Opportunities for energy level tuning at inorganic/organic semiconductor interfaces

Abstract

The aim of this Perspective is to provide an overview of approaches that can be employed to tune the energy level alignment at interfaces between inorganic and organic semiconductors for use in electronic and optoelectronic devices. The approaches include tailoring intramolecular dipolar bond distribution, controlling molecular orientation at interfaces, and the insertion of a molecularly thin interlayer that abruptly shifts the electrostatic potential between the two semiconductors and, thus, affords level tuning. With these state of the art methods, the frontier energy levels at an inorganic/organic heterojunction can be varied up to ca. 3 eV, i.e., covering the energy gap of most semiconductors. By combining two or more of these approaches or by employing interfacial molecular switches, it is envisioned that unconventional and dynamically switchable interfacial energy level scenarios can be created, enabling expanded or superior device functionality.