Gianluca Coletti

Adjunct Professor – Program coordinator

We are at a critical turning point of the energy transition. Despite the pandemic, the global PV module market is expected to reach over 180 GW in 2021 and this on top of the more than 100 GW of PV modules shipped for the previous 3 years. More importantly, the PV industry is maturing quickly with a learning rate – the price reduction for each doubling of cumulative PV module shipments - of over 39% since 2006.

Research area

This aggressive development is uncommon and unique to the PV industry. My research contributes to this success story with a focus on solutions for today’s challenges and tomorrow’s innovations. We are working to improve the reliability and lifetime of conventional modules with fast and effective in-line techniques and material research. For the near future, we are surpassing today’s efficiency limit of single devices by adopting tandem PV technology. Increasing the efficiency and extending the lifetime of PV leads to further reduce the Levelized Cost of Electricity (LCOE), to accelerate the Energy Transition and the dominance of solar energy are our goals. With my colleagues at TNO Energy Transition, within the Solliance collaboration and with our industrial and academic partners, we aim to scale-up and demonstrate efficiencies beyond 30% with reliable and industrially relevant photovoltaic tandem modules.

Recent results

We made another step to overcome the technical challenges to combine the main-stream silicon technology with the newly researched transparent perovskite devices and confirmed the huge advantages of the tandem technology approach. We demonstrated that the tandem architecture can be further combined with bifacial technology to reach record efficiencies with knowledge and products already proven in the market.  A bifacial tandem device with power density passing the fundamental limit of silicon technology was published early in 2020. This has demonstrated to the international community that the next technology step should be the combination of low-cost high-efficiency tandem technology with bifacial modules.

The research carried out with PhD students at the University of New South Wales focus on two aspects of photovoltaic research.

On one hand the development of advanced two terminal tandem devices. Here the transport and passivation layers developed at TNO and high bandgap devices developed at UNSW have been combined for the first time with important results. The study enabled the better understanding of the properties needed to further research such layers.

On the other hand, the understanding of the route cause for defects affecting the performance of crystalline silicon solar cells have been further researched. Here the role of nitrogen in silicon and its effect on the long-term module degradation have been studied. In addition, the knowledge built at UNSW on advanced hydrogenation and employed to mitigate the light and elevated temperature induced degradation in silicon cells resulted in the grant of a joint project aiming at transferring this knowledge to the Dutch solar energy market and funded with a Topsector Energy subsidy of the Ministry of Economic Affairs and Climate Policy, implemented by Netherlands Enterprise Agency (RVO). This will enable further development and build knowledge to improve more effectively the energy yield of PV modules in environment with lower solar irradiation and lower operating temperature typical of Dutch environment.

On February 1st, 2020, Gianluca Coletti has been conferred with the title of Adjunct Professor in the School of Photovoltaic and Renewable Energy Engineering, Faculty of Engineering at the University of New South Wales, Sydney, Australia.

Since 2021 Gianluca Coletti is member of the editorial board of Solar Energy Materials & Solar Cells, ScienceDirect, Elsevier.

PhD supervision

  • Zhuangyi Zhou
  • Benjamin Phua

Top publications

  • Bifacial four-terminal perovskite/silicon tandem solar cells and modules, G Coletti, SL Luxembourg, LJ Geerligs, V Rosca, AR Burgers, Y Wu, ..., ACS Energy Letters 5 (5), 1676-1680 (2020)
  • Sensitivity of state‐of‐the‐art and high efficiency crystalline silicon solar cells to metal impurities, G Coletti, Progress in Photovoltaics: Research and Applications 21 (5), 1163-1170 (2013)
  • Impact of metal contamination in silicon solar cells, G Coletti, PCP Bronsveld, G Hahn, W Warta, D Macdonald, B Ceccaroli, ..., Advanced Functional Materials 21 (5), 879-890 (2011)
  • Effect of iron in silicon feedstock on p-and n-type multicrystalline silicon solar cells, G Coletti, R Kvande, VD Mihailetchi, LJ Geerligs, L Arnberg, EJ Øvrelid, Journal of applied physics 104 (10), 104913 (2008)
  • Millisecond minority carrier lifetimes in n-type multicrystalline silicon, A Cuevas, MJ Kerr, C Samundsett, F Ferrazza, G Coletti, Applied Physics Letters 81 (26), 4952-4954 (2002)


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