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Erik Grumstrup - Montana State University

Abstract:

Functional materials that fall outside the realm of traditional solid state physics are promising platforms for optoelectronic applications in a variety of arenas – from catalysis to solar energy conversion to quantum information. While promising, these “disordered” materials pose an enormous challenge to those seeking to understand and ultimately exploit their electronicproperties. Because these materials are often soft and have strong molecular-like character, their electronic structure, and therefore their functionality, is highly sensitive to both static and dynamic structural disorder. On the other hand, this sensitivity to the local electronic structure means that synthetic chemistry can provide a powerful approach for tuning material function. I’ll discuss recent work in my group utilizing time-resolved spectroscopies and microscopies to disentangle the effects of structural and compositional disorder in complex materials that lie somewhere between the molecular and semiconductor limits. In particular, I’ll describe efforts that use correlative microscopies to determine how disorder affects ambipolar electron-hole transport in lead halide perovskites. I’ll also discuss some recent work elucidating charge transfer and exciton transport processes in organic perylene diimide assemblies and the photocatalyticmaterial graphitic carbon nitride. While diverse projects, the underlying theme in these systemsis that materials are intrinsically heterogeneous, and an accurate understanding of how they behave requires approaches that account for this heterogeneity.