A high work function anode interfacial layer via mild temperature thermal decomposition of a C60F36 thin film on ITO

Abstract

A high work function anode interfacial layer has been developed via a mild temperature thermal decomposition of fluorinated fullerene (C60F 36) on ITO at 120 °C. As revealed by in situ ultraviolet photoelectron spectroscopy (UPS) measurements, after the interfacial modification, the ITO electrode work function can be as high as ∼5.62 eV. It also possesses very good air stability even after the exposure to air for more than one day. The thermal annealing induced carbon-fluorine bond breaking was confirmed by in situ X-ray photoelectron spectroscopy (XPS) measurements. The residual F atoms are chemically bonded onto the ITO surface. Taking advantage of such a high work function anode interfacial layer on ITO, enhanced performance of a chloroaluminium phthalocyanine (ClAlPc)/fullerene (C60) planar heterojunction based organic solar cell was observed. The performance enhancement is attributed to the higher anode WF together with the optimal nanoscale morphology, and hence better hole collection efficiency. This journal is © The Royal Society of Chemistry 2013.