Giant Humidity Effect of 2D Perovskite on Paper Substrate: Optoelectronic Performance and Mechanical Flexibility.

Flexible optoelectronic devices have attracted enormous attention as an essential component in next‐generation wearable devices. To meet the trend of biocompatibility, flexibility and low cost, paper‐based optoelectronic devices have become compelling candidates. Moreover, 2D organic–inorganic metal halide perovskites have been extensively studied for the application in flexible optoelectronic devices owing to their long‐term moisture stability, optoelectronic tunability, and multiple quantum well (MQW) structures. Herein, the paper‐based flexible optoelectronic devices are designed by spin‐coating PEDOT:PSS and (iso‐BA)2MAn‐1PbnI3n+1 (n ≥ 1) on regular filter paper with responsivity of 2.62 mA W−1 and response time (τrise/τdecay) of 0.81/0.18 s at 35% relative humidity (RH). Furthermore, the responsivity may be increased by 250% within the humidity range from 35% to 90%, and remains above 92% of the initial value after measured for 1800 s at 60% RH. This work can pave the way for further studies about the humidity effect on perovskites for next‐generation green wearable electronics. [ABSTRACT FROM AUTHOR]