Chemistry Weekly Seminar - Rick Pettipas, PhD Candidate

Title

Perylene Diimide as an Electron Accepting Material in Solar Cells and an Electron Transporting Material in X-ray Detectors

Abstract

Perylene diimide has proven its utility as a building block for the development of electron accepting and transport materials. For photovoltaic application, unmodified perylene diimide over-crystallizes when blended with other materials, which leads to poor charge transport and exciton recombination. Bay-substitution of these is an effective strategy to introduce steric bulk but makes it difficult to modify the structure further. When pairing this acceptor, most electron donors do not require additional modification, but donors with low lying E_LUMO have insufficient offset to drive charge separation. Given the competition for the bay region, my research has focused on the development of imide linked perylene diimide dimers to prevent over-crystallization whilst using the bay region to further modify E_LUMO.

In the second portion of this talk, I will discuss my recent work on perovskite X-ray detectors utilizing perylene diimide as an electron transport material. Perovskite has proven itself as a material for photovoltaics, but more recently has emerged as a promising material for X-ray detection and imaging. The recent interest has been spurred by the high stopping power and solution processability of lead halide perovskite which offers a competitive edge over commercial amorphous selenium detectors. Recent work has demonstrated these materials could improve upon signal to noise ratio and reduce fabrication costs for X-ray imaging and sensing applications. In this talk, I will discuss our recent work on scalable fabrication of perovskite X-ray detectors featuring low dark currents.