Solution processed and highly efficient UV-photodetector based on CsPbBr3 perovskite-polymer composite film

Abstract

All inorganic cesium lead bromide (CsPbBr3) perovskite is being extensively applied to optoelectronics due to its facile solution processability and extraordinary optical properties. However, the expansion of its implementation in optoelectronic devices is being hindered due to the poor surface coverage of its film, inefficient charge transportation, long-term instability, and requirements of complex fabrication techniques. Here, a facile solution-processed composite perovskite film composed of CsPbBr3 polycrystals merged with polymers such as polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) has been introduced to act as a light absorber for efficient ultraviolet (UV) light detection. The as-used polymers in the composite film have improved the surface coverage, surface passivation, light absorption, stability, charge carrier lifetime due to the high UV-Absorption tendency of CsPbBr3 and transport capability strengthened by the good ionic conduction of PEO, which results in an efficient UV-photodetection. Compared to the pristine CsPbBr3 film-based PD, the CsPbBr3-polymer based PD has achieved a high photo-to-dark current ratio, responsivity and specific detectivity of up to 106, 55.71 AW−1 and 8.07 × 1013 Jones, respectively, at a very low bias voltage of 0.2 V using 365 nm light source. The device has shown excellent stability of over 3 weeks under ambient environmental conditions.