Nankai University develops high-performance flexible organic solar cells

Data picture: A Chinese solar cell drone was unveiled at China Beijing International Science and Technology Industry Expo. Photo by Zou Xian

The reporter learned from Nankai University on the 5th that the international top academic journal "Nature Electronics" (Nature Electronics) recently published a research paper by the team of Professor Chen Yongsheng of the School of Chemistry of Nankai University, introducing them in the field of flexible transparent electrodes and flexible organic solar cells. Breakthrough progress made.

The team of Chen Yongsheng prepared a silver nanowire flexible transparent electrode with high conductivity, high light transmission and low surface roughness, which was used to construct a flexible organic solar cell, which is equivalent to the performance of devices using commercial indium tin oxide (ITO) glass electrodes , The photoelectric conversion efficiency can reach 16.5%, which has refreshed the highest record of the photoelectric conversion efficiency of flexible organic / polymer solar cells reported in the literature. This achievement makes the efficient and flexible organic solar cells one step closer to industrialization.

Flexible electronic devices, especially optoelectronic devices based on organic materials, are a major trend in the future development of electronic devices and have huge application prospects.

"Among them, obtaining high-performance flexible transparent electrodes is a prerequisite for achieving efficient and flexible organic optoelectronic devices, and is also a core problem in this field. However, how to obtain high conductivity, high light transmission, low surface roughness and simple preparation methods, The green flexible transparent electrode is still a huge challenge. "Chen Yongsheng said.

Due to the lack of the above-mentioned high-performance flexible transparent electrodes, the performance of current flexible organic optoelectronic devices still lags far behind corresponding rigid devices. Flexible transparent electrodes are usually prepared by dry methods (such as evaporation) or solution processing (such as slit printing, nano-imprinting, or electrospinning, etc.). Compared with the dry method preparation, the solution treatment method preparation has the advantages of low cost, large-scale printing preparation, etc., and huge development potential.

Chen Yongsheng's team used polymer electrolytes to prepare silver nanowire flexible transparent electrodes with a "mesh-like" structure. The flexible transparent electrode achieves excellent performance, low surface roughness, excellent mechanical properties and thermal stability, and the preparation method is simple and green.

In order to prove its practicability in organic optoelectronic devices, Chen Yongsheng team prepared a flexible organic solar cell based on the flexible transparent electrode. Research shows that the electrode can be applied to different types of active materials and single junction and stacked photovoltaic devices. Single-junction and stacked flexible organic solar cells achieve photoelectric conversion efficiencies of 13.1% and 16.5%, respectively, and exhibit excellent mechanical properties. The device can still maintain more than 95% of the initial efficiency after continuously bending 1000 times.

"In addition to being applied to organic solar cells, this low-cost, high-performance flexible transparent electrode will also have great application potential in the fields of organic light-emitting diodes, transistors, sensors, etc." Chen Yongsheng said. (Zhang Daozheng Wu Junhui)