novel materials in renewable energy

8/18/2019 Novel materials in renewable energy

1/19

MSC. INNOVATIVE TECHNOLOGY ENGINEERING

NOVEL MATERIALS

MATERIALS SCIENCE & ENGINEERING

IN

RENEWABLE ENERGY AREA

By

Bruno Pereira Franco

20070520


2/19

BRUNO P. FRANCO MSC. I NNOVATIVE TECHNOLOGY E NGINEERING 15/04/2016

- i -

DECLARATION

The work submitted in this report is the results of the candidate’s own investigations and

has not been submitted for any other award. Where use has been made of the work of other

people it has been fully acknowledged and referenced.

Student Name

______________


3/19


- ii -

TABLE OF CONTENTS

TABLE OF CONTENTS .................................................................................................... ii

Chapter 1 Introduction ........................................................................................................ 1

Chapter 2 Solar Cells: Generations and Materials .............................................................. 2 2.1 Crystalline Silicon Solar Cells ................................................................................. 2

2.2 Thin-Film Solar Cells ............................................................................................... 4

Chapter 3 Self-Healing Materials for Wind Turbine .......................................................... 7 3.1 Incorporation of Self-healing Materials ................................................................... 8

Chapter 4 Thermal Energy Storage with Phase Change Materials ................................... 11

4.1.1 Incorporation of PCM .................................................................................... 12 4.1.2 PCM Thermal Enhancement .......................................................................... 13

Chapter 5 Conclusions and Recommendations ................................................................. 14

Chapter 6 Bibliography ..................................................................................................... 15

LIST OF FIGURES

Figure 1 Polystyrene Nanospheres with Ag coating in Silicon Wafer: SEM image (left) and

diagram (right) (Xu, et al., 2016) ........................................................................................ 3

Figure 2 Nanosphere Lithography Process [From (Colson, et al., 2013)] .......................... 3

Figure 3 CSS system diagram [From (Pinheiro, et al., 2006)] ........................................... 5 Figure 4 Chemical Bath Deposition [From (Singh, 2014)] ................................................ 6

Figure 5 CdTe solar cell with all layers [From (http://www.nrel.gov/pv/thinfilm.html)] .. 6

Figure 6 Self-healing process [From (Hager, et al., 2010)] ................................................ 8 Figure 7 Self-Healing Microcapsules (a) and Hollow-Fibre (b) ......................................... 8

Figure 8 Microcapsules with average diameter [From (Li, et al., 2012)] ............ 9

Figure 9 Diameter Hollow Glass Fibres [From (Trask, et al., 2007)]................... 10


4/19


- 1 -

Chapter 1 Introduction

Materials science is considered one of the most important fields of study nowadays.

It studies the relationship between structure and properties of materials, and works in

expanding knowledge of the materials by setting their potential use and limitations. It aims

to develop materials that have the better performance, durability, properties, and cost for

different applications. And today, with the capability to examine and modify materials at

molecular level the interest for this area became greater, it is allowing the development of

advanced materials (with enhanced properties and smart reaction to external stimulus).

Material science can be applied to guarantee improvements in all types of fields, such as

transportation (engine efficiency), clothes (thermal control), construction (smart

structures), medicine and medical devices (manmade materials that mimic biological

materials for the use in implants) and many others. The field that will be analysed in this

report is the renewable energy.

At a time when the consumption of electricity has increased, and that a progressive

general awareness of the environmental impacts of fossil fuel use arises, it becomes

imperative a bet on clean energy sources, sustainably produced. Thus, investment in

renewable energy has been gaining momentum, driven by European directives stipulate

that an incorporation of renewable energy from the electrical system. Renewable Energy

is a wide area including many different technologies such as wind turbines, solar cells,

hydroelectric, energy storage systems, biofuels, marine energy technologies, etc.

Many advances in renewable energy technologies were possible only because of

the study of material science. Researches have been conducted to enhance the performance

of renewable energy technologies with focus on material science. The focus of this report

is to present some of these researches as case studies. Chapter 2 present advances that

materials science underpinned in the first two generations of solar cell. Chapter 3 describes

the use of self-healing materials in wind turbine blades. Chapter 4 shows the importance

of phase change materials for thermal energy storage. Chapter 5 brings the report

conclusion. It is important to notice that the description of how the renewable energy

technologies work is not in scope of this report.


