Chemical stabilities of hybrid perovskites demand further improvement for long-term and large-scale PV applications. Herein, we report enhanced stability of MAPbI3 by doping divalent Se2- in the form of PbSe in precursor solutions to enhance the hydrogen-bonding-like interactions between CH3NH3+ and inorganic framework, as evidenced by redshifted N-H stretch from infrared spectra. In 100% humidity, the 10% w/w PbSe-doped MAPbI3 films exhibited &gt;140-fold stability improvement over pristine MAPbI3 film. A top efficiency of 10.4% with 70% retention after 700 hours aging in ambient air was achieved on an unencapsulated 10% w/w PbSe:MAPbI3 cell. Significantly, incorporated Se2- effectively suppressed iodine diffusion in solar cell, leading to enhanced stability of the silver electrodes. Successful doping of divalent Se2- in perovskite lattice is further confirmed by enlarged lattice spacing from XRD patterns, asymmetric photoluminescence peaks with intra-gap states, and concomitantly increased electrical conductivity of 5%, 10% w/w PbSe:MAPbI3 thin films. This work could advance the fundamental understanding of degradation and stabilization of hybrid perovskites in both material and device settings.

Chalcogenide doping in hybrid perovskites for enhanced stability of solar cells

2019 Spring National Meeting

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