Investigation on the influence of ZnO nanostructures on ZnO / P3HT based hybrid photodetectors

Abstract

Organic and hybrid organic/inorganic photodetectors are attractive alternatives to conventional inorganic photodetectors due to their potential for low cost and low temperature solution-based processing on exible substrates on a large scale. Further these processes can lead to large scale roll to roll fabrication. Owing to the relatively inferior performance of these organic/hybrid photodetectors, their applications have been limited. Improving the performance of these hybrid photodetectors require a rm understanding of how to optimize both material composition and processing parameters. This dissertation aims to achieve improved performance of hybrid photodetectors by enhancing material property and designing new device architecture. This work primarily focuses towards development of ZnO/P3HT based hybrid photodetectors for visible and UV light detection. In this work, parameters for the ZnO growth and the fabrication of ZnO/P3HT devices were systematically optimized. A bu er layer consisting of hole transport material viz. PEDOT:PSS was inserted in the device for further improvement in the overall performance of the hybrid photodetector through facile hole transport. We have also investigated the e ect of varying alkyl chain length of P3AT on the performance of the hybrid photodetector fabricated for the optimized growth conditions. A highlight of this work is the successful integration of surface plasmon resonance in ZnO/P3HT device for performance enhancement of the hybrid photodetector. This approach demonstrates a novel technique for low-cost UV sensor development. The high recti cation ratio of around 1167 and spectral sensitivity of 10.7 A/W at -2 V under an incident light with a wavelength 325 nm has been demonstrated. Furthermore, the hydrothermal growth of ZnO was optimized for obtaining various ZnO nanostructures with controllable size and morphologies and studied its in uence on the performance of hybrid photodetector.