The purpose of this project is to use Kelvin probe and ambient photoemission measurements to measure energy levels of organic and hybrid semiconductors, and relate the results to the performance of these materials in photodiodes and sensing applications. The project aims to identify ways in which the above techniques can give new insight into organic and hybrid semiconductor materials and devices. In particular it aims to develop a measurement technique to determine the LUMO of an organic semiconductor which is important both for explosive sensing and for selection of appropriate acceptors for photodiodes. In addition scanning measurements will lead to imaging of the electronic properties of materials. It will progress the state of the art by providing new information and optoelectronic techniques to enable rational design of materials and devices. The resulting new knowledge is expected to be in the domains of materials science, device physics and instrumentation.