Tailoring Interface and Surface Chemistry Toward Stable and Efficient Photovoltaics and Optoelectronics

Alongside improvements in synthesis, theory has long played a crucial role in advancing optoelectronic materials and devices. In this talk, I will introduce a novel strategy to promote phase growth and stabilize the favorable phase in hybrid halide perovskites via fine-tuning interface energetics. Building upon our previous works in surface and interface modification strategies, we investigate the complex surface and interface interactions that occur during deposition and growth, critical to understanding device performance. Performing rigorous quantum mechanical modeling, we develop a phase growth model for formamidinium lead iodide (FAPbI3) that predicts the phase-stability crossover. We uncover the crucial role of ligand migration contingent upon the presence of excess capping ligands in cubic phase stabilization. I will showcase our study on the importance of surface characterization and dynamics on photoluminescence intermittency, one of the biggest challenges in realizing scalable single photon emitters based on inorganic perovskite quantum dots. By unfolding the complex ligand equilibrium and surface phenomena, we provide guidelines for designing efficient and scalable devices. Our research emphasizes the importance of surface and interfacial characterization, and molecular design in advancing the next generation of optoelectronic devices.