Cost-effective high-efficiency 3D nanopillar array solar cells
Environmental protection is everyone’s concern. That’s why experts keep looking for clean and green energy sources that are sustainable and least impactful to the ecosystem.
One of such sources is solar power. Since the 1970s, crystalline silicone (c-Si) solar panels have been in operation. Yet, they incur much initial cost while being rigid and fragile.
The new generation of thin-film solar cells incur much less cost, being less fragile, more flexible, lighter and easier to handle than their c-Si counterparts. On the down side, thin-film solar cells have lower efficiency rate.
Researchers at The Hong Kong University of Science and Technology (HKUST) successfully invented a high-efficiency and cost-effective thin-film photovoltaic technology with revolutionary 3D nanopillar structure that is lightweight and flexible. HKUST is now looking for licensees from around the world who are interested in the patented technology.
Light, flexible and efficient
As the second-generation photovoltaic system, thin-film solar cells also have the advantage of absorbing a broader spectrum of solar radiation than c-Si cells, covering further in the infrared and ultraviolet range.
The intensity and direction of sunshine are not as relevant to thin-film solar cells boasting copper-indium-gallium-selenide (CIGS) in particular. In other words, they convert more sunlight for longer hours each day than c-Si cells no matter how thick the cloud is.
The market share of thin-film solar cells reached 17 per cent in 2009, according to the Frunhofer Institute. Thereafter, the price of conventional c-Si panels plummeted considerably due to global overproduction. The market share of thin-film solar cells also declined to nine per cent in 2013, Frunhofer reported. Despite lower initial cost and flexibility, thin-film solar cells are less efficient than conventional c-Si panels and they must occupy a larger area to produce the same energy.
While the dominant crystalline solar modules show efficiency ratings from 14-20 per cent, thin-film cells are merely converting at 8-13 per cent. In some applications, the low efficiency of thin-film solar cells can offset their price advantage.
In order to improve the performance of thin-film photovoltaic, the research team at HKUST developed a CIGS-based thin-film solar cells featuring pillar-like nano-structure that greatly increases the surface area for light absorption.
The 3D nanostructured film is produced by electrodeposition. To reduce production cost, CIGS nanoparticles are ink-jet printed onto the 3D nanopillar arrays rather than using vapour deposition.
The resultant solar cells demonstrate unique light trapping and scattering properties in lab experiments. To top it off, the team developed a self-cleaning nano-cone antireflection skin over the 3D nano-thin film to protect the cells and to minimise dirt and dust accumulation that may hinder light penetration.
Not only large-scale solar power applications, such as solar farms, building integrated photovoltaics, rural electrification and solar roadway, benefit from this technology, but also small-scale devices and off-grid sources, such as portable electronics and solar-powered vehicles.
HKUST is now looking for licensees from around the world to incorporate the thin-film 3D nanopillar array solar cells in their photovoltaic products. Given its low cost and significantly enhanced efficiency, the technology is deemed to catch on in the market.
Contact information: laura.yu [at] isis.ox.ac.uk (Laura Yu)
• This article is part of the ‘ITF Projects Commercialisation Programme’ hosted by Hong Kong Science and Technology Parks Corporation (HKSTP) in conjunction with Isis Innovation, the technology transfer company of the University of Oxford. The programme aims to expose Hong Kong innovations to international audiences and hence, facilitate commercialisation via the network of Isis. For information on all projects in the programme, please visit
This project is organised by Hong Kong Science & Technology Parks Corporation. Any opinions, findings, conclusions or recommendations expressed in this material/event (or by members of the project team) do not reflect the views of the Government of Hong Kong Special Administrative Region, the Innovation and Technology Commission or the Vetting Committee of the General Support Programme of the Innovation and Technology Fund.