Dr Xiaolei Liu


  • Research Associate in Thin Film Solar Cells


Dr Liu obtained a PhD degree in Photovoltaic Engineering at the University of New South Wales (UNSW), Australia under the supervision of Prof Martin Green, where his research focused on CZTS solar cells. After graduation from UNSW, Xiaolei was appointed as a Research Associate (2016-2017) at University College London, where he investigated CIGS and perovskite solar cells. As a creative and high-achieving researcher with research experience across CZTS, CIGS and perovskite solar cells, Xiaolei developed a track record on thin film solar cells and produced two patents (one as an inventor and the other as a main contributor), eleven peer reviewed journal papers and five conference papers. The two patents are: (i) the use of an ultra-thin Ag layer at the CZTS/Mo back contact interface coupled with rapid thermal anneal leading to improvement in device performance. This original work has led to a filed patent (patent No. PCT/AU2014/001101); and (ii) the application of a graphene layer between the Mo back contact and the CZTS absorber to engineer the CZTS/Mo interface. A patent, for which he is an inventor, has been applied for the creative work at the CZTS/Mo interface (patent No. PCT/AU2016/050835). Xiaolei published a review paper of The current status and future prospects of kesterite solar cells: a brief review in the prestigious journal of Progress in Photovoltaics: Research and Applications in the photovoltaic field (228 citations). This review paper summarizes the challenges and promise of kesterite devices and synthesizes the observations to identify new pathways to highly efficient kesterite solar cells in future research.


Dr Liu was awarded a Postdoctoral Writing Fellowship (October 2015 - December 2015) by the Faculty of Engineering, University of New South Wales, Australia.



Main research interests

  • CdTe, CIGS, CZTSSe and Perovskite Solar Cells
  • Device Simulation
  • Machine learning, natural language processing


1)    Xiaolei Liu, Yu Feng, Hongtao Cui, Fangyang Liu, Xiaojing Hao, Gavin Conibeer, David B. Mitzi, and Martin Green, The current status and future prospects of kesterite solar cells: a brief review. Progress in Photovoltaics: Research and Applications, 2016, DOI: 10.1002/pip.2741.

2)    Xiaolei Liu, Hongtao Cui, Charlie Kong, Xiaojing Hao, Yidan Huang, Fangyang Liu, Ning Song, Gavin Conibeer, and Martin Green, Rapid thermal annealed Molybdenum back contact for Cu2ZnSnS4 thin film solar cells. Applied Physics Letters, 2015, 106(13): p. 131110.

3)    Xiaolei Liu, Hongtao Cui, Wei Li, Ning Song, Fangyang Liu, Gavin Conibeer, and Xiaojing Hao, Improving Cu2ZnSnS4 (CZTS) solar cell performance by an ultrathin ZnO intermediate layer between CZTS absorber and Mo back contact. physica status solidi (RRL) - Rapid Research Letters, 2014, 8(12): p. 966-970.

4)    Xiaolei Liu, Yidan Huang, Jae Yun, Xiaoming Wen, Zhong Lu, Tian Zhang, Hongtao Cui, Wei Li, Chang-Yeh Lee, Song Xu, Xiaojing Hao, and Gavin Conibeer, Characterization of a Cu2ZnSnS4 solar cell fabricated by sulfurization of metallic precursor Mo/Zn/Cu/Sn, Physica Status Solidi A, 2015, DOI: 10.1002/pssa.201431942.

5)    Hongtao Cui, Xiaolei Liu, Fangyang Liu, Xiaojing Hao, Ning Song, and Chang Yan, Boosting Cu2ZnSnS4 solar cells efficiency by a thin Ag intermediate layer between absorber and back contact. Applied Physics Letters, 2014, 104(4): p. 041115.

6)    Wei Li, Xiaolei Liu, Hongtao Cui, Shujuan Huang, and Xiaojing Hao, The role of Ag in (Ag,Cu)2ZnSnS4 thin film for solar cell application. Journal of Alloys and Compounds, 2015, 625: p. 277-283. 

7)    Xiaolei Liu, Hongtao Cui, Xiaojing Hao, Shujuan Huang, Gavin Conibeer, and Martin Green, The effect of vacuum thermal annealing on the molybdenum bilayer back contact deposited by radio-frequency magnetron sputtering for chalcogenide and kesterite based solar cells. Journal of the Korean Physical Society, 2017, 71: p. 968.