5/19


- 2 -

Chapter 2 Solar Cells: Generations and Materials

Solar cells are responsible to take incoming light energy and convert it to electrical

energy (the photoelectric effect). Nowadays, there are at least 3 generations of solar cells,

the crystalline silicon solar cells, the thin-film solar cells, and many technologies form the

third generation of solar cells. In all these 3 generations there is a continue research, which

is mainly focused in material science, to improve efficiency and reduce production costs.

This chapter is focused in the use of materials science in the first two generations, it

includes the use nanostructures to enhance the light absorption of crystalline silicon cells,

and the process to create cadmium telluride thin-film solar cells.

2.1 Crystalline Silicon Solar Cells

The first generation of solar cells, the crystalline silicon, or c-Si, uses silicon as its

main material. Silicon can be consider the most relevant material for solar cells due to its

long history with the technology and it has the best semiconductor properties to be used in

this application. The silicon is not found in its isolated and native state, it appears in some

minerals in the form of silicon dioxide (SiO2), also known as silica (as in amethyst, the

agate, quartz, sand, etc.) and other minerals in the form of compounds containing silicon,

oxygen and metals known as silicate (in clay, feldspar, granite, on mica, etc.). Silicon is

the main component of glass, cement, ceramics, and most of the semiconductor component,

as well as silicones, plastics substances that are often confused with silicon.

There are two types of crystalline structures, the monocrystalline, which represents

the most efficient solar cells, however it has the most expensive and energy intensive

production process; and the polycrystalline, which presents decrease in the efficiency,

however the production process is less costly. There are many process, or methods, to

create the silicon crystals, such as, the Czochralski (CZ) and Float Zone Silicon (FZ) for

the creation of monocrystalline silicon (details can be found in Meroli, 2012); and the

directional solidification (DS) and electromagnetic casting (EMC) for the creation of

polycrystalline silicon (detail can be found in www.siliconsultant.com/simulticrs.htm).

Current c-Si cell have low absorption of the near infrared light (exceeding 800nm

wavelength). A possible upgrade in c-Si solar cells is the use of nanosphere-embedded

metallic grating structure to improve light absorption. Nanosphere lithography was used to

http://www.siliconsultant.com/simulticrs.htmhttp://www.siliconsultant.com/simulticrs.htmhttp://www.siliconsultant.com/simulticrs.htmhttp://www.siliconsultant.com/simulticrs.htm


6/19


- 3 -

create hexagonal distributed polystyrene nanospheres embedded in silver (Ag coating) in

the rear surface of the silicon wafer (Figure 1). The Ag coating forms the grating structure

and acts as electrode (to collect electrical energy from the solar cell). This structure in the

rear part of the c-Si cell traps the light with higher wavelengths, which can enhances the

performance of the cell. The great advantage of this new method is the fact that it can be

integrated as final step of fabrication process, not adding any complication to it (Xu, et al.,

2016).

Figure 1 Polystyrene Nanospheres with Ag coating in Silicon Wafer: SEM image (left) and diagram (right) (Xu, et al ., 2016)

Figure 2 Nanosphere Lithography Process [From (Colson, et al., 2013)]


7/19


- 4 -

Two interesting aspects of this method described is the use of nanosphere

lithography to create the structure. Nanosphere lithography is a method nanomaterials,

nanostructures in different sizes. The method consists in two main steps, the mask

preparation and nanostructure creation; the entire process can be seen in Figure 2. In the

final step of the mask formation the 2D HPC lattice stands for the formation of a monolayer

or bilayer hexagonal-closed pack (Colson, et al., 2013).

2.2 Thin-Film Solar Cells

The second generation, the thin film solar cells also use silicon but in its amorphous

(a-Si) form, however it can also be made with other materials, such as Gallium Arsenide

(GaAs) and Cadmium Telluride (CdTe) (www.energyinformative.org). These solar cells

use much less material compared with the first generation (10nm of film thickness

compared with 200nm wafer thickness). With less material usage and less expensive

production process these cells are an alternative to crystalline silicon cells, however the

efficiency is lower (8% in commercialized products) since they cannot absorb the same

quantity of light as c-Si cells (www.energy.gov).

