Chemistry has made a series of progress in polymer solar cell research

Solar energy is an inexhaustible source of clean (green) energy. In recent years, as countries in the world have attached importance to environmental issues, solar cells that convert solar energy into electrical energy have become a research hotspot in various countries and developed and promoted by the industrial community. the key of. Compared to inorganic solar cells, polymer solar cells have outstanding advantages such as low cost, simple manufacturing process, light weight, and flexibility to be prepared. In addition, a variety of conjugated polymer materials are available, and the designability is high. The modification of the materials can be achieved. Effectively improve the performance of solar cells. Therefore, this type of solar cell has important development and application prospects and has become an important research direction.

With the support of the Ministry of Science and Technology, the National Natural Science Commission and the Chinese Academy of Sciences, researchers from the State Key Laboratory of Polymer Physics and Chemistry of the Institute of Chemistry cooperated with organic solid scientific researchers and recently obtained series on conjugated polymer photovoltaic materials. progress.

In wide band gap polymer solar cell donor materials, wide bandgap materials such as MEH-PPV, P3HT, etc. have been used as the main materials of single layer or laminated photovoltaic devices. Recently, they designed and synthesized a thiazole-based wide-bandgap DA copolymer with an energy conversion efficiency of 5.2%, which is the highest reported value for the photoelectric conversion efficiency of polymers with a bandwidth above 2.0 eV. The results are reported on Macromolecules. (2011, 44, 4035–4037), and became the top ten in the number of downloads of the journal during the month of publication.

The researchers also first introduced the electron-withdrawing group sulfone groups into the PBDTTT copolymer to synthesize the polymer PBDTTT-S. The polymer has a broad absorption and a lower HOMO level. The polymer is donor and the PC70BM is The open-circuit voltage of the polymer solar cell of the receptor reaches 0.76 V, and the energy conversion efficiency reaches 6.22% (Chem. Commun., 2011, 47, 8904-8906); meanwhile, the isomer BDP unit of the BDT unit was constructed. The new polymer photovoltaic material has an open circuit voltage of up to 0.8V and an efficiency of 5.2% (Chem. Commun., 2011, 47, 8850-8852).

Recently, they replaced the alkoxy groups on the BDT units of PBDTTT polymers with thiophene conjugated branches to synthesize a two-dimensional conjugated polymer, PBDTTT-CT (see figure). Compared with PBDTTT-C with alkoxy substituents, the hole mobility of PBDTTT-CT is significantly increased, the absorption spectrum is red-shifted and the HOMO energy level is shifted downward, which is favorable for the improvement of the photovoltaic performance. The solar energy conversion efficiency of the polymer with PBDTTT-CT donor and PC70BM as the acceptor has reached 7.6%, which is one of the highest efficiency of the current polymer-donated photovoltaic materials, which has aroused the attention of domestic and foreign academics and even the industrial community (Angew Chem. Int. Ed., 2011, 50, 9697–9702).

Based on a series of research results on BDT-based high-efficiency conjugated polymer photovoltaic materials, they were also invited to write review articles on Polym. Chem. (Polym. Chem., 2011, 2, 2453-2461).

Molecular Structure of PBDTTT-CT Based on Thiophene-substituted BDT 2D Structural Units and Its Comparison with Alkoxy Substituted Polymer PBDTTT-C