Enhancing Carrier Transport Properties of Two-Dimensional Perovskite Cs₂PbI₂Cl₂ through Strain Engineering

Two-dimensional (2D) lead-halide perovskites have demonstrated significant potential in optoelectronic devices due to their enhanced stability and exceptional in-plane carrier mobility. To further promote the performance of Cs2PbI2Cl2 based optoelectronic devices, a strain engineering method is employed to tune the quantum transport properties of Cs2PbI2Cl2 in this work. In addition to investigating the effects of strain on the electronic and excitonic properties of Cs2PbI2Cl2 using density functional theory, we also examine the carrier transport characteristics through the nonequilibrium Green's function (NEGF) method. The variations of electron transmission, device density of states, effective potential, conductance, current-voltage characteristics, and photocurrent of pristine and strained Cs2PbI2Cl2 are compared by using a two-probe device model. The results indicate the compressive strain reduces the band gap, carrier effective mass, exciton binding energy, while enhancing the electron transmission and resulting in higher current. Additionally, we observe strain- and polarization-dependent cosine-like photocurrents under the illumination of linearly polarized light. This work establishes that strain is an effective approach to enhance the in-plane carrier transport properties of 2D Cs2PbI2Cl2.