Research On Novel Small Molecule Photovoltaics Materials Containing Electron-absorbing ? Bridges

In recent years,organic solar cells have attracted scientists'great research enthusiasm because of their low production cost,light weight,and large area of flexible processing.According to reports,the optimal PCE of organic solar cells has exceeded11%,but there is still a big gap from commercial applications.The innovation of photovoltaic materials is one of the key issues in the research of bulk heterojunction organic solar cells.In order to effectively improve the spectrum and energy level of materials and enhance the light-absorbing ability of materials,this paper starts with the construction of small-molecule materials containing electron-absorbing?bridges and actively explores the relationship between the molecular structure of high-efficiency small-molecule materials and the photovoltaic performance of solar cells.In this paper,a novel electron-withdrawing unit?fluoro-substituted thiophene?was introduced as a?-bridge in a small molecule system based on oligothiophene,and a small molecule donor material SMD-1 was constructed.The introduction of fluorine atom effectively controled the energy level of the material,but the optical bandgap was slightly wider.The highest PCE of 3.89%was achieved based on SMD-1/PC₇₁BM.In this paper,fluorothiophene was not only introduced as a?-bridge in the donor material,but also was introduced into the high performance non-fullerene acceptor material as a?-bridge,SMA-1 was designed and synthesized.The highest PCE based on PCE10/SMA-1 was 2.43%.Moreover,an electron-withdrawing unit?ester-substituted thiophene?was also introduced on the?-bridge of non-fullerene acceptor materials,and the small molecule acceptor material SMA-2 was constructed.The highest PCE of 1.66%was achieved based on PCE10/SMA-2.