Tailoring Charge Transferring Interfaces for High Performance Organic Photovoltaics

Abstract

Interfacial energetics determines the performance of organic photovoltaic cells (OPVs) based on a thin film of organic semiconductor blends. Since the randomly distributed donor and acceptor phases in bulk heterojunction (BHJ) based OPV devices intrinsically bear high probability of unwanted charge carrier recombination near both electrodes, facilitating collection of desired charge carriers with efficient blocking of the misdirected carriers at electrode interfaces are detrimental for the efficient charge collection and consequent photocurrent generation. However, the complexity of the polymer-based blend system and the indistinct interfaces in multilayer structure hindered comprehensive investigation of the charge-collecting interfaces. Herein, this thesis is dedicated to the systematic understanding the device operation physics at charge collecting interfaces and the optimization of OPV device performance by explicit control of the energy level alignment, carrier selectivity and organic/metal interactions.