Efficient Tin Perovskite Solar Cells via Suppressing Autoxidation in Inert Atmosphere

Abstract

The unsatisfactory power conversion efficiency (PCE) and long‐term stability of tin perovskite solar cells (TPSCs) restrict its further development as alternatives to lead perovskite solar cells (LPSCs). Considerable research has focused on the negative impacts of O2 and H2O, while discussions about degradation mechanism in an inert atmosphere remains insufficient. Herein, the light‐induced autoxidation of tin perovskite in nitrogen atmosphere is revealed for the first time and the elastic lattice distortion is demonstrated as the crucial role of rapid degradation. The continuous injection of photons induces energy transfer from excited A‐site cations to vibrating Sn–I framework, leading to the elastic deformation of perovskite lattice. Consequently, the over distorted Sn–I framework releases free iodine and further oxidizes Sn2+ in the form of molecular iodine. Through an appropriately designed light–dark cyclic test, a remarkable PCE of 14.41% is achieved based on (Cs0.025(MA0.25FA0.75)0.975) 0.98EDA0.01SnI3 solar cells, which is the record of hybrid triple TPSCs so far. The findings unveil autoxidation as the crux of TPSCs’ degradation in an inert atmosphere and suggest the possibility of reinforcing the tin perovskite lattice towards highly efficient and stable TPSCs.

Efficient quasi-2D tin perovskite solar cells based on mixed monoammonium and diammonium terminal molecules

“…The outstanding optoelectronic properties exhibited by tin perovskites, such as high absorption coefficients, low exciton binding energies and desirable bandgaps, render them as one of the most promising candidates for lead-free perovskites with a theoretical power conversion efficiency (PCE) of up to 33.4% based on the Shockley–Queisser equation. 1 Over the past decade, several seminal strategies have been employed to enhance the efficiency of tin perovskite solar cells (TPSCs) from approximately 6% to over 14%, 2–6 including compositional manipulation, 7–9 additive engineering, 10–13 surface modification 14,15 and device architecture design. 16–18…”