Charge Carrier Dynamics in Chiral 2D/3D Halide Perovskites

The surface modification of 3D halide perovskites with quasi-two-dimensional (2D) heterostructures has become ubiquitous in photovoltaics to achieve high power conversion efficiencies (PCEs) in tandem and single junction devices. Recent studies have demonstrated that 2D hybrid organic-inorganic perovskites (HOIPs), when integrated with chiral organic ligands, exhibit spin polarization through the chiral-induced spin selectivity (CISS) effect. This spin-polarized charge carrier transport can propagate over hundreds of nanometers. In this work, we aim to leverage the CISS effect in chiral 2D HOIPs as interlayers within 3D perovskite matrices, with the goal of reducing surface recombination and enhancing charge collection in the transport layers of photovoltaic devices. To measure charge mobility and investigate the influence of chirality on carrier diffusion in perovskites, we utilize optical pump terahertz probe (OPTP) spectroscopy. The goal is to determine whether carrier diffusion is faster in chiral perovskites, which exhibit a preferred emission direction, compared to non-chiral perovskites that lack such directional preference.