Co-organized by the Mechanical, Marine, Naval Architecture & Chemical (MMNC) Division, Gas and Energy (EG) Division, Materials Division of The Hong Kong Institution of Engineers (HKIE), The Institution of Engineering and Technology (IET – Hong Kong Branch) and the Mechanical Engineering (ME) Department of The Hong Kong Polytechnic University (PolyU), a technical seminar with the theme “Breakthrough on Nanofiber Technologies to Air Purification and Solar Cells” was delivered by Ir Prof. Wallace Leung, Chair Professor of Innovative Products and Technologies of ME Department of PolyU, on 25th April 2018. Over 100 HKIE and IET members participated in the seminar.

Nanofiber is non-woven, randomly oriented very fine fiber with a fiber diameter less than 1000 nanometer. Prof. Leung started by introducing the physical features, materials and production methods of nanofiber. Then, he divided his presentation into two main topics: Nanofiber in Energy and Nanofiber in Environment.

For the first topic, he talked about application of nanofiber on solar cells. He introduced an environmental-friendly PV technology, the dye sensitized solar cell (DSSC), which uses an organic dye to effectively harvest solar energy and convert photons to electrical charges efficiently. Three technologies on nanofiber-based DSSC along improvements in light trapping, light harvesting and charge transport have been discussed. The adoption of bilayer TiO2 nanofibers, CuPC co-sensitization and carbon nanotube in TiO2 nanofibers brings significant efficiency improvement of DSSC.

Nanofiber technology also gives remarkable contribution in air quality improvement. Filtration using nanofibers arranged in novel configurations can remove particulate pollutants and air borne viruses as small as 10-100 nm with high capture efficiency, high aerosol holding capacity, low-pressure drop and stable performance. These nanofiber technologies present a wide range of applications, from facemask, respirators, cabin filter, HVAC, engine, turbine, hospital wards to industrial uses. Besides, novel nanofiber photocatalysts, which are made of composite semiconductor such as TiO2-ZnO, can purify gases effectively by breaking down harmful substance to carbon dioxide and water vapor, after harvesting both UV and visible light.

The seminar came to a successful end with an interactive Q&A session and last but not least, souvenirs were presented to Ir Prof. Leung by the HKIE and IET representatives, Miss Winky Lui and Mr. Victor Chan, to thank Ir Prof. Leung for his informative and inspiring sharing.