With the support of the Frontier-oriented Key Projects and the Excellent Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 21722404 and 21734008), Chinese scholars have made progress in the research of near-infrared light absorption polymer solar cells. The relevant paper was published in Advanced Materials with the title of “Near-Infrared Electron Acceptors with Fluorinated Regioisomeric Backbone for Highly Efficient Polymer Solar Cells” on November 06, 2018.(30(52):1803769) 

       Polymer solar cells (PSCs) have made continuous breakthroughs in the recent few years, which can be raised from the fast development of novel organic semiconductor molecules and polymers. Organic semiconductor molecules and polymers can regulate their optical, electrical and film properties in a wide range through structural tailoring, thus many multifunctional polymer solar cell devices were rapidly developed including visible-range transmission PSC devices, high near-infrared photon responsiveness and semitransparent PSC devices and full-spectrum absorption tandem PSC devices, which are different from traditional inorganic solar cells. Therefore, the development of new near-infrared light-absorption organic semiconductor materials (band gap Eg < 1.4  eV)  has become a hot spot in the field. 

      Recently, the organic semiconductor laboratory of the polymer science and engineering department of Zhejiang University has developed a family of nonfullerene near-infrared electron acceptors molecules based on non-fused or fused skeletons. Professors Li Changzhi and Chen Hongzheng have designed a family of optimized performance near-infrared electron acceptor molecules for constructing high efficient PSCs with photon response up to 1000 nm. It is found that the tuning of the regioisomeric bridge and fluoro-substituents on a molecular skeleton strongly improves the backbone conjugation and molecular orbital energy level, which eventually impacts the performance of derived PSCs. Moreover, the high efficient tandem PSCs are prepared by further matching with the front cells at the absorption band of 800 nm. This paper is also collaborated with professor Ye Xuanli of South China University of Technology and professor Lu Xinhui of the Chinese University of Hong Kong in optical simulation and film morphology testing. This achievement starts with the molecular skeleton structure design, explores the structure-property relationship between molecular structures, film properties and device performances, and provides a new method and approach for the development of near-infrared electron acceptor molecules and near-infrared photon responsiveness PSCs.