Emergent Optoelectronic Properties of Mixed-Dimensional Heterojunctions

• DOI: 10.1021/acs.accounts.9b00581
• Publication Date: 2020-01-21T13:52:34Z
• Authors: Suyog Padgaonkar; Jack N. Olding; Lincoln J. Lauhon; Mark C. Hersam; Emily A. Weiss
• Keywords: Nanomaterials

ConspectusThe electronic dimensionality of a material is defined by the number spatial degrees confinement its wave function. Low-dimensional semiconductor nanomaterials with at least one degree have optoelectronic properties that are tunable size and environment (dielectric chemical) particular interest for applications such as light detection, harvesting, photocatalysis. By combining differing dimensionalities, mixed-dimensional heterojunctions (MDHJs) exploit desirable characteristics their components. For example, strong optical absorption zero-dimensional (0D) materials combined high charge carrier mobilities two-dimensional (2D) widens spectral response enhances responsivity photodetectors, which has implications ultrathin, flexible devices. MDHJs highly sensitive to (i) interfacial chemistry because large surface area-to-volume ratios (ii) electric fields, incompletely screened ultrathin nature MDHJs. This sensitivity presents opportunities control physical phenomena in through chemical modification, excitation, externally applied other environmental parameters. Since this fast-moving research area beginning pose answer fundamental questions underlie behavior MDHJs, it an opportune time assess progress suggest future directions field.In Account, we first outline characteristic properties, advantages, challenges low-dimensional materials, many arise result quantum effects. The performance primarily determined dynamics excitons carriers interfaces, where these particles tunnel, trap, scatter, and/or recombine on scales tens femtoseconds hundreds nanoseconds. We discuss several photophysical deviate from those observed bulk heterojunctions, well factors can be used vary, probe, ultimately MDHJ systems. then namely, photovoltaics, photocatalysts, identify current limits compared state-of-the-art benchmarks. Finally, strategies extend understanding toward realization stimuli-driven responses, particularly respect exciton delocalization, emission, morphology, external stimuli, spin selectivity, usage chemically reactive materials.