Photoconduction in 2D Single‐Crystal Hybrid Perovskites

Abstract

Single‐crystal hybrid perovskites represent an emerging class of next‐generation semiconductors due to their excellent and tunable optoelectronic properties, along with a solution‐based, low‐temperature growth process. 2D single‐crystal hybrid perovskites are especially promising as their long‐range ordered multiple quantum well structure induces many peculiar properties, such as large exciton binding energy, large in‐plane conductivity, and improved environmental stability, which make them suitable for low‐dimensional optoelectronics applications and fundamental studies. Herein, the structural properties, morphology, and optoelectronic behavior of 2D thin film phenethylammonium lead iodide (PEA2PbI4) single‐crystals, synthesized using the space‐confined growth technique are explored. A planar device is fabricated and its spectral photoresponse is studied under broadband supercontinuum white light. Remarkably, the device exhibits an ultra‐low dark current (10−14 A), indicative of low defect density and suppressed ion migration. Under white light, the current increases linearly with the incident power, up to a factor of 105, and the device achieves a specific detectivity of 109 Jones. The temperature and wavelength dependence of the photocurrent suggests the dissociation of excitons as one of the main mechanisms affecting photoconduction. Furthermore, stability under air exposure and illumination turns out to be remarkable.