Elimination of Yellow Phase: An Effective Method to Achieve High Quality HC(NH2 )2 PbI3 -based Perovskite Films.
ChemSusChem
; 13(5): 956-963, 2020 Mar 09.
Article
en En
| MEDLINE
| ID: mdl-31849185
ABSTRACT
Formamidinium lead iodide-based (FAPbI3 ) perovskite is widely used in the field of photovoltaics, owing to its suitable bandgap (ca.â
1.45â
eV) and better thermal stability. FAPbI3 has two polymorphs (black α-FAPbI3 and yellow δ-FAPbI3 ) at ambient temperature. The yellow δ-FAPbI3 , which has no photoactivity, has a chain-like structure that likely hinders electron transport and reduces photovoltaic performance. However, pure-phase black α-FAPbI3 without any yellow phase is difficult to obtain and the underlying mechanism of the phase transition is rarely investigated. In this study, a facile bi-additive method (BA method) has been developed to completely eliminate the yellow δ-FAPbI3 phase by inducing a phase transition from δ-FAPbI3 to α-FAPbI3 . HI and Pb(SCN)2 were employed as dual additives. Based on the investigation of the annealing time and temperature, we determined that the BA method can induce the phase transition and enhance the stability of α-FAPbI3 . Owing to the enhanced crystallization as well as uniform morphology of the BA film, the perovskite solar cells (PSCs) exhibited an increased power conversion efficiency (PCE). Furthermore, the optimal devices displayed excellent stability and maintained over 80 % of initial PCE after aging for 400â
h in air. This work provides a new insight into the fabrication of high-quality pure α-FAPbI3 perovskite films and makes high efficiency photovoltaic devices a reality.
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MEDLINE
Idioma:
En
Revista:
ChemSusChem
Asunto de la revista:
QUIMICA
/
TOXICOLOGIA
Año:
2020
Tipo del documento:
Article