Realization of Large Open-Circuit Photovoltage in Organic Thin-Film Solar Cells by Controlling Measurement Environment

Abstract

To obtain large open-circuit photovoltage (Voc), we introduced a p-type semiconductor 5,6,11,12-tetraphenylnaphthacene (rubrene), which has a highest occupied molecular orbital (HOMO) level of 5.4 eV. Owing to an adsorption of O2 and H2O into rubrene film, optical absorption peaks were markedly decreased after exposure in air. By controlling the measurement environment to prevent the adsorption of O2 and H2O into rubrene films, we could obtain a high-performance organic thin-film solar cell with a large Voc of 0.91 V.