[12a-S221-1~12] 12.5 Organic solar cells

[12a-S221-3] Light-induced ESR spectroscopy observation of long-lived charge states in PTzNTz polymer solar cells and elucidation of performance deterioration mechanism

〇Dong Xue¹, Shinpei Kamiya¹, Masahiko Saito², Itaru Osaka², Kazuhiro Marumoto^1,3 (1.Univ. Tsukuba, 2.Hiroshima Univ., 3.TREMS, Univ. Tsukuba)

Keywords:electron spin resonance, organic solar cells, degradation mechanism

Polymer solar cells have been extensively studied because of its low-cost, large-area production and flexible characteristics. Recently, the power conversion efficiency (PCE) of polymer solar cells have been greatly improved. However, the internal degradation mechanism is still unknown. Inverted-type polymer solar cells using PTzNTz have attracted much attention because of their high PCEs and stability. In this study, we report electron spin resonance (ESR) spectroscopy of highly stable polymer solar cells using PTzNTz to investigate the degradation mechanism of the device performances from a microscopic viewpoint. We observed the correlation between the increase in the number of spins (N_spin) and the decrease in the device performance. We also performed density functional theory calculation to analyze the charge-accumulation states in PTzNTz polymer solar cells.