Efficiency enhancement of Cs<inf>0.1</inf>(CH<inf>3</inf>NH<inf>3</inf>)<inf>0.9</inf>PbI<inf>3</inf> perovskite solar cell by surface passivation using iso-butyl ammonium iodide

Abstract

Efficiency enhancement of Cs0.1(CH3NH3)0.9PbI3 solar cell devices was performed by using iso-butyl ammonium iodide (IBA) passivated on Cs0.1(CH3NH3)0.9PbI3 films. The n−i−p structure of perovskite solar cell devices was fabricated with the structure of FTO/SnO2/Cs0.1(CH3NH3)0.9PbI3 (FTO, i.e. fluorine doped tin oxide) and IBA/Spiro-OMeTAD/Ag. The effect of different weights of IBA passivated on Cs-doped perovskite solar cells (PSCs) was systematically investigated and compared with non-passivated devices. It was found that the 5-mg IBA-passivated devices exhibited a high power conversion efficiency (PCE) of 15.49% higher than 12.64% of non-IBA-passivated devices. The improvement of photovoltaic parameters of the 5-mg IBA-passivated device can be clearly observed compared to the Cs-doped device. The better performance of the IBA-passivated device can be confirmed by the reduction of PbI2 phase in the crystal structure, lower charge recombination rate, lower charge transfer resistance, and improved contact angle of perovskite films. Therefore, IBA passivation on Cs0.1(CH3NH)0.9PbI3 is a promising technique to improve the efficiency of Cs-doped perovskite solar cells.