Research Projects

Metal halide perovskites (MHPs) hold immense promise for sustainable chemistry, with tunable bandgaps (1.5–3 eV), strong light absorption, and long charge carrier diffusion lengths. These properties have made them frontrunners in photovoltaics, yet their potential in photocatalysis remains underexploited due to a critical weakness: their ionic lattice (ABX3, X = Cl, Br, I) rapidly degrades in the presence of moisture, light, and reactive species, making them incompatible with aqueous catalytic systems essential for scalable green chemistry. The overarching goal of this project is to transform metal halide perovskites (MHPs) from water-sensitive nanomaterials into robust, tunable, and catalytically competent platforms for real-world applications in solar-driven chemistry and optoelectronics. While we have previously achieved significant progress in stabilizing CsPbBr3 nanocrystals in water using rationally designed ligands, the next frontier, and the core challenge addressed in this proposal, is to generalize this aqueous stability across MAPbBr3, FaPbBr3, CsPbCl3, CsPbI3, and mixed-halide systems, each with distinct chemical and structural complexities. The challenge lies in the differing surface chemistries, lattice softness, and defect landscapes of these perovskites. CsPbCl3 suffers from deep trap states and a wide bandgap; CsPbI3 exhibits severe octahedral tilting and phase instability; and mixed-halide systems are prone to segregation. Our objective is to develop a modular ligand framework with multidentate, amphiphilic, and environmentally responsive features that can adaptively bind across halide compositions and impart long-term colloidal and structural stability in water. We will probe how halide composition and ligand passivation influence trap density, band edge energetics, and charge carrier dynamics using a suite of optical and electrochemical tools. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and time-resolved methods (TCSPC, transient absorption) will reveal how surface chemistry controls recombination and interfacial charge transfer, parameters essential for both catalysis and device applications. The stabilized perovskites will be deployed in photocatalytic transformations in aqueous media, focusing on CO2 reduction to C1–C3 hydrocarbons and nitrate-to-ammonia conversion. These multielectron processes will be performed in custom photoreactors, and product analysis will rely on high-sensitivity gas chromatography (GC), enabling quantitative correlation between material design and catalytic efficiency. Doping with Cu, Ni, Pt, or Pd will further tune activity and selectivity. In parallel, we will explore light-driven organic reactions, including aerobic oxidation and heterocyclization, using water as a green solvent. To extend the utility of these materials, we will also collaborate with experts to evaluate their integration into photoelectrochemical and optoelectronic device architectures, where moisture stability is critical. This project aims to establish a scalable strategy for stabilizing MHPs in aqueous conditions across compositions. If successful, it will deliver a new class of functional nanomaterials that combine spectral tunability, catalytic activity, and environmental resilience, paving the way for sustainable solar fuels, green synthesis, and next-generation photovoltaic technologies.