The Institute of chemistry of the Chinese Academy of Sciences has made a series of progress in the field of all small molecular non fullerene organic solar cells

Organic solar cells are composed of p-type organic semiconductors (p-os) and n-type organic semiconductors (n-os ）In recent years, it has become a research hotspot in the field of new energy research because of its simple structure, light weight, low cost and the advantages of preparation of flexible and translucent devices by solution processing P-os donor photovoltaic materials include conjugated polymers and organic small molecules Compared with polymers, small molecular materials have the advantages of definite molecular structure, no difference of synthetic batches, easy purification, etc., so organic small molecular donor photovoltaic materials have also attracted people's attention All small molecule non fullerene organic solar cells use p-os small molecule donor and n-os small molecule acceptor, and have the advantages of small molecule donor materials and non fullerene small molecule acceptor materials, which has recently become an important research direction in the field of organic solar cells With the support of the leading project of the Chinese Academy of Sciences, the researchers of the research group of the Key Laboratory of the Institute of organic solids of the Chinese Academy of Sciences recently made a series of research progress in the research of p-os small molecule donor materials and all small molecule non fullerene organic solar cells, making the energy conversion efficiency of all small molecule organic solar cells break through 10% A - π - D - π - A (where d represents donor structural unit and a represents receptor structural unit) is the linear molecular structure of p-os small molecular donor materials Based on the J-series high-efficiency polymer donor photovoltaic materials developed by them for non fullerene polymer solar cells, they first synthesized p-os small molecules H11 and H12 based on benzodithiophene (BDT) as donor unit, fluorotriazole (fbta) as receptor unit and cyanoacetate as terminal receptor unit The open circuit voltage (VOC) and energy conversion efficiency (hereinafter referred to as efficiency) of all small molecular organic solar cells with H11 as donor and n-os small molecule idic as acceptor reached 0.977 V and 9.73% (j.am.chem.soc 2017, 139, 5085-5094) N-os small molecule receptor materials have the characteristics of anisotropic conjugated skeleton, so optimizing the molecular structure of p-os to adjust the morphology of all small molecule active layer to form a good donor receptor nano scale phase separation interpenetrating network structure is an important means to improve the photovoltaic performance of all small molecule organic solar cells Two p-os molecules SM1 and SM2 were synthesized by introducing the oligothiophene structure into the p-os molecular structure with BDT as the central donor unit Based on SM1: idic, the efficiency of all small molecular organic solar cells has reached 10.11% (CHEM mater 2017, 29, 7543 – 7553), which is the first time that the efficiency of all small molecular non fullerene organic solar cells has exceeded 10% In the two-dimensional conjugated polymer based on thiophene instead of BDT, silane side chain can effectively reduce the HOMO energy level of the polymer, enhance the absorption and increase the hole mobility In order to further improve the photovoltaic performance of all small molecular organic solar cells, they recently introduced the two-dimensional BDT unit with silylthiophene as side chain into the p-os small molecule donor materials, and synthesized two new p-os small molecule donor photovoltaic materials H21 and H22, and studied the influence of different end receptor units on the physical and chemical properties and photovoltaic performance of the materials The photoelectric conversion efficiency of all small molecular organic solar cells based on H22: idic is further increased to 10.29% This result was recently published in adv mater (DOI: 10.1002 / ADMA 201706361).