One important characteristic of these cells is their manufacturing process, which

can be made in mass production (1 module per minute) and much less energy intensive

compared with c-Si. There are different methods and technologies depending on the typeof the thin-film solar cell. CdTe has been seen as the best thin-film solar cell technology

(7% of the world’s market) and the methods to produce the thin-film include close-spaced

sublimation (CSS), vapor-transport deposition, physical-vapor deposition, sputter

deposition, electrodeposition, metal-organic chemical-vapor deposition (CVD), spray

deposition, and screen-print deposition (www.energy.gov).

CSS is considered a good deposition method to growth CdTe in a substrate because

it works with not so high temperatures and can be implemented for in-line production. In

this technique, the source and the substrate are separated by a distance of millimeters by

quartz spacers. Graphite blocks serve as support for source and for substrate, and serve to

transport heat that is provided by visible or infrared lights facing the blocks.

Thermocouples serve to monitor the temperature of the graphite blocks, which is important

since the temperature difference between source and substrate determines the material

http://www.energyinformative.org/http://www.energyinformative.org/http://www.energyinformative.org/http://www.energy.gov/http://www.energy.gov/http://www.energy.gov/http://www.energy.gov/http://www.energy.gov/http://www.energy.gov/http://www.energy.gov/http://www.energy.gov/http://www.energyinformative.org/


8/19


- 5 -

transfer between both (Figure 3). The process itself start with the heating of the source

material until it generate a required amount of vapor. In the surface of the substrate, which

is in a temperature lower than the source, the vapor condense. It allow the use of different

substrates, such as polymers, metals and glasses, and the use of different dopants for the

source (to enhance the efficiency of the cell) (Seth, et al., 1999).

Figure 3 CSS system diagram [From (Pinheiro, et al., 2006)]

The process of fabrication the CdTe cell include seven steps. The first is preparation

of the substrate, which stands for cleaning it to avoid impurities in the cell (different

cleaning methods can be found in Snyder, 2000).

Secondly is necessary to create the frontal electrical contact of the cell, by adding

a transparent conducting oxide (TCO) (electrical conductive material with low absorptionof light characteristic). Tin Dioxide (SnO2) and Indium Tin Oxides (ITO) are both good

options for TCO in CdTe cells, the first one can be applied to the substrate using CVD

techniques and the second one by sputtering deposition process (Singh, 2014).

The next layer of the cell is the deposition of CdS layer that can be done the

chemical bath deposition (CBD), which gives the cell a better performance; however, it is

not proper for mass production processes, so CSS can also be used. Figure 4 shows the

CBS process for a substrate with ITO TCO coating, where the substrate is dipped in

deionized water at temperature around 87℃. Different chemical compounds are added

separately in the water, which result in the deposition of CdS (Singh, 2014). The next step

is the addition of the CdTe layer that can be done with the CSS method. Then it is necessary

to treat the CdTe layer for the addition of the back contact and finally the addition of the

back contact (detail for the entire process can be found in Britt & Ferekides, 1993).


9/19


- 6 -

Figure 4 Chemical Bath Deposition [From (Singh, 2014)]

Figure 5 CdTe solar cell with all layers [From (http://www.nrel.gov/pv/thinfilm.html)]

http://www.nrel.gov/pv/thinfilm.htmlhttp://www.nrel.gov/pv/thinfilm.htmlhttp://www.nrel.gov/pv/thinfilm.htmlhttp://www.nrel.gov/pv/thinfilm.html


10/19


- 7 -

Chapter 3 Self-Healing Materials for Wind Turbine

One may think that wind energy would not be dependent on the materials science

to achieve a better performance (efficiency), since it is based on a mechanical process

different of the chemical process of the other renewable energy from the last chapter,

however, this is not truth. Just modifying the design of the blades, or improvements in the

electro-mechanical conversion are not the only ways to improve the performance of this

device. Increase in the wind turbine blade length, which is normally made of polymers

(carbon-fibre/epoxy, carbon fibre/polyester or glass reinforced thermoset), can guarantee

that the turbine will extract more power from the wind, thus more efficient, however

problems with the blade weight and the risk of fracture not allow this advance. The

development of light and resistant materials may not be enough to achieve thisimprovement. Fatigue failure can happen due to micro and nanocracks that are formed in

the blade due to external cyclical loadings, which decreases the turbine life-cyle. One

solution to this problem is the use introduction of self-healings materials in the blade

manufacturing process (Patlolla & Asmatulu, 2012).

