CsPbBr₃ Solar Cells: Controlled Film Growth through Layer-by-Layer Quantum Dot Deposition

Abstract

All inorganic cesium lead bromide (CsPbBr3) perovskite is a more stable alternative to methylammonium lead bromide (MAPbBr3) for designing high open-circuit voltage solar cells and display devices. Poor solubility of CsBr in organic solvents makes typical solution deposition methods difficult to adapt for constructing CsPbBr3 devices. Our layer-by-layer methodology, which makes use of CsPbBr3 quantum dot (QD) deposition followed by annealing, provides a convenient way to cast stable films of desired thickness. The transformation from QDs into bulk during thermal annealing arises from the resumption of nanoparticle growth and not from sintering as generally assumed. Additionally, a large loss of organic material during the annealing process is mainly from 1-octadecene left during the QD synthesis. Utilizing this deposition approach for perovskite photovoltaics is examined using typical planar architecture devices. Devices optimized to both QD spin-casting concentration and overall CsPbBr3 thickness produce champion devices that reach power conversion efficiencies of 5.5% with a V oc value of 1.4 V. The layered QD deposition demonstrates a controlled perovskite film architecture for developing efficient, high open-circuit photovoltaic devices.

Unveiling the Photo‐ and Thermal‐Stability of Cesium Lead Halide Perovskite Nanocrystals

“…[51] We observe this as well (by comparing the SNR of normalized spectra), along with slight shifts in the luminescence maximum. [75][76] These results are similar to recent reports showing TGA measurements of CsPbI 3 , [74] CsPbBr 3 , [77] and Mn 2 + -doped CsPbCl 3 . For CsPbBr 3 and CsPbI 3 , slight blue shifts are observed with heating, however, CsPbBr 3 does not shift back upon cooling, indicating an irreversible process occurred.…”

Anorganische CsPbX3‐Perowskit‐Solarzellen: Fortschritte und Perspektiven

“…[132] Zellen mit optimierter QD-Konzentration und Dicke der CsPbBr 3 -Schicht zeigten 5.5 % PCE und V OC > 1.4 Vm it sehr geringer Hysterese.K ürzlich stellten Zhang et al Nanokristall-Filme (10-20 nm) aus CsPbBr 3 her und prozessierten diese mit NH 4 SCN in Ethylacetatlçsung.D ie erfolgende Auflçsung/Umkristallisation führte zu einem CsPbBr 3 -CsPb 2 Br 5 -Kompositfilm mit grçßerer Kristallgrçße (Abbildung 7c). [132] Zellen mit optimierter QD-Konzentration und Dicke der CsPbBr 3 -Schicht zeigten 5.5 % PCE und V OC > 1.4 Vm it sehr geringer Hysterese.K ürzlich stellten Zhang et al Nanokristall-Filme (10-20 nm) aus CsPbBr 3 her und prozessierten diese mit NH 4 SCN in Ethylacetatlçsung.D ie erfolgende Auflçsung/Umkristallisation führte zu einem CsPbBr 3 -CsPb 2 Br 5 -Kompositfilm mit grçßerer Kristallgrçße (Abbildung 7c).…”

“…In einer weiteren Studien wurden flexible Solarzellen auf Basis solcher Filme mit sPCE von 10.8 %h ergestellt. [132,133] Im Gegensatz zu CsPbI 3 ist CsPbBr 3 in der orthorhombischen Struktur nahe Raumtemperatur stabil. 5%von Pb) mit einer moderaten Verbesserung der Stabilität.…”

Caesium for Perovskite Solar Cells: An Overview

“…Hoffman et al. developed a layer‐by‐layer deposition procedure for bulk CsPbBr 3 from fully suspended CsPbBr 3 quantum dots that provided controllable thickness and a cubic perovskite crystal structure . This deposition method allowed achieving films with controllable thickness and growth rate in a very simple way.…”

“…[168,169] Hoffman et al developed al ayer-by-layerd eposition procedure for bulk CsPbBr 3 from fully suspended CsPbBr 3 quantum dots that provided controllable thickness and ac ubic perovskite crystal structure. [170] This deposition methoda llowed achieving films with controllable thickness and growth rate in av ery simple way.Aseries of parameters were considered to increase the efficiency of CsPbBr 3 PSCs, including the spin-casting solution rate, the annealing temperature and the thickness of the final film. Spin-casting solution at lower concentration required ah ighern umber of deposition cycles.…”