Trap Engineering for High-Performance Wavelength- Selective Photomultiplication-Type Organic Photodiode

Abstract

The photomultiplication (PM) phenomenon is a sought-after property in photodetector technology as it enables the reliable detection of weak light signals without a pre-amplifier circuit. This simplifies the photo-detection system and enhances its sensitivity. This thesis presents a comprehensive analysis of the fundamental theory of PM-photodetectors, which includes the crystallinity of the PM-matrix, trap-states of the sensitizer, and dielectric constant of the PM-matrix. To this end, poly(3-hexylthiophene-2,5-diyl) nanowires were synthesized with varying crystallinities and introduced into the PM-matrix to understand how the PM-matrix's crystallinity affects the PM-photodetector's sensitivity. In addition, the study investigated the effect of the energy state of the sensitizer by introducing Ag2S NCs with various surfaces as a sensitizer. The goal was to gain insights into how the energy state of the sensitizer influences the PM- photodetector's sensitivity. Finally, double perovskite was incorporated to evaluate the influence of the dielectric constant of PM-matrix on the performance of the PM-photodetector. Taken collectively, this thesis offer a more comprehensive understanding of the factors influencing the sensitivity of PM- photodetectors and can guide the design of more efficient and reliable photo-detection systems.