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) 2 MA n -1 Pb n I 3 n +1 ( n ≥ 1) on regular filter paper with responsivity of 2.62 mA W −1 and response time (τ rise /τ decay ) 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.