[25p-E206-1~9] 12.5 Organic solar cells

[25p-E206-2] Elucidation of the improvement mechanism of open-circuit voltages of ternary PTzBT solar cells using operando ESR spectroscopy

〇Dong Xue¹, Seira Yamaguchi¹, Masahiko Saito², Itaru Osaka², Kazuhiro Marumoto^1,3 (1.Div. Mater. Sci., Univ. Tsukuba, 2.Grad. Sch. Adv. Sci. Engineer., Hiroshima Univ., 3.TREMS, Univ. Tsukuba)

Keywords:Polymer solar cell, Electron spin resonance, Open-circuit voltage enhancement mechanism

Polymer solar cells have been extensively studied because of their features such as low manufacturing cost, large area, and flexibility. In recent years, the power conversion efficiency has been remarkably improved. However, the intrinsic deterioration mechanism has not yet been completely elucidated. Polymer solar cells based on polymeric PTzBT (Fig. 1a) have attracted much attention because of their high conversion efficiency and high durability when ITIC is added to the active layer. Electron Spin Resonance (ESR) spectroscopy is a technique to observe the charge state and molecular orientation inside a device from a microscopic point and to elucidate the deterioration mechanisms of the device. In this study, we applied operando light-induced ESR spectroscopy to polymer solar cells with PTzBT:ITIC:PC61BM and directly observed the charge accumulation state in the devices, and studied the mechanism of open-circuit voltage enhancement and the effect of ITIC addition from a microscopic viewpoint.