Improved Self-cooling Exterior Coatings


Visible-emitting fluorescent additive that boosts the self-cooling performance of reflective coatings, for improving temperature control, esthetic appearance, electricity savings and service life of buildings and structures.

  • Improved Self-cooling Exterior Coatings
Research completion
Commercialisation opportunities
Technology licensing agreement
Problem addressed

Polymer coatings with commercially available TiO2 nanoparticles can passively cool down buildings, but the cooling effect is limited by the UV absorption of TiO2. We proposed a fluorescence enhancement strategy to compensate the UV absorption and hence improve the solar reflection and the cooling coating performance, which will promote large-scale applications of the passive daytime radiative cooling technology for combating global warming and energy crisis.

  • Achieving passive daytime radiative cooling requires both high solar reflection and large infrared radiation that minimize heat gain and simultaneously maximize radiative heat dissipation, respectively.
  • Introducing fluorescent pigments into commercially available white coatings competes with TiO2 on UV absorption
  • Re-emit part of the absorbed UV light so as to further reduce the net heat gain from solar irradiation and also make the cooling coatings colorful.
Key impact
  • Low cost and eco-friendly
  • Compatible with commercial coating materials and current construction methods
  • Energy saving
  • No VOC
  • Building envelope
  • Textiles and clothes
  • Electronic and Optoelectronics
  • Warehouse, plant and oil storage tank


  • PWG/PA/1240/5/2022(USA) Patent number: 18/061,624 (USA)
City University of Hong Kong (CityU)

As one of the fastest growing universities in the world over the past decade, City University of Hong Kong (CityU) is recognised as a hub for innovation in research and professional education. CityU identifies solutions to critical global challenges by extending the frontiers of knowledge both within and beyond existing research paradigms.

The University’s highly qualified academics are drawn from all over the world, not only bringing a wealth of research and professional experience to the teaching programmes, but also contributing to the knowledge and technology advancement.