A Sensitive UV Photodetector Based on Non-Wide Bandgap MAPbBr₃ Nanosheet

A sensitive ultraviolet photodetector (UVPD) based on an ultrathin MAPbBr3 nanosheet was developed in this study. A simulation based on technology computer-aided design showed that the optical absorption of MAPbBr3 can be tailored by changing the material thickness, which is reasonable considering the wavelength dependence of the absorption coefficient of MAPbBr3. In addition, an apparent blueshift of the position of the maximum photocurrent is observed upon decreasing the nanosheet thickness. These tunable optoelectronic properties resulted in a device fabricated from medium-bandgap 43-nm-thick MAPbBr3 nanosheets being sensitive to UV light illumination. The device has a maximum photoresponse at 300 nm, a responsivity of 27.2 mA $\cdot \text{W}$ −1, and a response speed of 0.103/0.087 s, respectively, which are comparable to conventional UVPDs based on low-dimensional wide bandgap materials (e.g., ZnO and TiO2). This novel UVPD has application potential to optoelectronic systems.