Removal of residual compositions by powder engineering for high efficiency formamidinium-based perovskite solar cells with operation lifetime over 2000 h

Abstract

Defects as a result of structural imperfections and/or extrinsic impurities in the perovskite films have a detrimental effect on efficiency and stability of perovskite solar cells (PSCs). Here, we propose to use pre-synthesized crystalline perovskite with perfect stoichiometry to control and lower the density of defects from precursors by the powder engineering method. Compared with raw materials (i.e., PbI 2 and FAI) based perovskites, the average efficiency of the PSCs fabricated based on these pre-synthesized perovskite precursors increased from 18.62% to 19.85%. Moreover, the unwanted intermediate chemical compositions (i.e., the unreacted phases and residual solvent) in the raw material-based perovskite films were significantly reduced in the pre-synthesized δ-FAPbI 3 and α-FAPbI 3 perovskites according to the secondary ion mass spectroscopy depth profiling results. Finally, we obtained the champion efficiency of 22.76% for α-FAPbI 3 and 23.05% for FAPb(I 0.9 Br 0.1 ) 3 based PSCs. Long-term operational stability measurements of the encapsulated FAPb(I 0.9 Br 0.1 ) 3 based PSCs showed a slow decay and maintained the efficiency about 88% after 1200 h (T 80 > 2000 h). Furthermore, a proof-of-concept integrated perovskite solar module-lithium ion battery-light-emitting diode device was demonstrated. Formamidinium-based perovskite solar cells with a high efficiency over 23% and 2000-h T 80 lifetime were fabricated using pre-synthesized crystalline perovskite powders via powder engineering. • Pre-synthesized crystalline perovskite powder with fewer defects is prepared by the powder engineering method. • Residual compositions are removed, which results in improved efficiency and operational stability. • The highest PCEs of 22.76% for α-FAPbI 3 and 23.05% for FAPb(I 0.9 Br 0.1 ) 3 are achieved by the powder engineering method. • A proof-of-concept perovskite solar module-lithium ion battery-light-emitting diode (PSM-LIB-LED) device is demonstrated.