Er-doped Cs2AgBiCl6 double perovskite large single crystal for optoelectronics

Double perovskites have shown great potential in addressing the toxicity and instability concerns of lead halide perovskites for practical applications. However, the fabrication of high-quality double perovskite single crystals has remained challenging. Here, large Er-doped Cs2AgBiCl6 single crystals (SCs) with a maximum dimension of 8 mm were successfully prepared using a solution temperature-lowering (STL) method. The photoluminescence (PL) spectra were excited by the lasers with energies below and above the band gap, and the origin of the abnormal PL peaks changing with temperature is explored. The photodetector made from the Er-doped Cs2AgBiCl6 SCs shows a significantly enhanced light responsivity and detectivity in the wavelength range from 370 nm to 660 nm compared with the undoped one, with excellent environmental and radiation stability. It reveals that the Er ions can be successfully doped into double perovskite single crystal, benefiting the application to optoelectronic devices.