Space Charge Transfer in Hybrid Inorganic/Organic Systems

TL;DR

This paper uses density functional theory to analyze how doping and space-charge layers influence charge transfer and work function changes in hybrid inorganic/organic systems, with implications for device design.

Contribution

It introduces a method to explicitly include doping effects and space-charge layers in DFT calculations of hybrid inorganic/organic interfaces.

Findings

Doping significantly affects adsorption energy and electron transfer.

Space-charge layers are the main driver of work function changes.

Doping effects are general for charge-transfer interfaces in HIOS.

Abstract

We discuss density functional theory calculations of hybrid inorganic/organic systems (HIOS) that explicitly include the global effects of doping (i.e. position of the Fermi level) and the formation of a space-charge layer. For the example of tetrafluoro-tetracyanoquinodimethane (F4TCNQ) on the ZnO(000$\bar{1}$) surface we show that the adsorption energy and electron transfer depend strongly on the ZnO doping. The associated work function changes are large, for which the formation of space-charge layers is the main driving force. The prominent doping effects are expected to be quite general for charge-transfer interfaces in HIOS and important for device design.