Princeton University

School of Engineering & Applied Science

Spectroscopic Studies of Organic and Hybrid Materials for Photovoltaic Applications

Dr. Omer Yaffe, Marie Curie Fellow, Columbia University
Engineering Quadrangle, B205
Tuesday, November 17, 2015 - 3:00pm

Organic and hybrid semiconductors are sought-after as inexpensive, printable materials for photovoltaic applications. From a fundamental stand point, they exhibit strong vibronic coupling (electronic and nuclear vibrational coupling) and excitonic (excited electron-hole pair) behavior resulting from their localized electronic states and "soft" structural characteristics. In this talk, I will present a series of spectroscopic studies that demonstrate the potential advantages of such properties in photovoltaic applications: (i) The conversion of a singlet excited state to two triplet states (i.e. singlet fission) in hexacene crystals, (ii) formation of strongly absorbing, ultrathin, hybrid perovskite crystals and (iii) carrier recombination inhibiting, structural dynamic disorder in lead halide perovskite. These studies highlight how the molecular or, soft nature of the materials determine their electronic properties. They also emphasize why it is important to deepen our understanding of the complex interplay between structural dynamics and electronic properties in organic and hybrid semiconductors.