Structural and Optical Studies of GaAs1-xBix and 􀉴􀍲Bi2O3 for optoelectronic devices.

Last year, researchers from KU Leuven realised a Ag nanocluster-embedded zeolite (Ag-zeolite) system exhibiting near-perfect efficiency for UV to VIS down-conversion (quantum yield, QY= 1), providing a cost-effective and environmentally friendly solution to lowering our reliance on a shorting supply of rare-earth phosphors. This result was achieved for a single Ag-zeolite assembly type and the exact nature of its absorptive and emissive mechanisms remains unknown. To rationalise this discovery, this project aims to build a comprehensive understanding of the optical properties of Ag-zeolites which display high QYs. Due to a tendency of Ag-zeolites to degrade when exposed to high-energy analytical probes, an holistic characterisation approach will be sought; namely the combination of high-resolution transmission electron microscopy, extended Xray absorption fine structure, electron spin resonance and deep-UV Raman studies (aided by theoretical calculations) performed on an instrument designed by the applicant. State-of-the-art structural data will be used to reveal the correlation between Ag-zeolite structure and electronic properties, at an atomic level, permitting computer simulations of the electronic structure leading to high QYs and the clear identification of absorptive and emissive centres. By isolating internal environments which manifest high QYs, rational design protocols will be developed for Ag-zeolite materials possessing efficient optical down-conversion.