Details

Autor(en) / Beteiligte

• Chang, Yuan
• Lau, Tsz-Ki
• Chow, Philip C. Y
• Wu, Ningning
• Su, Dan
• Zhang, Weichao
• Meng, Huifeng
• Ma, Chao
• Liu, Tao
• Li, Kun
• Zou, Xinhui
• Wong, Kam Sing
• Lu, Xinhui
• Yan, He
• Zhan, Chuanlang

Titel

A 16.4% efficiency organic photovoltaic cell enabled using two donor polymers with their side-chains oriented differently by a ternary strategy

Ist Teil von

• Journal of materials chemistry. A, Materials for energy and sustainability, 2020-02, Vol.8 (7), p.3676-3685

Ort / Verlag

Cambridge: Royal Society of Chemistry

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Effective ternary material systems are usually achieved using a donor/acceptor guest that is structurally similar to the donor/acceptor host to maintain the film-morphology of the host binary blend. In this study, we report an unprecedented ternary material system, PBDB-TF:PBDB-T-SF:Y6, in which PBDB-T-SF is selected as the donor polymer guest of the PBDB-TF:Y6 binary blend. The absorption spectra of both polymers are almost overlapped and their energy levels are similar. However, the side-chains between the host (PBDB-TF) and the guest (PBDB-T-SF) are oriented differently, which modulates the morphology of the polymer phases from nanoscale (10-20 nm) fine fibrils in the host binary blend to an interpenetrating mesoscale polymer-crowd (>100 nm) with reduced phase crystallinity in the ternary blend. As a result, the electrical properties of the active layer are greatly improved: the hole mobility increases more than the electron mobility, resulting in balanced hole and electron mobilities; the monomolecular and bimolecular recombinations are both reduced; the charge carrier extraction is faster and the trap-assisted recombination is reduced, resulting in a longer recombination lifetime of charge carriers (0.19 μs vs. 0.15/0.11 μs). All of these contribute to the concurrently increased device fill-factor and short-circuit current-density, and finally improved efficiency (16.4%). Solid-state 19 F magic angle spinning nuclear magnetic microscopy is conducted to probe interaction between the host and guest donor polymers. This study demonstrates that mesoscale morphology such as the polymer-crowd induced by differently oriented side chains of the host-guest polymers can be a morphological feature of active layer toward high-efficiency organic photovoltaic cells. A ternary material system featuring two donor polymers with identical absorption spectra and differently-oriented side-chains was used in an organic photovoltaic (OPV) cell. It is the first ternary blended OPV cell with two donor polymers with >16% efficiency.