Multifunctional Bilayer Template for Near-Infrared-Sensitive Organic Solar Cells

作者：Kim Hyungchae; Park Han Gyeol; Maeng Min Jae; Kang Yu Ri; Park Kyung Ryoul; Choi Junho; Park Yongsup; Kim Young Dong; Kim Changsoon

来源：ACS Applied Materials & Interfaces, 2018, 10(19): 16681-16689.

DOI：10.1021/acsami.8b03468

• organic solar cell
• charge-transfer exciton
• CT exciton dissociation
• molecular orientation
• CT-state energetics
• entropy
• disorder

For organic solar cells (OSCs) based on nonplanar phthalocyanines, it has previously been reported that a thin film composed of triclinic crystals with face-on (or flat-lying)-oriented molecules, typically obtained with a CuI template layer, is desired for optical absorption in the near infrared (NIR) spectral region. However, this work demonstrates that for a PbPc-C-60 donor acceptor pair, less face-on orientation with a broader orientation distribution obtained with a new template layer consisting of a ZnPc/CuI bilayer is more desirable in terms of solar cell efficiency than the face-on orientation. A NIR-sensitive PbPc-C-60 OSC employing this bilayer-templated PbPc film is found to increase the internal quantum efficiency (IQE) by 36% on average in the NIR spectral region compared to a device using a CuI-templated PbPc film. Analyses of the change in IQE using the exciton diffusion model and the entropy- and disorder-driven charge-separation model suggest that the improved IQE is attributed to the facilitated dissociation of charge-transfer excitons as well as the reduction in exciton quenching near the indium tin oxide surface.

• 出版日期2018-5-16