Prof. Barry P. Rand Order, disorder, and energy loss in organic photovoltaics

Order, disorder, andenergy loss in organic photovoltaics

Barry P. Rand

Princeton University

Departmentof Electrical and Computer Engineering & the Andlinger Center for Energyand the Environment 

Guest talk

Abstract:

We will discuss our recent work to betterunderstand the role of charge transfer (CT) states in organic solar cellfunction. For one, we have been exploring organic semiconductor-based thinfilms that feature crystalline grains of up to 1 mm in extent, termedmicrocrystalline films. We have found that CT states incorporating theselong-range-ordered films can be highly delocalized, contributing to noticeablylower energy losses. In another system, we are studying donor-acceptor pairsthat feature very high optical gaps (>3 eV) but relatively small frontierorbital energy offset (<1 eV). Such interfaces present multiple CT statesthat reveal new insight about photocurrent generation and nonradiativerecombination at donor-acceptor interfaces. Finally, we have developed aframework to discriminate between dynamic and static disorder contributions.Both are shown to contribute, and the relative contribution depends onmaterials choice and temperature.

 
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