Optoelectronic measurements of organic and hybrid solar cells

Abstract

Organic and hybrid perovskite solar cells offer a cost-effective and efficient alternative to traditional silicon solar technologies. Also, the tunability of these photoactive materials allows for devices to be crafted for bespoke purposes, such as tandem solar cells or for harvesting energy from indoor lighting. The work in this thesis presents the development, understanding, and application of these materials. First, the development of two new small molecule materials for organic solar cell application is discussed. Their solar cell performance is optimised using several techniques to control the organic semiconductor film morphology and changes to the film are characterised using atomic force microscopy. The stability of these new solar cells is then measured in ambient conditions under constant illumination, which is correlated to the film morphology. Then the electron mobility of two high-performing non-fullerene organic materials using a Time of Flight method is measured. This technique not only allowed for the accurate measurement of the electron mobility of these materials, but also provides insight into the disorder of the organic film and the existence of deep-traps within. Lastly, a hybrid perovskite solar cell is optimised for application in visible light communications for simultaneous energy and data harvesting. In this study the devices are measured under various illumination conditions to gain insight into their loss mechanisms, while also optimising them for this specific purpose.