Improvement of the charge imbalance caused by the use of a p-type silicon anode in an organic light-emitting diode

An indium-tin oxide anode was replaced with a p-type silicon anode in a bilayer small-molecule organic light-emitting diode. As results, the current increased largely due to the enhanced hole injection and the higher conductivity of the Si anode; the luminous efficiency decreased significantly due to carrier-induced exciton quenching and the worse charge imbalance. Ultra-thin film of SiO2 grown on the silicon anode improved the luminous efficiency to a certain extent by restraining the hole injection; enhancing electron injection became more desired.