High-performance nonfullerene polymer solar cells with open-circuit voltage over 1 V and energy loss as low as 0.54 eV

Qunping Fan^a,1, Zhuo Xu^a,1, Xia Guo^{a, *}（国霞）, Xiangyi Meng^b, Wanbin Li^a, Wenyan Su^a, Xuemei Ou^a,Wei Ma^{b, *}（马伟）, Maojie Zhang^{a, *}（张茂杰）, Yongfang Li^a,c

^a State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China

^b State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China

^c CAS Research/Education Center for Excellence in Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China

¹ Q.P. Fan and Z. Xu contributed equally to this work.

Nano Energy 40 (2017) 20--26

In this work, we developed high efficiency nonfullerene PSCs based on a wide bandgap polymer donor PBPD-Th with a structure of meta-alkoxyphenyl benzodithiophene-alt-thienyl benzodithiophene-4,8-dione and a low bandgap small molecule acceptor ITIC. The PBPD-Th shows a strong absorption in the short wavelength of 300–650 nm with a bandgap of 1.91 eV, which is complementary with that of ITIC (1.55 eV). Moreover, PBPD-Th possesses a deep HOMO level of −5.42 eV, which is beneficial to obtain high open-circuit voltage (V_oc) in PSCs. As a result, the optimal PSCs based on PBPD-Th: ITIC showed a power conversion efficiency (PCE) of 10.8% with a V_oc of up to 1.01 V, a high short-circuit current density (J_sc) of 18.3 mA cm⁻² and a fill factor (FF) of 59%, under the illumination of AM 1.5 G, 100 mW cm⁻². Notably, the energy loss (E_loss) of the optimal PSCs is 0.54 eV, which is smaller than the empirically low threshold of 0.6 eV. The PCE of 10.8% is one of the highest values reported in the literatures for the PSCs with V_oc over 1.0 V.

链接：http://www.sciencedirect.com/science/article/pii/S2211285517304603