Bio-inspired materials as interfacial layers for high performance perovskite photodetectors
Achieving an optimal performance from a perovskite photodetector requires its internal interfaces to be suitably engineered. In this type of photodetector, a perovskite thin film absorbs the incident photons and converts them into photo-generated electrons and holes. Two charge-selective layers sandwiching the perovskite separate the two types of charges, thus promoting their extraction at two different electrodes to generate a current. In this context, the interfaces between the perovskite and the charge-selective layers have a special impact on the value of the generated current, so that they play a pivotal role in the photodetector performance. This is well illustrated by Zhan Gao and coworkers, who show that adding biomolecules such as DNA or guanine at the perovskite/PCBM interface of their ITO/PEDOT:PSS/MAPbI3 perovskite/PCBM/Ag photodetectors eases electron extraction. The thereby improved photodetectors generate a stronger current (and thus present a higher responsivity and detectivity) than reference devices without biomolecules. These biomolecules take a particular advantage in comparison to other reported interfacial materials because of their low cost, being hundreds of times cheaper than graphene.