[5p-A504-1~17] 12.2 Characterization and Materials Physics

△ [5p-A504-4] Observation of electronic structure at PEDOT:PSS / C₇₀ interface

〇Akira Onishi¹, Kouki Akaike¹, Takumi Kumai¹, Kaname Kanai¹ (1.Tokyo Univ. of Sci.)

Keywords:organic semiconductor, organic solar cell

In this work, we investigated electronic structure at PEDOT:PSS / C₇₀ with photoelectron spectroscopy. Ultraviolet photoelectron spectroscopy on this interface revealed that the HOMO of C₇₀ shifts toward Fermi level and concurrently vacuum level shifts upward with increasing C₇₀ coverage. This implies electron transfer from PEDOT:PSS to C₇₀. X-ray diffraction suggests that molecular order of C₇₀ is not high on PEDOT:PSS. Based on this information, we speculate that the tailing states of the broadened LUMO, due to less structural order, might be occupied to achieve thermodynamic equilibrium throughout the heterostructure. In the presentation, with result of inverse photoemission spectroscopy, we will discuss how electron transfer occurs from high-work function PEDOT:PSS to C₇₀.