Semiconductors have become an indispensable part of modern society. In particular, their remarkable ability to harness light for the generation of highly energetic electrons has opened up a plethora of applications in the energy sector, such as photovoltaics, photocatalysts, and photodetectors. A diverse spectrum of novel functional materials, including metal oxides, metal nitrides, and halide perovskites, offer an extensive array of physical and chemical properties that can be fine-tuned to serve specific purposes. 

Established in August 2021, the Jiang research group aspires to unravel the intricate life cycle of photogenerated charge carriers in these materials down to the atomic level. Taking photoelectrochemical energy conversion as an example (see the graphic below), semiconducting photoelectrodes can harvest abundant solar energy and catalyze redox reactions, producing chemical fuels for storage. However, this potential is compromised as the photoexcited charge carriers may interact with the lattice, leading to undesirable recombination events that diminish energy conversion efficiency. 

The dynamical interplay between electrons and lattice unfolds across broad spatial and time scales. To tackle this multifaceted challenge, we have adopted a holistic research approach bolstered by a multidisciplinary toolkit. We first start synthesizing thin films of novel semiconductors with well-controlled phase purity, defect concentration, and crystallographic orientation. Subsequently, the functional characteristics of these materials are investigated in-depth by electrochemical methods. Furthermore, the interactions between photoexcited charge carriers and the material are unveiled through time-resolved spectroscopic techniques. Our overarching goal is to identify the pivotal pathways where energy losses occur within the existing material systems. With the acquired knowledge, we aim to develop next-generation solar energy conversion devices with improved efficiencies. 

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