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

Abstract

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 ∼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.