Wind turbine structural and blade failures represent more than 23% of the cases,

and it is important to notice that the accidents were not just in storms or strong wind

conditions (Lu, 2014). Damage in the wind blades is not only a problem for the efficiency

and turbine lifetime, but it can be a critical safety problem for workers in the wind farm, or

depending on the situation for people living in the proximity of the device. Even with the

use of fibre-reinforced material is impossible to avoid damage caused by micro-cracks that

can propagate causing a major failure. Conventional repair methods are not able to fix

micro/nano-cracks, thus another approach is required (Amano, 2014).

Self-healing is a common property observed in biological materials (bones, animal

or vegetal tissues, etc) that were damaged by external mechanical load. The objective to

achieve self-healing property in man-made materials can allow the production of coating

with this property that would be used in any applications that have difficult access and are

made to have a long life-time, such as wind turbines, off-shore devices and others. The

basic process of self-healing can be seen in Figure 6, where after the material is damaged

with a micro or nano crack, then a “mobile phase” is generated, which is activated by an


11/19


- 8 -

external stimulus (named non-autonomic self-healing materials) or as an automatic

response to the crack (named autonomic self-healing materials). Mass is transported to the

damaged region and the crack repair happens with physical and/or chemical reactions.

After the repair is completed the mobile material is immobilized, which can result in a

repaired main material with its full properties (best-case scenario). (Hager, et al., 2010)

Figure 6 Self-healing process [From (Hager, et al., 2010)]

A common self-healing agent for polymers is Dicyclopentadiene (DCPD), which

used as a monomer capable of fast polymerization. Grubbs’s catalyst is required in the

polymerization process (to increase the velocity of the chemical reaction). DCPD or any

other healing agent must be inside a container, which will release the agent when a damage

occurs. Chemical reactions including the breakage of DCPD bonds and the formation of

new bonds with the main material (bulk material) will guarantee the repair of the crack.

More details about the reactions of DCPD can be found in (Li, et al., 2012).

3.1 Incorporation of Self-healing Materials

Approaches to apply self-healing materials in wind turbine include: the use of self-

healing microcapsules or hollow-fibre (Figure 7) (Amano, 2014).

Figure 7 Self-Healing Microcapsules (a) and Hollow-Fibre (b)


12/19


- 9 -

The microcapsules contain the healing material, which can be a monomer that is

released when the material suffer mechanical damage (breaking the wall of the capsule).

With the support of a catalyst agent the monomer would start the polymerization process

in the crack, repair the damage. One important engineering process related to materials

science can be highlight in the use of self-healing microcapsules, the microencapsulation

(Hager, et al., 2010).

Figure 8 Microcapsules with average diameter [From (Li, et al., 2012)]

In the technical report of Microtek laboratories Inc., microencapsulation is “ defined

as the process of surrounding or enveloping one substance within another substance on

a very small scale, yielding capsules ranging from less than one micron to several

hundred microns in size”. There are many techniques used in microencapsulation such

as chemical techniques: Complex Coacervation, Interfacial Polymerization, and In situ

polymerization; and physical of mechanical techniques: Spray Drying, Fluid Bed

Coating, and Spinning Disk method. Details for each of these techniques can be found

in (Microtek Laboratories Inc., 2015).

The self-healing microcapsule works well, however it has the main drawback is the

fact that it could lead to an incomplete repair due to lack of material in the capsule

(Hager, et al., 2010).

One alternative to the use of self-healing microcapsule is hollow glass fibres. A

matrix of these hollow fibres, which can be seen as a tube system, is integrated in the

material. When the material is damaged, a fracture will release the self-healing materials

from the tubes. These are preferred due to the advantage capability to store self-healing


13/19


- 10 -

material, plus easy integration in the main material system and plus the fact that it can

also act as a reinforcement (Trask, et al., 2007).

