Organic Photodetectors for Applications as Low-cost Sensors (OPALS)

This project will study blend heterojunction photodetectors formed using charge-transporting polymers. The consortium proposes to develop these devices as low-cost organic light sensors for application in digital radiographic panels, as well as image sensors. The partners will use their considerable expertise to create novel polymer semiconductor materials and optimise their performance through device architecture and process development, with a focus on improving the efficiency and colour sensitivity of organic photodetector (OPD) devices. For final applications the development targets will be driven by the demands of the end user, Kodak, who is a partner in this project. This project will build on the foundation of an ongoing EPSRC project that has provided proof of concept for scintillator/polymer photodetector combinations, by providing new materials of industrial quality that are currently lacking, and which are necessary to develop commercial devices. Previous development has also been carried out through an organic photovoltaic (OPV) technology established through collaboration with CDT, and a previous DTI funded project at CDT (PLACES), which focused on applying this OPV technology in solar cell applications. This project will focus on polymer blend OPD devices, pioneered by the University of Cambridge and CDT. Excitons are generated in the active polymer blend layer of the device and are separated into electrons and holes at interfaces between the materials in the active layer and transported to the electrodes. The properties of the polymers, such as light absorption, ionisation potential and mobility are critical for device operation. New materials combinations will be developed by CDT, including polymers with improved electron transport properties, and will be assessed in photodetector devices. The role of the Cavendish Laboratory at the University of Cambridge is to study the physical processes involved in the operation of these devices in order to optimise device operation, to determine the relationship between device performance and blend structure, and to provide feedback on materials design to develop useful, efficient polymer photodetectors.