More efficient solar cells with quantum dots

Dr Baohua Jia

Swinburne University of Technology, Melbourne, Australia

The global race to develop high efficiency, low cost solar energy is fierce. And Baohua Jia and her colleagues are front runners.

Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)

Conventional solar cells are efficient, but thick and expensive. Baohua and her colleagues imagine a future when solar cells are so thin and cheap that city skyscrapers will be powered by a coating on their glass. But at present such thin-film solar cells are not efficient enough for general use.

Using her knowledge of nanotechnology and optics, Baohua and her colleagues have already created thin-film solar cells that are more than 20 per cent more efficient than those of her competitors. They have already lodged two patents.

But Baohua thinks she can do better. And that will be the focus of the work assisted by her $25,000 L’Oréal Australia & New Zealand For Women in Science Fellowship.

Thin-film cells capture visible light in sunlight, but miss high energy ultraviolet light. Baohua believes that she can use a layer of minute semiconducting particles known as quantum dots to convert ultraviolet light to visible light that the solar cell can handle. So, working closely with Suntech Power, the world’s largest producer of silicon solar modules, she is developing thin-film cells embedded with quantum dots.

“Science is beautiful, that’s why I love it. It tells you how the world works and the rules behind it,” says Baohua.

Growing up near Beijing, Baohua was fascinated by optics, and that led her to a degree in physics, a masters in optical communications and an interest in nanotechnology.

A family member who had spent time in the US encouraged her to travel. And that led in 2002 to the opportunity to do a PhD with Professor Min Gu’s microphotonics research team at Swinburne University in Melbourne. Baohua quickly realised that she could put her passion for, and knowledge of, optics and nanotechnology to practical use, chasing one of the most important technology goals of our time—cheap, clean energy through solar power.

Despite a global investment of billions of dollars in solar energy, it’s still more expensive than the fossil fuel alternatives. The dominant solar cell technology on the market uses silicon wafer cells which, after years of development, now typically capture about 20 per cent of the energy in the sunlight shining on them. But the panels are expensive.

Thin-film silicon cells are much cheaper and use just one hundredth of the silicon required for wafer cells. In theory, they could cover conventional glass and enable skyscrapers to be powered entirely by sunlight.

“But thin-film cells are low efficiency—just 6.5 per cent. Around the world researchers are improving their efficiency but too slowly to make them a practical alternative for industry,” says Baohua.

“Thin-film solar cells face two key challenges,” she says. “The thin film can’t trap enough light, and it can’t absorb the sun’s strong ultraviolet light.” Baohua and her colleagues have already solved the first of those problems and, with the help of the L’Oréal Australia For Women in Science Fellowship and quantum dots, she is now tackling the second challenge.

Her team was using small particles of gold and silver to spread the sunlight within the solar cells. They realised that by making these nanoparticles lumpy they could dramatically increase the scattering of the light, and the efficiency of the solar cells.

The discovery, published in February 2012, boosted the efficiency of thin cells to more than eight per cent. Using quantum dots, her target is a further 40 per cent increase, which would bring the overall efficiency of thin-film solar cells to more than 10 per cent.

That should be good enough to make thin-cell solar cells a commercial proposition. And Baohua’s work involves conventional ‘wet chemistry’ techniques, which should make the transition to commercialisation even smoother.

She is a key member of the Victoria-Suntech Advanced Solar Facility, a collaborative venture between Swinburne University of Technology and Suntech Power Holdings Co Ltd supported by the Victorian Government.

“Every day I’m excited by the idea that my work in nanotechnology can actually do something valuable and meaningful for people’s lives,” Baohua says.

Qualifications

2007 – PhD (Optics), Swinburne University of Technology

2003 – Masters of Science (Optical communications), Nankai University, P.R. China

2000 – Bachelor of Science (Applied Optics) and Bachelor of Economics (Management), Nankai University, P.R. China

Career highlights, awards, fellowships, grants

2010-2015 – Senior Research Fellow, Centre for Micro-Photonics, Swinburne University of Technology

2012-2015 – ARC Discovery Early Career Researcher Award, “Refractive index manipulation in photonic bandgap materials for highly efficient far-field three-dimensional nonlinear nanofocusing”, awarded to Jia B.

