Organic solar cells have the advantages of light weight, flexibility, low cost, and low light response, and are currently the hot research topics of solar cell technology. High-efficiency, flex-resistant, and inexpensive flexible organic solar cells are used in flexible wearable and portable electronic devices. There is a strong potential for application in the fields of photovoltaic building integration and military. At present, the research results of most organic solar cells are based on rigid ITO glass substrates. However, if organic solar cells are to be commercialized, Its real advantage is the use of low-cost wet printing and roll-to-roll large-area processes. In organic solar cells, the most commonly used electrode material is indium-doped tin oxide (ITO). However, ITO on plastic substrates There are problems such as poor electrical conductivity and mechanical brittleness, and ITO is usually processed by vacuum sputtering at a high temperature, which makes it expensive and unfavorable for use of large-area printing and roll-to-roll preparation. There have been reports of new electrodes being used. Materials to replace traditional ITO, such as nanosilver wire, graphene, carbon nanotubes, conductive polymers, etc., among which poly(3,4- Ethyldioxythiophene): Poly(styrenesulfonic acid) (PEDOT:PSS) film is relatively low cost, and the film exhibits high optical and electrical properties, excellent thermal stability, good flexibility, etc. Acid doped PEDOT:PSS can greatly increase its conductivity, but most of the current reports use strong acids such as sulfuric acid, nitric acid, etc. Doping, and then high-temperature post-processing, easy to damage the PET and other flexible plastic substrates.
Recently, Ge Ziyi, a researcher at the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, based on the previous research on high-efficiency organic solar cells (Nature Photonics, 2015, 9, 520; Advanced Materials, 2018, 30, 1703005; Macromolecules, 2018, DOI: 10.1021/acs.macromol.8b00683; Journal of Materials Chemistry A, 2018, 6, 464), made new progress in the field of flexible organic solar cells, and innovatively developed the low temperature acid treatment PEDOT:PSS electrode replacement that requires high temperature sputtering and Expensive ITO electrode. The low-temperature methanesulfonic acid treatment improves the conductivity of the PEDOT:PSS film and reduces the roughness of the film, while avoiding the damage caused by the traditional strong acid treatment to the flexible plastic substrate. Further, using the full solution processing technology, the PBDB is adopted. The T- and IT-M non-fullerene active layers were prepared by wet-processed non-ITO single-junction flexible organic solar cells, and the energy conversion efficiency of the battery reached 10.12%. This is a flexible organic process that has been reported so far. The highest efficiency of solar cells. And this kind of all-solution processed flexible organic solar cell is very suitable for roll-to-roll printing and blade coating. The technical requirements of the product preparation process provide an important reference path for the low-cost and flexible preparation of organic solar cells. This work was published in the International Journal on the topic of All Solution-Processed Metal Oxide-Free Flexible Organic Solar Cells with Over 10% Efficiency. On Advanced Materials, Ge Ziyi's team member Fan Xiwei is the co-corresponding author of the paper, and Master student Song Wei is the first author.
The above research has obtained national key R&D plans (2017YFE0106000 and 2016YFB0401000), National Natural Science Foundation of China (51773212, 21574144 and 21674123), Chinese Academy of Sciences Frontier Science Key Research Project (QYZDB-SSW-SYS030), CAS Key International Cooperation Project (174433KYSB20160065), Chinese Academy of Sciences Cross-innovation team, Zhejiang Provincial Outstanding Youth Fund (LR16B040002) and Ningbo Science and Technology Innovation Team (2015B11002, 2016B10005), etc.
Figure: Schematic diagram of a flexible organic solar cell and its photovoltaic characteristics