Figure 9 Diameter Hollow Glass Fibres [From (Trask, et al., 2007)]

One problem with both methods above is the fact that sometimes the external load,

which causes the micro or nano crack in the bulk material, not necessarily will cause the

required stress to promote the rupture of the microcapsule or hollow glass fibre wall. In

one attempt to solve this issue a recent method was developed to create a biomimetic

vascular system in wind turbines blades to allow the “circulation” of self-healing agent is

presented in Strong & Guo, 2015. The network is created by using 100 metal wires,

which are coated with release film. By using, the vacuum assisted resin transfer method

(VARTM, detail of the method can be found in https://www.rtmcomposites.com/process/vacuum-

assisted-resin-transfer-molding-vartm) the wires are removed from the bulk material interior, which

creates the complex matrix where the self-healing agent can be inserted (Strong & Guo,

2015).

https://www.rtmcomposites.com/process/vacuum-assisted-resin-transfer-molding-vartmhttps://www.rtmcomposites.com/process/vacuum-assisted-resin-transfer-molding-vartmhttps://www.rtmcomposites.com/process/vacuum-assisted-resin-transfer-molding-vartmhttps://www.rtmcomposites.com/process/vacuum-assisted-resin-transfer-molding-vartmhttps://www.rtmcomposites.com/process/vacuum-assisted-resin-transfer-molding-vartm


14/19


- 11 -

Chapter 4 Thermal Energy Storage with Phase Change

Materials

Energy storage systems play an important role to achieve a better use of the energy

from renewable sources. The best example to show the importance of these systems is in

solar energy, where the energy source (the sun) will be only available during the day, thus

it is required to store energy to use in the night time (assuming a closed system where only

solar energy is available). In off peak hours (during the night), wind energy continue to be

generated, and it can wasted if not properly stored. There are a number of technologies that

can be used in energy storage system, including thermal, compressed air, pumped hydro-

power, flywheels, flow batteries and solid state batteries (detailed information about the

working process of each one of these technologies can be found in

www.energystorage.org). This chapter focus on thermal energy storage with the use of

phase change materials.

Thermal Energy Storage is a method that can provide heating or cooling of different

ambient (buildings, houses, cluster cooling, etc.) with the utilization of excess electrical

energy to heat or cool a storage system, or by capturing heat/cold from external sources

(sun, summer heat, winter cold, geothermal) and storing it. The energy stored can be

utilized in its thermal form and it would not return to electrical form (although there are

recent studies that try to use thermoelectric generator to transform the thermal energy

stored in electrical energy). The thermal energy can be stored as sensible heat, latent heat

or thermochemical, however in this work, only the latent heat storage will be analyzed

(www.irena.org).

Latent heat is the heat absorbed or released as result of a phase change

(www.physics.info/heat-latent/). In Latent Heat Storage, the thermal energy is stored in

latent mode by changing the state, or phase (solid-liquid-gas) of the storage medium, which

is normally a phase change material. Phase change material (PCM) absorbs and release

thermal energy in while changing their state, with the objective to maintain a regulated

temperature. The most used PCM materials for energy storage applications are the solid-

solid type and the solid-liquid type, the use of any material that includes a gas phase is also

possible, but required a storage system more complex and expensive. Commercialized

http://www.energystorage.org/http://www.energystorage.org/http://www.irena.org/http://www.irena.org/http://www.irena.org/http://www.physics.info/heat-latent/http://www.physics.info/heat-latent/http://www.physics.info/heat-latent/http://www.physics.info/heat-latent/http://www.irena.org/http://www.energystorage.org/


15/19


- 12 -

PCM are classified in organic (paraffins, fatty acids, polyglycols), inorganic (salt hydrates)

and eutectics (salt-water solutions) (http://www.microteklabs.com/what-is-a-pcm.html).

The most useful application of PCM’s is in the energy storage for buildings.

Buildings consume almost 45% of the fossil energy, which contributes a lot for emissions

of greenhouse gases. Great part of this energy consumption is in ambient thermal control

(heating, cooling, and ventilation). One way to reduce this energy consumption is to use

PCM as latent heat storage. In this application, it is required PCM’s that a have a phase

change temperature close the human thermal comfort (21℃ − 25.5℃), the most viable

option is the use of material with phase change temperature around18℃ − 30℃ (Zhou, et

al., 2012).

