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

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 NH PbI is reported by doping the divalent anion Se 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 NH PbI films exhibited >140-fold stability improvement over pristine CH NH PbI films. As the PbSe-doped CH NH PbI 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 -based cell. As a bonus, the incorporated Se also effectively suppresses iodine diffusion, leading to enhanced chemical stability of the silver electrodes.