Proceedings of Online nanoGe Fall Meeting 20 (OnlineNFM20)
Publication date: 4th October 2020
We investigate the surface and interface of the small organic semiconductor tetraphenyldibenzoperiflanthene (DBP), which can be used as an electron donor in organic photovoltaic devices and N,N′-di-1-naphthalenyl-N,N′-diphenyl [1,1′:4′,1″:4″,1‴-quaterphenyl]-4,4‴-diamine (4P-NPD), which is known as a blue emitter in OLEDs [1] but surprisingly has shown to enhance device performance when implemented as an exciton blocking layer in organic solar cells. We have used XPS at two large scale synchrotron facilities (SOLEIL and BESSY) to explore the core levels, valence bands and work functions of DBP, 4P-NPD and the DBP/4P-NPD interface. Furthermore, we have used NEXAFS at SOLEIL to investigate the LUMO levels of DBP, 4P-NPD and the interface. Electronic modifications at the interface have been deciphered showing absence of interfacial states while evidencing band bending of the 4P-NPD layer. This could explain the improvement observed for OPV efficiency.