Enhanced electron transport induced by a ferroelectric field in efficient halide perovskite solar cells

• Published in: Solar energy materials and solar cells 2020-03, Vol.206, p.110318, Article 110318
• Main Authors: Zarenezhad, Hamaneh, Askari, Masoud, Halali, Mohammad, Solati, Navid, Balkan, Timucin, Kaya, Sarp
• Format: Article
• Language: English
• Subjects: Difluorides; Dipoles; Electron transport; Energy conversion efficiency; Fabrication; Ferroelectric; Ferroelectric materials; Ferroelectricity; Grain size; Halide perovskite solar cells; Morphology; Perovskites; Photovoltaic cells; Photovoltaics; Polymer additive; Polymers; Polyvinylidene fluorides; PVDF; Solar cells
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2019.110318

Perovskite solar cells have been appearing as a superior photovoltaic device owing to their high photovoltaic performance and low cost of fabrication. The formation of a compact and uniform perovskite layer with large crystal size is a significant factor to get the best device performance. In this work, polyvinylidene difluoride (PVDF) was used as a ferroelectric polymer additive to fabricate high-performance mesoporous CH3NH3PbI3-xClx mixed-halide perovskite solar cells in a sequential deposition method. Power conversion efficiency has been enhanced from 10.4 to 16.51% in an ambient atmosphere in the presence of an optimized amount of PVDF assuring continuous and smooth layers with large grain size. Besides morphological improvements, this progress in the photovoltaic performance is attributed to the dipole field exerted by PVDF that leads to enhanced charge separation. Further improvements in efficiency (18.60%) have been achieved by directing the dipoles under an external field. •Ferroelectric polymer additives (PVDF) significantly increase the PCE of mixed halide perovskite solar cells.•18.6% efficiency is reached after directing dipoles by external bias.•The enhancement is associated with both morphological smoothness and the local dipole field.•Ferroelectric polymer promotes efficient electron extraction and the lower charge carrier recombination.•The electron transfer layer/perovskite interface is very critical.