 18 2000

02

04

06

08

10

Solar time (h)

WinterSpring

SummerAutumn

PG

(kW

m2)




4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)




120578opt = (119868sc119868ref)(119861

119866) (7)


Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )




119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863



119879


119875119863

119875119866

= 1 minus 113119870119879 (9)



6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




120593120578stok 120578trap 120578

120593120578stok

0 749 237 862 740 231 879005 754 239 862 773 258 88201 759 240 862 785 377 88302 765 243 862 799 418 88703 767 245 862 802 431 88704 770 246 862 803 446 88705 774 249 863 805 512 88706 779 254 863 807 581 88707 784 257 863 809 678 88608 786 259 863 812 772 88609 791 265 863 817 853 8861 803 271 8626 821 910 900

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)

Incr

easin

g na

no-S

iO2

(a)

500 550 600 650 700 750

Fluo

resc

ence

(au

)

Wavelength (nm)In

crea

sing

nano

-SiO

2

(b)





120601


120601119903= 1 in H



120578120601= 120578120601119903(119863119904

119863119903

)(119899119904

119899119903

)

2

(1 minus 10

minusOD119903







120601and 120578stok



2





120578dye = 120578abs120578120601120578stok120578self (3)




120578self =1198750

1 minus (1 minus 1198750120578120601120578trap)

(4)



1198750=int1198751015840(120592) 119864 (120592) 119889120592

int119864 (120592) 119889120592 (5)



Fluo

resc

ence

inte

nsity

(au

)

FSDED


Design 1Design 2

00 02 04 06 08 10

65

70

75

80

85

90

95

100

[Nano-SiO2] (wt)

120578 self

()




Design (1)

025

020

015

010

005

000

Effici

ency

()

Concentration ()

120578abs

120578dye

120578Conv

10

08

06

04

02

00

(a)

Design (2)

Effici

ency

()


120578dye

120578Conv

08

07

06

05

04

03

02

01

0010

08

06

04

0200

(b)



119900rdquo



119873119900

(6)



2(119899 + 1)






6 8 10 12 14 16 18 2000

02

04

06

08

10

Solar time (h)

WinterSpring

SummerAutumn

PG

(kW

m2)




4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)




120578opt = (119868sc119868ref)(119861

119866) (7)


Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )




119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863



119879


119875119863

119875119866

= 1 minus 113119870119879 (9)



6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






120601and 120578stok



2





120578dye = 120578abs120578120601120578stok120578self (3)




120578self =1198750

1 minus (1 minus 1198750120578120601120578trap)

(4)



1198750=int1198751015840(120592) 119864 (120592) 119889120592

int119864 (120592) 119889120592 (5)



Fluo

resc

ence

inte

nsity

(au

)

FSDED


Design 1Design 2

00 02 04 06 08 10

65

70

75

80

85

90

95

100

[Nano-SiO2] (wt)

120578 self

()




Design (1)

025

020

015

010

005

000

Effici

ency

()

Concentration ()

120578abs

120578dye

120578Conv

10

08

06

04

02

00

(a)

Design (2)

Effici

ency

()


120578dye

120578Conv

08

07

06

05

04

03

02

01

0010

08

06

04

0200

(b)



119900rdquo



119873119900

(6)



2(119899 + 1)






6 8 10 12 14 16 18 2000

02

04

06

08

10

Solar time (h)

WinterSpring

SummerAutumn

PG

(kW

m2)




4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)




120578opt = (119868sc119868ref)(119861

119866) (7)


Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )




119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863



119879


119875119863

119875119866

= 1 minus 113119870119879 (9)



6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Design (1)

025

020

015

010

005

000

Effici

ency

()

Concentration ()

120578abs

120578dye

120578Conv

10

08

06

04

02

00

(a)

Design (2)

Effici

ency

()


120578dye

120578Conv

08

07

06

05

04

03

02

01

0010

08

06

04

0200

(b)



119900rdquo



119873119900

(6)



2(119899 + 1)






6 8 10 12 14 16 18 2000

02

04

06

08

10

Solar time (h)

WinterSpring

SummerAutumn

PG

(kW

m2)




4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)




120578opt = (119868sc119868ref)(119861

119866) (7)


Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )




119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863



119879


119875119863

119875119866

= 1 minus 113119870119879 (9)



6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


4 6 8 10 12 14 16 18 200

5

10

15

20

Solar time (h)

LSCPV cell

J sc

(mA

cm

2)




120578opt = (119868sc119868ref)(119861

119866) (7)


Autumn

Summer

Spring

WinterPV cell

TLSC

600

500

400

300

200

100

Are

a (C

cm2 )




119875119866= 119875119863+ 119875119861sin 120574 (8)

where 119875119863



119879


119875119863

119875119866

= 1 minus 113119870119879 (9)



6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


6 8 10 12 14 16 1820

25

30

35

40

45

50

Solar time (h)

WinterSpringSummer

AutumnAverage

120578 opt

()





4 Conclusions


2



Acknowledgment


References





























































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article thin-film lscs based on pmma nanohybrid...

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