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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Organic Electronics and Photovoltaics I

CPP 18.9: Vortrag

Dienstag, 19. März 2024, 12:00–12:15, H 0110

Comparison of electron affinities in organic semiconductors measured by cyclic voltammetry, conventional inverse photoelectron spectroscopy, and low-energy inverse photoelectron spectroscopy — •Mihiro Kubo¹ and Hiroyuki Yoshida^1,2 — ¹Chiba University, Chiba, Japan — ²Chiba University MCRC, Chiba, Japan

The electron affinity (A) of an organic semiconductor is an essential energy parameter representing the electron transport level. Although A in solid can be determined by inverse photoelectron spectroscopy (IPES), A is often estimated from the reduction potential (E_red) measured in solution by cyclic voltammetry. However, because previous IPES data have errors of about 0.3-0.5 eV due to sample damage and low energy resolution, the correlation between E_red and A is uncertain. With the development of low-energy inverse photoelectron spectroscopy (LEIPS)^[1], the precision of A better than 0.1 eV became possible. In this work, we establish a new correlation using LEIPS data A=(1.24±0.07)*eE_red+(5.06±0.15) eV^[2]. In practice, the slope of the correlation is almost similar and A values calculated from this work and previous work differ by less than 0.2 eV over the whole range, although the accuracy of each A should be much higher in LEIPS. Therefore, we further discuss the relationship between the A determined by conventional IPES and LEIPS in terms of energy resolution, sample damage, and vacuum level determination. [1] H. Yoshida, Chem. Phys. Lett., 539-540, 180 (2012); [2] M. Kubo, H. Yoshida, Org. Electron., 108, 106551 (2022).

Keywords: Organic semiconductor; Electron affinity; Reduction potential; Low-energy inverse photoelectron spectroscopy; Cyclic voltammetry