Examination Committee

Prof Levent YOBAS, ECE/HKUST (Chairperson)
Prof Zhiyong FAN, ECE/HKUST (Thesis Supervisor)
Prof Baoling HUANG, MAE/HKUST

Abstract

Photovoltaic systems have widely been applied as a major renewable energy resource in our daily life because they can directly convert solar energy into electricity without making pollutions and huge construction cost. The solar panels are installed outdoors and exposed to extreme environmental conditions with dust, UV irradiation, and heat. Therefore, solar cell devices must be packaged with protection layer. But this protection layer may cause a significant reflection of sunlight at the surface. An effective and low-cost nanostructured anti-reflection (AR) technique has long been desired to enhance the performance of high-efficiency photovoltaic devices because it can maximize the light absorption of photovoltaic devices by reducing surface light reflection. However, in the past such kind of nanostructured film have been mostly fabricated with costly processes and small size which limit their practical applications.

In this thesis, large-scale, nano-engineered wafer templates were fabricated to massively produce flexible and anti-reflection films. The optical and electrical improvement was theoretically and experimentally studied by attaching the AR films on polycrystalline Si solar cells. It obviously shows that large-scale AR films have the ability to reduce the surface reflection and enhance the electric output of photovoltaic devices. The improvement is more pronounced at larger light incident angle which is important for the daily operation of photovoltaic devices. Additionally, to enable large scale production, we have demonstrated the nanostructured self-cleaning anti-reflection film fabrication process by low-cost and high-efficiency roll to roll hot embossing method. Though roll to roll hot embossing process, the nanopattern can be transferred to fluorinated ethylene propylene （FEP）film with meter scale. And the film can be mounted on thin film or rigid solar cell easily.