x-ray lithography on perovskite nanocrystals films: from ... · x-ray lithography on perovskite...
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Supporting information for:
X-Ray Lithography on Perovskite Nanocrystals Films:
From Patterning with Anion-Exchange Reactions to
Enhanced Stability in Air and Water
Francisco Palazon, Quinten A. Akkerman, Mirko Prato,* and Liberato Manna*
Nanochemistry Department, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
* Address correspondence to
Table S1. Complete assignment of XPS peaks found on spin-coated films of CsPbBr3 NCs, as presented in Figure 1c of the paper. Binding energies are approximate and rounded to 1 eV, according with the resolution of survey spectra; higher resolution spectra were acquired on selected peaks.
Binding Energy (eV) Element Orbital Origin
738 Cs 3d3/2 Perovskite
724 Cs 3d5/2 Perovskite
645 Pb 4p5/2 Perovskite
532 O 1s Ligands
436 Pb 4d3/2 Perovskite
413 Pb 4d5/2 Perovskite
400 N 1s Ligands
352 Au 4d3/2 Substrate
335 Au 4d5/2 Substrate
285 C 1s Ligands
256 Br 3s Perovskite
189 Br 3p1/2 Perovskite
182 Br 3p3/2 Perovskite
160 Cs 4p3/2 Perovskite
143 Pb 4f5/2 Perovskite
139 Pb 4f7/2 Perovskite
87 Au 4f5/2 Substrate
84 Au 4f7/2 Substrate
78 Cs 4d3/2 Perovskite
76 Cs 4d5/2 Perovskite
69 Br 3d3/2 Perovskite
68 Br 3d5/2 Perovskite
Figure S1. PL microscopy image of a CsPbBr3 NC film after e-beam lithography and selective film
“lift-off” in toluene.
Figure S2. XPS spectra on a film of CsPbBr3 NCs as-deposited (top), after exposure to HCl vapors
(middle) and after a second exposure to HBr vapors (bottom).
Figure S3. XPS semi-quantitative profiles of cesium, bromide/cesium ratio and iodide/cesium ratio
on a film of CsPbBr3 NCs after having undergone a single X-ray irradiation and subsequent anion
exchange with iodide in toluene. Close to the center of irradiation (distance to center below 1 mm)
the film is not redispersed and remains bromide-rich. Far from the center of irradiation (distance to
center above 2.5 mm) the film is redispersed in toluene. At moderate doses (distance to center of
irradiation between 1 and 2.5 mm), NCs are still present on the substrate but mostly anion-
exchanged.
Figure S4. (Top left) Photograph of fluorescent CdSe/CdS giant shell NCs irradiated with X-rays at
two different spots on the surface (whole sample is ca. 1cm2) and exchanged into Cu2Se/Cu2S,
according to a procedure that was previously published by us.1 The NCs in the exposed areas
remain CdSe/CdS, maintaining their luminescence except for the center of the long irradiation spot,
as happens on perovskite NCs. (Bottom) SEM images of the film at different magnifications (top
row scale bar is 100 nm, bottom row scale bar is 10 nm) and different locations: (left) center of
most irradiated spot, (middle) luminescent “crown” around most irradiated spot and (right) outside
luminescent “crown”. No notable changes on the film morphology can be seen.
Figure S5: High-resolution Cs 3d, I 3d and Pb 4f XPS spectra of a CsPbI3 nanocrystal film after
different irradiation times (t=0 –black-, 2.5 h –red- and 5 h –blue-) . No noticeable changes in the
chemical composition of the nanocrystals can be seen that could explain the observed loss of
photoluminescence.
Figure S6 : High-resolution SEM images of a CsPbI3 nanocrystal film before (a-b) and after (c-d)
X-ray irradiation. No significant changes in the film and single crystal morphologies can be
appreciated. Scale bars are 100nm.
Figure S7. PL emission spectra of a CsPbI3 NC solution and of a CsPbI3 NC film having
undergone ageing steps in air, water and biological buffer. A slight red-shift is observed on the film
(20 nm; 0.05 eV) which is likely undue to the ageing since similar results were already observed
comparing PL measurements of similar particles in solution and on film.2
Additional References
1. Miszta, K.; Greullet, F.; Marras, S.; Prato, M.; Toma, A.; Arciniegas, M.; Manna, L.;
Krahne, R., Nanocrystal Film Patterning by Inhibiting Cation Exchange via Electron-Beam or X-
ray Lithography. Nano Lett. 2014, 14 (4), 2116-2122.
2. Akkerman, Q. A.; D'Innocenzo, V.; Accornero, S.; Scarpellini, A.; Petrozza, A.; Prato, M.;
Manna, L., Tuning the Optical Properties of Cesium Lead Halide Perovskite Nanocrystals by Anion
Exchange Reactions. J. Am. Chem. Soc. 2015, 137 (32), 10276-81.