Nat. Commun.: researcher Li Yongfang, Institute of chemistry, Chinese Academy of Sciences has made important research progress in low-cost and efficient polymer donor photovoltaic materials

Polymer solar cells are composed of p-type conjugated polymer donor and a blend active layer of fullerene derivatives or non fullerene n-type organic semiconductor receptor sandwiched between transparent conductive electrode and metal electrode They have outstanding advantages of solution processing, light weight, and preparation of flexible and semi transparent devices In recent years, they have become a research hotspot in the field of global energy The commercial application of polymer solar cells needs to achieve high efficiency, high stability and low cost of devices, which mainly depends on the development of photovoltaic materials Since Alan J Heeger and others put forward the concept of bulk heterojunction in 1995, the research on photovoltaic materials and devices of polymer solar cells has obtained continuous development In the early stage of the research, the efficiency of the device is very low, and the main focus of the research is to improve the efficiency Through the design and synthesis of narrow-band system, wide absorption and polymer donor photovoltaic materials with lower Homo level, and fullerene derivative receptor photovoltaic materials with higher LUMO level, the short-circuit current, open circuit voltage and energy conversion efficiency of the device can be improved In recent years, with the development of narrowband gap non fullerene n-type organic semiconductor receptor photovoltaic materials and broadband gap polymer donor photovoltaic materials that absorb complementary materials, the energy conversion efficiency of polymer solar cells has been improved rapidly Recently, the efficiency of small area devices in the laboratory has exceeded 12-13%, reaching the threshold of practical application Therefore, improving the stability and reducing the cost become the key to realize the practical application of polymer solar cells However, most of the reported high-efficiency photovoltaic materials are complex in structure and difficult in synthesis, which is difficult to meet the needs of commercial applications The development of low-cost and efficient photovoltaic materials will be a great challenge for the commercial application of polymer solar cells (a) molecular structure of donor ptq10 and acceptor idic; (b) structure diagram of battery devices; (c) synthesis route of ptq10; (d) and (E) comparative analysis diagram of synthesis steps, yield and efficiency of polymer solar cell donor materials (source: Institute of chemistry, Chinese Academy of Sciences) supported by NSFC and pilot project of Chinese Academy of Sciences, Li Yongfang, a team of researchers in the Key Laboratory of the Institute of mechanical and solid Sciences, Chinese Academy of Sciences, recently designed and synthesized a low-cost and efficient polymer donor material ptq10 Ptq10 is a kind of D-A copolymer with simple structure, in which thiophene ring is the donor unit and quinoxaline is the receptor unit The purpose of introducing alkoxy side chain to quinoxaline is to improve the solubility and light absorption of the polymer, to reduce the HOMO energy level of the polymer and to increase the hole mobility The molecule can be synthesized in two steps by cheap raw materials and achieve a total yield of nearly 90%, which greatly reduces the cost of the material What's more, the highest energy conversion efficiency of polymer solar cell using ptq10 as donor and n-type organic semiconductor idic with relatively simple structure as acceptor is 12.70%, and the efficiency of reverse structure device is 12.13% (the efficiency confirmed by China Academy of metrology is 12%) Moreover, the device efficiency can be more than 10% in the range of 100nm to 300nm, which is very conducive to the large area preparation of the device Compared with other high-efficiency polymer donor photovoltaic materials with efficiency over 10% reported in the literature, ptq10 has outstanding advantages in terms of synthesis steps, yield and efficiency Considering the advantages of low cost, high efficiency and insensitive thickness, ptq10 is very promising to be a polymer donor material in the commercial application of polymer solar cells Thesis link: https:// brief introduction of researcher Li Yongfang http://liyf.iccas.ac.cn/42