4.1.1 Incorporation of PCM

A great challenge in buildings application is how to integrate the PCM material

with the building material. Traditional methods include direct incorporation, immersion

and macroencapsulation, the first two methods present problems with reactions that may

occur with the direct contact of the PCM with the building material, the third method solve

the contact problem however has other disadvantages such as: low thermal conductivity

and difficult integration with building material (more detail for these 3 methods can be

found in Hawes, et al., 1993). Recent methods include microencapsulation and shape-

stabilized PCMs.The microencapsulation is the same method used for self-healing materials in

Chapter 3; however, the microcapsules for PCM cannot fracture different from the

microcapsules for self-healing, in other words, the capsule must guarantee no leakage. The

great advantage of this method is to offer a good heat transfer coefficient that increases the

performance of the thermal storage. All the techniques listed in Chapter 3 can be used to

produce microencapsulated PCM (Zhao & Zhang, 2011).

Other way to incorporate PCM in buildings material is the use of shape-stabilized

PCM, which even if the melt point of the material is passed the shape is retained. In this

different type of materials, a supporting material (liquid polymer, normally high density

polyethylene, HDPE) and a dispersed PCM (normally paraffin) are used to form a stable

composite material. Both materials are melt and blended (higher the PCM concentration

better the thermal performance, the maximum achieved was of 85% PCM concentration),

http://www.microteklabs.com/what-is-a-pcm.htmlhttp://www.microteklabs.com/what-is-a-pcm.htmlhttp://www.microteklabs.com/what-is-a-pcm.htmlhttp://www.microteklabs.com/what-is-a-pcm.html


16/19


- 13 -

creating a polymeric PCM hybrid. The supporting material contain the PCM material using

capillary forces in their cellular structure. The good thermal properties and the fact that it

does not need a container for the material make shape-stabilized PCM interesting for the

use in many applications. Any shape can be achieved for these types of materials. Important

to notice that any material that can provide capillary forces to retain the PCM can be used

as supporting material, recent new shape-stabilized PCM uses graphene oxide (GO) to

improve thermal properties (more details can be found in Mehrali, et al., 2013) (Fleischer,

2015).

4.1.2 PCM Thermal Enhancement

The low thermal conductivity of PCMs is a disadvantage for energy storage

application, since it is required more time to absorb and release thermal energy. A relevant

technique to solve this problem and enhance PCM thermal conductivity is the use of

nanomaterials (nanoparticles, nanofibers, nanotubes and nanosheets) to create nano-

enhanced PCMs (NEPCM). It is possible to use metallic or non-metallic nanomaterials for

this application, including copper, aluminum, carbon nanotubes, graphite nanofibers and

others. As in the shape-stabilized PCM, the concentration of any non-PCM material must

be as minimum as possible to maintain the main properties. The most used method to create

NEPCM is first to produce the nanomaterial and secondly to disperse this material in PCM

base fluid. Surfactants are used to guarantee stability of the new mixture. The main

objective is to increase the velocity of the phase change process, however any approach

must not over increase the weight of the overall material or the cost of production (Ma, et

al., 2016).


17/19


- 14 -

Chapter 5 Conclusions and Recommendations

This report has stated the importance of materials science in renewable energy area

by presenting three different cases. It is possible to notice that the subject involves different

types of materials, nanostructures and process of manufacturing, thus a more extensive

work would be necessary for a full review of the most recent advances in the area.

Nevertheless, this mini-review was able to show some important advances.

In chapter 2, it was possible to see the use of material science studies to enhance

the perform of solar cells. In the first case, for the crystalline silicon solar cells a new

method to increase light absorption (trapping) of the cell is proposed by using a nanostructe

of polystyrene and silver in the rear part of the cell. In the second case, the production

process of cadmium telluride solar cells was reviewed, with focus in the close-spacesublimation technique to deposit thin layer of CdTe in a substrate.

In chapter 3, improvements in wind turbine structural health were shown with the

use of self-healing materials. The material mechanism was briefly explained and two

techniques to insert the material in the turbine blade were stated.

In chapter 4, the use of PCM for thermal energy harvesting was highlighted. It was

reported that the buildings sector is the best application for this material and techniques to

use the material were shown. In the end, the possibility to enhance the thermal conductivity

of the material using nanomaterial was explained.


18/19


- 15 -

Chapter 6 Bibliography

Amano, R., 2014. Structural Consideration For Wind Turbine Blades. WIT Transactions

on State-of-the-art in Science and Engineering, Volume 81, pp. 161-179.

Britt, J. & Ferekides, C., 1993. Thin‐film CdS/CdTe solar cell with 15.8% efficiency.

