The interfacial electronic structure of C60/chloro-aluminum phthalocyanine (ClAlPc)/3,4,9,10-perylenetetracarboxylic- dianhydride (PTCDA) thin films grown on indium tin oxide (ITO) substrates was studied using in situ synchrotron radiation-excited photoelectron spectroscopy and angle-dependent X-ray absorption spectroscopy to understand the influence of the PTCDA interlayer on the performance of small molecule organic photovoltaics (OPVs). The subsequent ClAlPc tilt angle improves the π-π interactions at the interface due to a well-ordered underlying PTCDA interlayer, thus leading to an improved short-circuit current in OPVs based on ClAlPc/C60. Furthermore, the orientation-dependent energy level alignment of the same bilayer heterojunction was analyzed in detail using synchrotron radiation-excited photoelectron spectroscopy. The complete energy level diagrams of C60/ClAlPc with and without the PTCDA interlayer were obtained.
Bibliographical noteFunding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013R1A1A4A01011392). The NSLS is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886.
All Science Journal Classification (ASJC) codes
- Materials Science(all)