Enhanced carrier injection hotspot effect by direct and simple ITO surface engineering

Abstract

Direct and simple surface engineering of indium tin oxide (ITO) by appropriate Ar plasma treatment was used to induce the carrier injection hotspot effect, similar to reported indirect approaches based on the introduction of additional nanostructures on ITO. Surface characterization analyses and electric field simulations indicate the formation of small-sized and dense injection hotspots on the treated ITO. Efficient electron injection was achieved in both inverted organic light-emitting diodes and corresponding electron-only devices employing the treated ITO as bottom cathode. The present results show that, in addition to the electronic structure, the microscopic morphology at the contacts could also play a critical role in achieving efficient carrier injection in organic electronic/optoelectronic devices.