Publications by authors named "W A Tisdale"
Halide perovskites have emerged as promising materials for a wide variety of optoelectronic applications, including solar cells, light-emitting devices, photodetectors, and quantum information applications. In addition to their desirable optical and electronic properties, halide perovskites provide tremendous synthetic flexibility through variation of not only their chemical composition but also their structure and morphology. At the heart of their use in optoelectronic technologies is the interaction of light with electronic excitations in the form of excitons.
View Article and Find Full Text PDFSinglet exciton fission has the potential to increase the efficiency of crystalline silicon solar cells beyond the conventional single junction limit. Perhaps the largest obstacle to achieving this enhancement is uncertainty about energy coupling mechanisms at the interfaces between silicon and exciton fission materials such as tetracene. Here, the previously reported silicon-hafnium oxynitride-tetracene structure is studied and a combination of magnetic-field-dependent silicon photoluminescence measurements and density functional theory calculations is used to probe the influence of the interlayer composition on the triplet transfer process across the hafnium oxynitride interlayer.
View Article and Find Full Text PDFAlloying is a powerful strategy for tuning the electronic band structure and optical properties of semiconductors. Here, we investigate the thermodynamic stability and excitonic properties of mixed-chalcogen alloys of two-dimensional (2D) hybrid organic-inorganic silver phenylchalcogenides (AgEPh; E = S, Se, Te). Using a variety of structural and optical characterization techniques, we demonstrate that the AgSePh-AgTePh system forms homogeneous alloys (AgSeTePh, 0 ≤ ≤ 1) across all compositions, whereas the AgSPh-AgSePh and AgSPh-AgTePh systems exhibit distinct miscibility gaps.
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- Fermi resonance is a phenomenon where two similar vibrational or electronic states mix, and this study explores this in atomically thin black phosphorus, a material that hasn't been thoroughly investigated in this context.
- The study reveals that the Fermi resonance occurs through the mixing of a fundamental Raman mode and a related infrared mode, resulting in a characteristic doublet that changes with applied strain.
- The findings provide new insights into how electrons interact with vibrations (or phonons) in black phosphorus and suggest a new way to control Fermi resonances in two-dimensional semiconductor materials.