Ultrafast Quasi-2D/3D Perovskite Photodetectors Conferred Using Interfacial Engineering of Self-Assembled Monolayers

Quasi-2D (q-2D) perovskites are extensively studied due to their hybrid properties of 3D and 2D phases and have proven to be applied to a wide range of optoelectronics. Multiple device engineering methods for perovskite photodetectors are developed. However, the treatment of self-assembled monolayer (SAM) is rarely discussed. Herein, a series of silane-coupling agents of (3-chloropropyl)trichlorosilane (CPTS), phenyltrichlorosilane, and (3-aminopropyl)triethoxysilane is adopted as SAM materials and elucidated their influence on q-2D/3D CsPbBr3 films and their photodetector performance. The optical properties and morphology results reveal that perovskite film on CPTS-modified surface can prolong excitons' lifetime, produce a larger grain size and better size distribution, while also present better crystallinity and united orientation. As for the fabricated photodetectors, the device on a CPTS-modified surface has the highest photocurrent of 5.46 x 10-8 A, a responsivity of 0.16 A W-1, and an 18-times-higher specific detectivity than the pristine counterpart, which comes from the higher surface energy and favorable energy level alignment. The photodetector on the CPTS-modified surface also shows better stability than that on the pristine surface. This study pioneers by using SAMs on q-2D perovskite photodetectors and provides a facile route of device fabrication for perovskite photodetectors. A series of silane-coupling agents are applied on the silicon wafer surface to modify the morphology and photodetector performance of quasi-2D CsPbBr3 films. The photodetector on the (3-chloropropyl)trichlorosilane-modified surface shows larger crystallite size, prolonged exciton lifetime, and better stability than that on the pristine surface. This study pioneers a facile route of device fabrication for perovskite photodetectors. image