Loosening effect of perovskite intermolecular exchanger with strong steric hindrance for highly sensitive photodetector

Abstract

In this study, chloronaphthalene (CN) with unique physicochemical properties is incorporated in perovskite nucleation environment to fabricate high-quality photosensitive layer. Specifically, CN has a high boiling point and a bulky naphthalene ring, which induces a steric hindrance in the perovskite adduct phase. Thus, CN delays intermolecular interactions and promotes a stable nucleation environment, which provides sufficient time for the perovskite grains to grow. This is the loosening effect by CN. In this context, this results in the formation of enlarged grains with higher crystallinity for the CN-treated film, based on the LaMer model. According to the increased grain size, the length of grain boundaries which are the pathways to cause ohmic shunt get longer, resulting higher shunt resistance. As a result of the suppressed ohmic shunt and lower dark current density, the outstanding photodetector performance, especially detectivity was confirmed. Through LDR analysis, the possibility of applications under various light conditions was demonstrated. Moreover, better charge transfer and recombination properties were confirmed by PL and impedance analysis. As a result of observing the photodetector parameters for about 1000 h, improved device stability was proved.