Professor Wang Tao's Team Makes Important Progress in the Field of Non-fullerene Organic Solar Cells
  Recently, a number of academic papers by Professor Wang Tao from the School of Materials Science and Engineering have been published in international leading journals such as Joule, a subjournal of Cell,Advanced Functional Materials, a journalin the field of materialsfrom Wileygroup,, and Reports on Progress in Physics, a journal published byInstitute of Physics (IOP), introducing the substantial progress the research group in the field of novel non-fullerene organic photovoltaics.
  Solar cells have long been regarded as one of the primary ways to obtain renewable energy. In recent years, non-fullerene electron receptors have received extensive attention and made important progress in the field of organic solar cells because of their strong design in chemical structure and the advantages of easy tune in optical band gap and energy level structure. However, the current fabrication of most high-efficiency organic cell devices is still derived from the synthesis design of novel polymer donor materials or small molecular acceptor materials. There is still little research on the molecular ordering, aggregate structure, and structure-activity relationship of organic cells in the photovoltaic system, which restricts the rapid development of organic photovoltaic cells.


  In response to issues above, Professor Wang Tao’s team and Ding Liming’s team from the National Center for Nanoscience and Technology published a research paper in Joule entitled “Molecular order control of non-fullerene acceptors for high-efficiency polymer solar cells” from the point of view of regulating the aggregate structure and molecular orientation of non-fullerene electron receptors. By employing thermal field induction, the transformation has been successfully realized in the small molecular electron receptor COi8DFIC from edge-on and flat-on lamellar crystalline to face-on H- and J-type stacking. The change of molecular ordering and orientation has not only greatly broaden the absorption range of photovoltaic active layer, but also made the consistent orientation of the acceptor in the active layer, shortened the contact distance of the conjugate plane of the acceptor molecule, thus improving the efficiency of exaction dissociation. Finally, binary-polymer solar cells with short-circuit current density up to 28.3 mA/cm2 and power-conversion efficiency of 13.8% have been successfully fabricated. This work establishes an effective relationship between molecular ordering of photovoltaic materials and device performance, offers a new idea for the further preparation of higher-efficiency non-fullerene organic solar cells.
  Professor Wang Tao’s team also found that thermal field assistance could retard the formation of large-size spherulites of non-fullerene small molecular receptor INPIC-4Fduring film casting, which in turn encourages smaller π-π stacking with smaller size, thus, reducing the size of phase separation in the photovoltaic absorbing layer, and leading to the achievement of a power-conversion efficiency of over 13%. The research was published in Advanced Functional Materials entitled “Retarding the crystallization of a nonfullerene electronacceptor for high-performance polymer solar cells” in collaboration with Professor Tang Weihua from Nanjing University of Science and Technology.
  A review paper entitled“A review of non-fullerene polymer solar cells: From device physics to morphology control”by Professor Wang Tao’s research group is published at the invitation of Reports on Progress in Physics, a subjournal of the IOP. This paper systematically summarizes the latest research progress of novel non-fullerene cell devices from the perspectives of design in molecular structure of photovoltaic materials, micro-nano structure regulation of photovoltaic-absorption layers, physics research of device, and construction of multi-cell device, and makes a prospect on the future development strategy of non-fullerene organic solar cells. The first author of this paper is Dr. Robert Gurney, a postdoctoral in Wang Tao’s team, working in collaboration with Professor David Lidzey from the University of Sheffield of the United Kingdom. 


  The first completed unit of the above three papers is Wuhan University of Technology with Professor Wang Tao as the corresponding author. Professor Wang Tao’s research has been supported by large scientific instruments such as Shanghai Synchrotron Radiation Facility in China and Diamond Light Source in Britain. The publication of the series of high-level research findings above indicates that WUT has made considerable progress in the field of novel non-fullerene organic photovoltaics.