Photoelectrical Dynamics Uplift in Perovskite Solar Cells by Atoms Thick 2D TiS2 Layer Passivation of TiO2 Nanograss Electron Transport Layer

摘要

A deficiency in the photoelectrical dynamics at the interface due to the surface traps of the TiO_(2) electron transport layer (ETL) has been the critical factor for the inferiority of the power conversion efficiency (PCE) in the perovskite solar cells. Despite its excellent energy level alignment with most perovskite materials, its large density of surface defect as a result of sub lattice vacancies has been the critical hurdle for an efficient photovoltaic process in the device. Here, we report that atoms thick 2D TiS_(2) layer grown on the surface of a (001) faceted and single-crystalline TiO_(2) nanograss (NG) ETL have effectively passivated the defects, boosting the charge extractability, carrier mobility, external quantum efficiency, and the device stability. These properties allow the perovskite solar cells (PSCs) to produce a PCE as high as 18.73% with short-circuit current density (J _(sc)), open-circuit voltage (V _(oc)), and fill-factor (FF) values as high as 22.04 mA/cm~(2), 1.13 V, and 0.752, respectively, a 3.3% improvement from the pristine TiO_(2)-NG-based PSCs. The present approach should find an extensive application for controlling the photoelectrical dynamic deficiency in perovskite solar cells.