CAREER: Origins and Applications of Optical Anisotropies in Organic Photonics

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

Non-technical Description: Semiconductor materials are the foundation of modern photonics, or light-manipulating technologies (e.g. lasers, solar cells). Conventional semiconductors such as silicon form crystals, often with isotropic optical properties. Organic materials, such as plastics, provide an alternative low-cost, light-weight, and flexible semiconductor system. These materials comprise highly asymmetric molecules that assemble into complex structures. As a result, they often exhibit highly anisotropic optical properties. The research component of this CAREER award is to study the origins and applications of these optical anisotropies. Novel measurement methods of optical anisotropies help to provide fundamental insight into the complex optical properties of organic materials. In turn, this project exploits optical anisotropies to enhance the performance of organic photonic devices. These scientific investigations are complemented by a variety of integrated education and outreach objectives. A new outreach initiative, The Art of Science, explores intersections between art and science. Students turn the products of their research into works of art for exhibition in public venues, including the Santa Barbara Museum of Art. This initiative encourages science literacy and appreciation through aesthetics, and promotes science as a creative endeavor. Technical Description: Organic materials used in photonic devices often self-assemble into highly oriented morphologies, leading to huge optical anisotropies. The objective of this CAREER project is to elucidate the origins and applications of these anisotropies. The approach is to (1) develop new optical methods for characterizing anisotropies based on resolving the photon momentum vector; (2) identify distinct temporal and spectral signatures of intra- and inter-molecular luminescence; (3) quantify absorption anisotropies that challenge currently prevailing models of organic optical constants; and (4) integrate oriented organics with photovoltaic light-trapping architectures that exploit anisotropies to enhance thin-film absorption. Fundamental materials studies provide new understanding of inter-molecular excitations - critical, but poorly understood intermediaries in organic light emitting diodes and photovoltaics. Investigations of photonic architectures delineate new approaches for enhancing oriented light-matter interactions through electromagnetics coupling.