From BiI3 to CuBiI4: a Striking Improvement in Photoelectric Performance as a Novel Photodetector Candidate
Bismuth halide based semiconductors attract increased attention as the next generation photodetectors because of their excellent photoelectric performance, environmental-friendly and high-element-abundance characteristics. However, it is still challenging to prepare such a thin film in normal surrounding condition because of the instability character of BiI3. In this work, we use a room temperature elemental powder reaction in ambient for easy preparation of Cu incorporated perovskite-like CuBiI4 in large-scale. The crystalline and photoelectric characteristics of the resulting CuBiI4 thin films started from different Cu content have been investigated by X-ray diffraction (XRD), UV-Vis spectroscopy, photoluminescence spectroscopy (PL) and transient surface photovoltage (TSPV). The CuBiI4 based photodetectors are firstly assembled, which show a striking improvement in responsivity of photodetectors compared with pure binary BiI3. Especially, the responsivity of the photodetector started with 1 : 1 molar ratio of copper and bismuth reaches 106 times larger than that with 0 : 1 initial molar ratio (pure BiI3). The possible mechanism for such an improvement was preliminarily discussed by taking advantage of the Hall Effect measurements. Our work not only provides a universal synthetic strategy for preparing high quality Bi based perovskite-like photoelectric materials, but also presents a novel Bi based photodetector materials.