Organic/inorganic soft matter-based green-energy optoelectronics

In the growing area of solar cell research, the soft matter solar cell with polymer and organic materials as the active layer is a promising type of thin-film solar cell due to its properties of being mechanically flexible, light-weight, easily fabricated and low cost. This joint project focuses on improving the solar cell performance by refining its key components, including the polymer donors and organic acceptors, carrier transport layer, and flexible electrodes.

In terms of the active layer materials, novel and easily dissoluble polymer donors and organic acceptors are being studied. The project focuses on synthesising polymer donors, fullerene derivatives and non-fullerene acceptor materials with strong light absorption and good carrier generation and conduction. Modifications would be introduced to tune their energy levels and to enhance electron mobility for better solar cell performance.

For the carrier transport layer, metal oxides with good and stable electrical properties would be useful to extract photogenerated carriers from the active layer to the electrodes. As such, the focus is to develop low-temperature solution-based metal oxides for the inorganic metal oxide-based carrier transport layer. Work is in progress to introduce new solution-based approaches to produce metal oxides with good carrier transport properties, through which different metal oxides could also be synthesised using the same methods.

Regarding the electrode design, it should be mechanically flexible and have good optical transmission and high conductivity so a new class of flexible nanostructure electrode is proposed. The project includes the design and development of microscopically random and macroscopically periodic metal nanostructures as flexible electrodes for the solar cells and other optoelectronic devices.

The novel materials and nanostructures would not only be cheap and green, but also mechanically flexible and adaptable on various substrates. The combination of material synthesis with device design, fabrication and characterisation would yield significant advances in solar cell performance.

Dr Choy has been working on nanostructural optoelectronics and is currently an Associate Professor at the Department of Electrical and Electronic Engineering at HKU. Professor Hou has been working on polymer material synthesis and is currently a Professor at the State Key Laboratory of Polymer Physics and Chemistry at the CAS Institute of Chemistry. Their joint project hopes to study solar cell components, enhance the current understanding in order to improve solar cell performance and contribute to the evolution of low-cost and high-performance soft matter solar cells for practical photovoltaics in the next generation of energy industries. In addition to promoting the emerging technologies of photovoltaics, they also hope to train research professionals with multidisciplinary knowledge in the field of optoelectronics.