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Public Seminar of RPg Student:
Enhance photosynthesis by asymmetrical structures designed spectral-converting films

Speaker Ms. Qiuyi LYU
Affiliation The University of Hong Kong
Date June 11, 2024 (Tuesday)
Time 9:30 a.m.
Venue Room 522, 5/F, Chong Yuet Ming Physics Building, The University of Hong Kong


Photosynthesis plays a crucial role in crop yield and carbon budget as it directly determines the conversion of solar energy into plant biomass and the fixation of CO2. However, photosynthesis is inefficient and 51% of the energy loss is due to being outside the photosynthetically active spectrum. Existing spectral-converting greenhouse envelopes suffer from low light extraction efficiency and low external quantum efficiency due to the total internal reflection. Here, we design the asymmetrical spectral conversion films with micro photonic structures. Through the optimization of these micro-structures using Monte-Carlo simulations, the light extraction efficiency and external quantum efficiency were increased to 89% and 47%, respectively. Subsequent experiments showed that the fabricated film had forward external quantum efficiency of 40%, representing a 22% improvement compared to a planar film without micro photonic structures, approximately doubling the original data. Furthermore, a more fined spectrum adjustment was proposed by utilizing different luminescent materials, which is based on characteristics of the impact of red/far-red light ratio on plant growth. The designed asymmetrical structures on spectral-converting film are expected to enhance photosynthesis and have the potential to increase crop yield as well as carbon fixation.