High-Valent Iodoplumbate-Rich Perovskite Precursor Solution via Solar Illumination for Reproducible Power Conversion Efficiency

Abstract

The power conversion efficiency (PCE) of solution-processed organic–inorganic hybrid perovskite solar cells has been drastically improved. Despite this considerable progress, systematic research on precursor solution chemistry and its effects on photovoltaic parameters has been limited thus far. Herein, we report on the tracking of changes in chemical species in a precursor solution under solar illumination and investigate the correlation between the equilibrium change and the corresponding perovskite film formation. The illuminated perovskite precursors display a higher density of high-valent iodoplumbate, where the resulting perovskite film exhibits reduced defect density with uniform film formation. Conclusively, the perovskite solar cells prepared by the photoaged precursor solution demonstrate not only improved average PCE but also enhanced reproducibility with a narrow PCE distribution. This discovery shows robust control of perovskite precursor solutions from a simple treatment and suggests that the resulting uniform film may be applicable to various halide perovskite-based devices.

Halide-driven formation of lead halide perovskites: insight from ab initio molecular dynamics simulations

“…Illuminated precursor solutions show an increased amount of high-order iodoplumbates which allows uniform perovskite film formation with low defect density and high reproducibility. 32 34 These studies further highlight the relevance of a stable intermediate phase for the formation of a uniform and dense perovskite layer upon thermal annealing.…”

High‐purity synthesis of all‐inorganic CsPbBr 3 perovskite powder assisted by solubilizing organic ligand and its application to perovskite solar cells

“…However, the additional diffraction peak of CsPb 2 Br 5 appeared at 11.8 in the control film, indicating the generation of non-stoichiometry phase in perovskite films during the deposition using the metal halide precursor solution. On the other hand, the improved quality of perovskite film from LAPS powder may originate from a more efficient formation of complex 24 or plumbate 25 or both 26 during the solution preparation from pre-synthesized crystal. 27 The photophysical properties of CsPbBr 3 films prepared from different solutions were investigated using steady-state PL and time-resolved photoluminescence measurements.…”

The role of Pb oxidation state of the precursor in the formation of 2D perovskite microplates

“…Various strategies have been proposed to promote the formation of highly coordinated iodoplumbate complexes, including the use of weakly coordinating solvents, 35,36 increasing the Pb : I ratio in the solution, 37,38 incorporating I 3 − to the solution, 30 photo-induced HI dissociation 39 and irradiating of the precursor solution. 36 Similarly, controlling crystallisation of 2D LHPs has been done by adjusting the solvent 40,41 and organo-halide salt concentration, 42,43 while the role of inorganic-lead precursors has been mostly omitted.…”