Organic semiconductors make cheap, flexible photovoltaics and LEDs

Schematic of a junction between two organic semiconductors, an anthracene derivative containing free positive ions and a ruthenium, complex containing negative ions. When the two are joined, ions diffuse across the junction creating a difference in energy levels that facilitates rectification, electroluminiscence and photovoltaic response. For experimental purposes the materials were sandwiched between electrodes made of gold and indium tin oxide. The latter is transparent. Credit: Malliaras lab/Cornell University