2011 – Vice-Chancellor’s Industry Engagement Award, Swinburne University of Technology

2010 – Victoria Fellowship, Victorian State Government

2010 – International Science Linkages – Science Academies Program travel grant for scientific visits to Europe, Australian Academy of Science.

2010 – French Fellowship, Australian French Association for Science and Technology

2011 – ARC LIEF (Linkage Infrastructure, Equipment and Facilities) grant, “Three-dimensional super-resolution nanophotonic fabrication facility”, awarded to Gu M., Gan X., McPhedran R.C., Zhang C., Alameh K., Lewis R.A., Peng, G-D., Catchpole K.R., Juodkazis S., Day D., Jia B., Pan A.V., Horvat J., Canagasabey A., Rode, A.V, de Sterke C.M., Vasilie M.

2009-2011 – ARC Discovery Grant/ARC Postdoctoral Fellow “Functional micro-multiplexers based on nonlinear three-dimensional photonic crystal Superprism”, awarded to Jia, B., Wang X.

2009-2010 – Research Fellow, ARC Postdoctoral Fellow, Project Manager, Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS)—an ARC Centre of Excellence

2009 & 2010 – Travel grant for Australian-China Young Scientist Exchange scheme, Australian Academy of Technological Sciences and Engineering

2009 – Vice-Chancellor’s Research Award (Early Career) for research excellence, Swinburne University of Technology

2008 – Faculty of Engineering and Industrial initiative grant award, Swinburne University of Technology

2006-2009 – Postdoctoral Fellow, Project Manager, Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS)—an ARC Centre of Excellence

2005 – Biotechnology Entrepreneur Young Achievement Australia Award

Top five publications

Chen X., Jia B., Saha J., Cai B., Stokes N., Qiao Q., Wang Y., Shi Z., Gu M. (2012) Broadband enhancement in thin-film amorphous silicon solar cells enabled by nucleated silver nanoparticles, Nano Letters 12, 2187-2192. (Impact factor 13.2, 3 citations)

Chen J., Wang Y., Jia B., Geng T., Li X., Feng L., Hu J., Liang B., Zhang X., Gu M., Zhuang S. (2011) Observation of the inverse Doppler effect in negative-index materials at optical frequencies, Nature Photonics 5:239–245. (Impact factor 29.3, 6 citations)

Jia B., Buso D., Li J., Gu M. (2010) Functional 3D photonic crystals fabricated in highly nonlinear quantum dot nanocomposites, Advanced Materials 22(22):2463-2467. (Impact factor 13.9, 4 citations)

Jia B., Kang H., Li J., Gu M. (2009) Use of radially polarized beams in 3D photonic crystal fabrication with the two-photon polymerization method, Optics Letters 34:1918-1920. (Impact factor 3.3, 18 citations)

Li J., Jia B., Bullen C., Serbin J., and Gu M. (2007) Spectral redistribution and optical gain in spontaneous emission from quantum-dot-infiltrated 3D woodpile photonic crystals for telecommunications, Advanced Materials 19:3276-3080. (Impact factor 13.9, 23 citations)

Images:

Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)
Click image for hi-res. Photo: Dr Baohua Jia, Swinburne University of Technology (credit: L’Oréal Australia/sdpmedia.com.au)

Media contacts:

  • Media in Australia contact:
    Natalie Perkov, Corporate Communications Manager, L’Oréal Australia on +61 (421) 007 911, nperkov@au.loreal.com,
    or Niall Byrne, Creative Director, Science in Public on niall@scienceinpublic.com.au +61 (417) 131 977
  • Media in New Zealand contact:
    Deborah Pead. Pead PR +64 (9) 918 55 50 +64 (21) 61 29 19 deborah@peadpr.co.nz
    or Tanya Abbott, Communications Manager, L’Oréal New Zealand, +64 (21) 67 84 97, tabbott@nz.loreal.com