Interfacial Electronic Structure of C60/Chloro-Aluminum Phthalocyanine on a PTCDA Layer for Organic Photovoltaic Devices

초록

The interfacial electronic structure of C-60/chloro-aluminum phthalocyanine (ClAlPc)/3,4,9,10-perylene-tetracarboxylic-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 pi-pi 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/C-60. 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 C-60/ClAlPc with and without the PTCDA interlayer were obtained.

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