Electroluminescence and photo-response of inorganic halide perovskite bi-functional diodes

In this work, we report our efforts to develop a novel inorganic halide perovskite-based bi-functional light-emitting and photo-detecting diode. The bi-functional diode is capable of emitting a uniform green light, with a peak wavelength of 520 nm, at a forward bias of >2 V, achieving a high luminance of >103 cd/m2 at 7 V. It becomes an efficient photodetector when the bi-functional diode is operated at a reverse bias, exhibiting sensitivity over a broadband wavelength range from ultraviolet to visible light. The bi-functional diode possesses very fast transient electroluminescence (EL) and photo-response characteristics, e.g. with a short EL rising time of ~6 μS and a photo-response time of ~150 μS. In addition, the bi-functional diode also is sensitive to 520 nm, the wavelength of its peak EL emission. The ability of the bi-functional diodes for application in high speed visible light communication was analyzed and demonstrated using two identical bi-functional diodes, one performed as the signal generator and the other acted as a signal receiver. The dual functions of light emission and light detection capability, enabled by bi-functional diodes, are very attractive for different applications in under water communication and visible light telecommunications.