From Surface Plasmon Resonance to Hot Electron Emission: Pioneering Next-Generation of Enhanced Photodetection

Abstract

This thesis delves into the intricacies of nonlinear optical rectification, focusing on DC photovoltage generation and emphasizing the pivotal role of gold nanostructures in elucidating optoelectronic behaviours. Within this purview, a novel exploration emerges regarding nonlinear processes vital to DC photovoltage generation, especially in the milieu of OR detection experiments using a capacitor-based configuration. Gold nanostructures, specifically nanoparticles and nanorods, stand paramount in this study. By expertly modulating the aspect ratios of gold nanorods, the research elucidates the subtle influences on surface plasmon resonance, thereby highlighting these structures' profound capabilities in energy conversion, photodetection, and sensing. Energy conversion initially took precedence, and the research trajectory evolved upon discerning the heightened potential of these structures in bolstering photodetector and sensor performances. A salient facet of this investigation is the comparative analysis between gold nanorods and nanoparticles. Ingeniously engineered nanoparticles were found to mimic many optoelectronic behaviours intrinsic to nanorods. Such revelations paved the way for designing a prototype capacitor device exemplifying Au nanoparticles to interrogate its nonlinear attributes, especially in resonance with wavelengths proximal to the Local Surface Plasmon Resonance. This device serves as an exemplary nexus between theoretical postulations and pragmatic applications. Subsequent research ventured into thiol-functionalized gold nanoparticles, revealing a marked enhancement in OR post-functionalization with thiols. Intriguingly, the magnitude of this influence manifested variations based on the specific thiol employed. These thiol-enveloped entities showcased remarkable adaptability to environmental perturbations, underlining their potential in enduring sensor applications. This thesis offers a profound, holistic examination of gold nanostructures, emphasizing thiol-functionalized iterations. The findings proffered augment the scholarly discourse on the topic, concurrently furnishing a schematic for forthcoming pursuits in this enthralling domain of nanotechnology.