Low work function of the (1000) Ca2N surface

TL;DR

This study uses first-principles calculations to show that the (1000) surface of Ca2N has a significantly lower work function and reactivity than calcium, making it a promising cathode material for polymer LEDs.

Contribution

It introduces Ca2N as a novel cathode material with lower work function and reactivity, based on first-principles calculations.

Findings

Ca2N (1000) surface has 0.5 eV lower work function than calcium.

Ca2N exhibits expectedly smaller reactivity.

Potential application in polymer light emitting diodes.

Abstract

Polymer diodes require cathodes that do not corrode the polymer but do have low work function to minimize the electron injection barrier. First-principles calculations demonstrate that the work function of the (1000) surface of the compound Ca2N is half an eV lower than that of the elemental metal Ca (2.35 vs. 2.87 eV). Moreover its reactivity is expected to be smaller. This makes Ca2N an interesting candidate to replace calcium as cathode material for polymer light emitting diode devices.