Photonics Seminar: Barry P. Rand, Princeton University

Abstract: In this seminar, we will focus on our recent work on two different thin film systems – metal halide perovskites and organic semiconductors.

For organic semiconductors, through proper control of processing, we are able to realize pinhole free films with grains of up to 500 μm in extent. we have found that charge transfer (CT) states incorporating these long-range-ordered films can be highly delocalized, contributing to noticeably lower energy losses. Also, we have discovered that relative energies of CT states with respect to singlet and triplet energy levels are critical when considering devices that exploit multiple exciton processes such as singlet fission and its complement, triplet-triplet annihilation (or triplet fusion). We will discuss these aspects and their implications for more efficient organic solar cell function.