Fabricating stable and efficient perovskite solar cells in air ambient via lattice anchoring strategy

Abstract

The stability issue is becoming more and more important in the development of halide perovskite solar cells (PSCs). Various strategies have been adopted to explore the stability of perovskite films and devices. Nevertheless, most perovskite films are prepared in inert atmosphere, limiting the practical application of PSCs. Herein, lattice anchoring strategy was employed to prepare stable perovskite films in air ambient. The adopted bidentate anchor cations (BACs) could effectively inhibit the invasion by moisture and restrain organic component escaping from perovskite structure during preparation process. The steric and coulomb effects of embedded BACs have dual influence on the crystal growth process and morphology of perovskite films. The BACs are pinned on the crystal lattices and the surface of perovskite film without forming 2D perovskite, which would enhance the crystal intrinsic stability and moisture resistance. The modified CH3NH3PbI3 device power conversion efficiency (PCE) raises to 20.33%, and remains over 85% of the initial PCE during exposure to ambient air (humidity＞70 RH, temperature＞30 °C) for over 90 days. The lattice anchoring strategy provides a convenient method to improve the quality of perovskite films in air ambient.