Efficient Inorganic Cesium Lead Mixed‐Halide Perovskite Solar Cells Prepared by Flash‐Evaporation Printing

Abstract

Cesium‐based inorganic perovskites have attracted enormous interest for efficient and stable photovoltaics, while still a few studies apply evaporation methods with high reproducibility to prepare them. Herein, high‐quality CsPbI2Br films are deposited by flash‐evaporation printing (FEP), a single source evaporation method using laser as the heating source and carbon nanotube sheets as the evaporator. Uniform films with balanced stoichiometry and high crystallinity can be obtained by controlling the precursor ratio and post‐annealing conditions. Planar solar cells using these inorganic perovskite films exhibit champion power conversion efficiencies of 12.2% in small areas (0.06 cm2) and 9.4% in large areas (1 cm2) with insignificant hysteresis, indicating that the FEP method is a promising way in preparing high‐quality inorganic perovskite films for efficient large‐area devices.

All-Inorganic CsPbBr3 Perovskite Films Prepared by Single Source Thermal Ablation

“…High temperature annealing is then an issue whenever smooth and pinhole-free films are needed. Work is in progress to investigate if short annealing processes similar to those discussed by Tai et al (2019) may be used profitably to increase grain size while maintaining films smooth and compact.…”

“…A different situation may be expected when MA is replaced by cesium because the vapor pressures of Cs halides are a few orders of magnitudes lower than that of methylammonium halides. To the best of our knowledge, flash evaporation of Csbased halide perovskites was only recently reported (Tai et al, 2019), but using a technique named "flash-evaporation printing" (FEP). FEP is less simple than SSTA since it exploits a laser beam as the heating source and carbon nanotube sheets as the evaporator onto which perovskite solution is spin coated.…”

Vapor phase deposition of perovskite photovoltaics: short track to commercialization?

“…Recent investigations on single source, laser, or sputtering approaches for the deposition of perovskites might be of particular interest. 44,45,83,100,101 Sequential deposition strategies that decouple the deposition of inorganic and organic compounds might also be of interest as they circumvent some issues of the complex thin-film formation in co-evaporation by decoupling the monitoring of the composition and the film formation. For a practical application, further progress is also required in the development of deposition strategies that can be operated continuously.…”

Continuous flash sublimation of inorganic halide perovskites: overcoming rate and continuity limitations of vapor deposition

“…23 In most of these ash sublimation approaches, a metal foil is coated with a thin lm of the target material using solutionbased processes and the resulting foil used as the source material for the vapor deposition. [24][25][26][27] This two-step process of solution casting followed by vapor deposition is obviously not practical for high-throughput commercial processing, has not demonstrated high performing devices, does not leverage the environmental advantages of vapor processing by removing solvents from the process, and increases the overall processing complexity; as such, these techniques have not been included in Fig. 1 but are tabulated and marked in Tables S1 and S2 in the ESI.…”