Electric-field assisted perovskite crystallization for high-performance solar cells

We develop an external-electric-field (EEF)-assisted annealing treatment to improve the photoelectric performance of planar organic-inorganic perovskite solar cells (PSCs). The new strategy can control the ion polarization orientation of perovskite films to obtain a good crystallization film and enhance the built-in electric field (BIF), which facilitates the effective promotion of charge separation and transport. Under an optimized treatment of up-EEF-assisted (2.5 V mu m(-1)) annealing, the power conversion efficiency (PCE) of the inverted PSC is improved from 15.33% to 17.26%, and from 16.77% to 19.18% for regular PSCs, compared with the thermal-annealing-only process. The ion polarization and ferroelectricity in the perovskite layer induced by the EEF are intensively discussed. The finding in this work provides a new route to improve perovskite film quality and cell performance.