Organic Semiconductor Interfaces and Their Effects in Organic Solar Cells^†

Abstract

Energy levels and energy level alignment at interfaces play a decisive role in designing efficient and stable organic solar cells (OSCs). In this review two usually used technologies in organic photovoltaic communities for measuring energy levels of organic semiconductors, photoelectron spectroscopy and electrochemical methods, are introduced, and the relationships between the values obtained from the corresponding techniques are compared. The energy level and energy level alignment across the interfaces involved in solution processed organic photovoltaics are described, and the corresponding integer charge transfer model for predicting and explaining energy level alignment are presented. The effects of the interface properties in designing efficient binary and ternary OSCs were discussed. The effects of environmental factors mainly including water vapor, oxygen gas and thermal annealing on energy levels and energy level alignment involved in photoactive layers, and the subsequent effects on the corresponding OSC properties are given.This article is protected by copyright. All rights reserved.

Improved Exciton Diffusion through Modulating Förster Resonance Energy Transfer for Efficient Organic Solar Cells

“…Organic solar cells (OSCs) have garnered increasing attention owing to their favorable attributes, such as flexibility, translucency, cost-effectiveness, and the potential for large-area printing fabrication. [1][2][3][4][5][6][7][8] Recently, the emergence of high-efficiency non-fullerene acceptors (NFA) has led to rapid developments in the power conversion efficiency (PCE) of OSCs. Fluorescence resonance energy transfer (FRET), also known as Förster resonance energy transfer, was initially proposed by Förster in 1948.…”