Synthesis and Properties of a Conjugated Acceptor Material for Organic Solar Cells Based on Indacenobis(dithieno[3,2-b:2 ',3 '-d]pyran)

Ke, X (Ke, Xin); Meng, LX (Meng, Ling-xian); Wan, XJ (Wan, Xiang-jian); Zhang, X (Zhang, Xin); Chang, MJ (Chang, Mei-jia); Li, CX (Li, Chen-xi); Chen, YS (Chen, Yong-sheng)^{[ 1 ]}

ACTA POLYMERICA SINICA, 2020, 51(2): 148-157

DOI: 10.11777/j.issn1000-3304.2019.19131

摘要

We designed and synthetized a new non fullerene acceptor with an A-D-A structure, named IDTO2HT-2F, based on indacenobis(dithieno[3,2-b:2',3'-d]pyran) for organic solar cells. The dithieno[3,2-b:2',3'd]pyran will improve the electron-donating capability of the unit and lift the highest occupied molecular orbital (HOMO). Thus, the band gap decreases, making the maximum absorption peak red-shift. Theoretical calculation based on density functional theory (DFT) proved the feasibility of this molecular design. The molecule IDTO2HT-2F has a narrow bang gap of 1.30 eV with the solid absorption edge extended to 956 nm, which is complementary to that of the polymer PM6 film. The broad absorption of the active layer ensures the photovoltaic device to produce high photocurrent. With 0.5% DIO additive and thermal annealing at 120 degrees C for 10 min, the organic solar cell based on the acceptor IDTO2HT-2F and the polymer PM6 exhibits a power conversion efficiency (PCE) of 10.85% with a short circuit current density (J(sc)) of 20.61 mA cm(-2), an open-circuit voltage (V-oc) of 0.86 V and a fill factor (FF) of 0.62. The results indicate that the strategy of introducing pyran into the molecular backbone is an effective way to tune the absorption and energy level of the molecules, which is also a promising method to design new non fullerene acceptors.