UC Merced

Hybrid perovskite materials are an emergent class of materials that display optical and electronic qualities highly favorable to solar device applications. Their affordability combined with high efficiencies have propelled them to the forefront of modern solar energy research. This dissertation investigates the unique optical properties of perovskite thin films and perovskite-based quantum dots using a variety of spectroscopy methods to demonstrate their potential for a variety of solar device applications, particularly luminescent solar concentrators (LSCs).

LSCs are a low-cost, design-friendly alternative to traditional solar cells that typically consist of a fluorescent material atop a high refractive index that absorbs incident light and re-emits it at a lower energy, acting as a waveguide for the down-shifted sunlight to its edges, where a solar cell is attached. Perovskites make excellent candidates for LSCs due to their high quantum yield, large refractive index and large Stokes shift. We optimize the halide content and thickness of perovskite thin films to yield devices reaching a maximum optical efficiency of 34.7% for 1.5cm x 1.5cm samples.

Additionally, we investigate the effects of coupling between perovskite quantum dots and plasmonic gold nanoparticles to illuminate the nature of this interaction. The collective resonance of free electrons in metallic nanoparticles can couple with the electron-hole pair in an excited semiconductor and lead to a number of fascinating phenomena. We perform photoluminescence and lifetime measurements on perovskite quantum dots in contact with gold nanoparticles of varying sizes, which result in emission enhancement for smaller nanoparticles.

These results then encourage us to explore the viability of the perovskite quantum dot/gold nanoparticle system as a highly efficient LSC. Through dip-coating and optimizing gold nanoparticle concentration, we produce large-scale, uniform, competitively efficient LSCs reaching a maximum efficiency of 2.87% for 10cm x 10cm samples.