Kilogram-scale high-yield production of PbI₂ microcrystals for optimized photodetectors

Exploring a new material with optoelectronic properties and studying its phonon and photon properties are of great value for practical applications. Herein, we demonstrate a photodetector based on layered PbI2 microcrystals synthesized using a high-yield production strategy. The temperature-dependent Raman study further reveals a redshift of phonon frequencies with an increase in temperature. Both symmetric Au-PbI2-Au and asymmetric Au-PbI2-Graphene photodetectors were fabricated for comparing their photoresponse performance. Owing to the high Schottky barrier near Au electrodes, the symmetric Au-PbI2-Au photodetector exhibited a low dark current of similar to 0.4 pA at 10 V. In contrast, the substitution of one Au electrode with graphene offered a smooth van der Waals contact with PbI2, contributing to a 3-4.8 fold increase in photocurrent compared with the Au-PbI2-Au photodetector under the same light intensity.