Divalent Anionic Doping in Perovskite Solar Cells for Enhanced Chemical Stability.

Gong, Jue; Yang, Mengjin; Rebollar, Dominic; Rucinski, Jordan; Liveris, Zachary; Zhu, Kai; Xu, Tao · Adv Mater · 2018

basic_science · Level V

Where this comes from

Abstract

The chemical stabilities of hybrid perovskite materials demand further improvement toward long-term and large-scale photovoltaic applications. Herein, the enhanced chemical stability of CH<sub>3</sub> NH<sub>3</sub> PbI<sub>3</sub> is reported by doping the divalent anion Se<sup>2-</sup> in the form of PbSe in precursor solutions to enhance the hydrogen-bonding-like interactions between the organic cations and the inorganic framework. As a result, in 100% humidity at 40 °C, the 10% w/w PbSe-doped CH<sub>3</sub> NH<sub>3</sub> PbI<sub>3</sub> films exhibited >140-fold stability improvement over pristine CH<sub>3</sub> NH<sub>3</sub> PbI<sub>3</sub> films. As the PbSe-doped CH<sub>3</sub> NH<sub>3</sub> PbI<sub>3</sub> films maintained the perovskite structure, a top efficiency of 10.4% with 70% retention after 700 h aging in ambient air is achieved with an unencapsulated 10% w/w PbSe:MAPbI<sub>3</sub> -based cell. As a bonus, the incorporated Se<sup>2-</sup> also effectively suppresses iodine diffusion, leading to enhanced chemical stability of the silver electrodes.