Self-powered and flexible perovskite photodiode/solar cell bifunctional devices with MoS_2 hole transport layer

摘要

Hybrid organic-inorganic perovskites are highly attractive for the use in optoelectronic devices, but their instabilities should be solved before the practical applications. As one of the solutions, it is important to find a transport layer that can improve the stability and durability of the devices. Here, we first employ MoS2 for a hole transport layer (HTL) in high-performance flexible p-i-n-type perovskite photodiode (PD)/solar cell bifunctional devices (PPSBs) with co-doped graphene transparent conductive electrodes. The current of the PPSB increases by up to 10(6) times by illumination even at 0 V, meaning "self-powered". The PPSB exhibits high responsivity and on/off ratio in a broad spectral range of ultraviolet to visible light at a PD mode and good photovoltaic properties at a solar cell mode. The photoresponse shows only 38% degradation during 30 days, and the photo-stability is almost perfect under continuous light soaking for 100 h. Flexible PPSB exhibits excellent mechanical properties by maintaining similar to 57% of its initial photocurrent even after 3000 bending cycles at a curvature radius of 4 mm. These results suggest that MoS2 films can be successfully used as a HTL in perovskites-based rigid/flexible optoelectronic devices.