RESUMEN
The wettability of precursor solution on substrates is the critical factor for fabricating quality film. In this work, superwetting nanofluids (NFs) of non-stoichiometric nickel oxide (NiOx) nanocrystals (NCs)-CsBr solution are first utilized to fabricate quality NiOx-CsPbBr3 hybrid film with gradient-distributed NiOx NCs in the upper part for constructing hole transport ladder in carbon-based perovskite solar cells (C-PSCs). As anticipated, the crystalline properties (improved crystalline grain diameters and reduced impurity phase) and hole extraction/transport of the NiOx-CsPbBr3 hybrid film are improved after incorporating NiOx NCs into CsPbBr3. This originates from the superb wettability of NiOx-CsBr NFs on substrates and the excellent hole-transport properties of NiOx. Consequently, the C-PSCs with the structure of FTO/SnO2/NiOx-CsPbBr3/C displays a power conversion efficiency of 10.07%, resulting in a 23.6% improvement as compared with the pristine CsPbBr3 cell. This work opens up a promising strategy to improve the absorber layer in PSCs by incorporating NCs into perovskite layers through the use of the superwettability of NFs and by composition gradient engineering.
RESUMEN
The performance of low-temperature carbon-based perovskite solar cells (C-PSCs) with high commercial potential was hampered by the inferior interface between the absorber and carbon electrode. In this work, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) was dissolved in an antisolvent for spin-coating perovskite (CH3NH3PbI3, MAPI) films, which was applied to modify both the MAPI films and the interface between the MAPI layer and carbon electrode by gradient engineering. Finally, the C-PSCs based on MAPI-PTAA gradient bulk heterojunction films achieved a power conversion efficiency of 13.0% with an active area of 1 cm2, 26% higher than that of pristine MAPI cells, because of the passivated trap states, accelerated hole extraction, and improved crystalline properties in absorber films.