Applied Physics Letters, Volume 62(22), pp. 2851-2852.

Colson, P., Henrist, C. & Cloots, R., 2013. Nanosphere lithography: a powerful method for

the controlled manufacturing of nanomaterials.. Journal of Nanomaterials, p. 21.

Fleischer, A., 2015. Thermal Energy Storage Using Phase Change Materials:

Fundamentals and Applications. s.l.:Springer.

Hager, M. et al., 2010. Self ‐Healing Materials. Advanced Materials, 22(47), pp.5424-

5430., Volume 22(47), pp. 5424-5430..

Hawes, D., Feldman, D. & Banu, D., 1993. Latent heat storage in building materials.

Energy and buildings, Volume 20(1), pp. 77-86.

Li, Z., Morrison, C. & St. Laurent, E., 2012. Damage Detection in a Microencapsulated

Dicyclopentadiene and Grubbs’ Catalyst Self -Healing System.

https://www.wpi.edu/Pubs/E-project/Available/E-project-030415-

201853/unrestricted/MQP_Report_-_Li,_Morrison,_St._Laurent.pdf.

Lu, K., 2014. Materials in energy conversion, harvesting, and storage. s.l.:John Wiley &

Sons.

Ma, Z., Lin, W. & Sohel, M., 2016. Nano-enhanced phase change materials for improved

building performance. Renewable and Sustainable Energy Reviews, Volume 58, pp. 1256-

1268.

Mehrali, M. et al., 2013. Shape-stabilized phase change materials with high thermal

conductivity based on paraffin/graphene oxide composite. Energy Conversion and

Management, Volume 67, pp. 275-282.

Meroli, S., 2012. Meroli. [Online]

Available at:

http://meroli.web.cern.ch/meroli/Lecture_silicon_floatzone_czochralski.html

[Accessed 2016].


19/19


- 16 -

Microtek Laboratories Inc., 2015. Technical Overview: Microencapsulation, Dayton:

Microtek Laboratories Inc..

Patlolla, V. & Asmatulu, R., 2012. New progress in self-healing technology of composite

wind turbine blades. 9th Annual Capitol Graduate Research Summit.

Pinheiro, W., Falcão, V., Cruz, L. & Ferreira, C., 2006. Comparative study of CdTe sources

used for deposition of CdTe thin films by close spaced sublimation technique. Materials

Research, , Volume 9(1), pp. 47-49.

Seth, A. et al., 1999. Growth and characterization of CdTe by close spaced sublimation on

metal substrates. Solar energy materials and solar cells, Volume 59(1), pp. 35-49.

Singh, V. P., 2014. The University Of Texas CdTe-Based Solar Cell Project. [Online]

Available at: http://www.ece.utep.edu/research/cdte/Fabrication/

[Accessed 13 04 2016].

Snyder, D. D., 2000. Preparation for Deposition. In: Modern Electroplating 4th Edition.

s.l.:John Wiley & Sons, Inc, pp. 739-748.

Strong, S. & Guo, J., 2015. Development of Novel Self-Healing for use in Wind Turbine

Blades. http://dc.uwm.edu/uwsurca/2015/Poster2/12/.

Trask, R., Williams, G. & Bond, I., 2007. Bioinspired self-healing of advanced composite

structures using hollow glass fibres. Journal of the royal society Interface, Volume 4(13),

pp. 363-371.

Wang, X. et al., 2015. Nano-encapsulated PCM via Pickering Emulsification.. Nature -

Scientific reports, Volume 5.

Xu, Q., Johnson, C., Disney, C. & Pillai, S., 2016. Enhanced Broadband Light Trapping in

c-Si Solar Cells Using Nanosphere-Embedded Metallic Grating Structure. IEEE Journal

of Photovoltaics, Volume 6(1), pp. 61-67.

Zhao, C. & Zhang, G., 2011. Review on microencapsulated phase change materials

(MEPCMs): fabrication, characterization and applications. Renewable and Sustainable

Energy Reviews, Volume 15(8), pp. 3813-3832.

Zhou, D., Zhao, C. & Tian, Y., 2012. Review on thermal energy storage with phase change

materials (PCMs) in building applications.. Applied energy, Volume 92, pp. 593-605.

novel materials in renewable energy

Documents