A Perylene‐Based Conjugated Polymer Endows Perovskite Solar Cells with 85 °C Durability: The Control of Gas Permeation

Abstract

Abstract Organic–inorganic hybrid perovskites in high‐efficiency solar cells are prone to degradation at elevated temperatures, especially in the presence of water moisture. A hole‐transporting conjugated copolymer (abbreviated as p‐NP‐E) characteristic of alternating N ‐annulated perylene and 3,4‐ethylenedioxythiophene backbones, to achieve thermostable perovskite solar cells (PSCs) via controlling gas permeation and thus perovskite decomposition is reported. p‐NP‐E can be conveniently prepared via Pd‐catalyzed direct arylation polycondensation. The air‐doped p‐NP‐E composite film containing nonvolatile 4‐ tert ‐butylpyridinium bis(trifluoromethanesulfonyl)imide presents a higher hole mobility and an improved conductivity in comparison with the control based on the state‐of‐the‐art polymer, p‐TAA, leading to more efficient PSCs. More critically, the p‐NP‐E based hole transport layer is not only morphologically more heat‐resistant, but also features a lower solubility coefficient and diffusion coefficient of both environmental water molecules and gaseous products such as CH 3 I and CH 3 NH 2 from the thermal decomposition of perovskite, enabling the fabrication of 21.7%‐efficiency, 85 °C durable solar cells.