Stefaan DE WOLF

King Abdullah University of Science and Technology 

Keynote Speaker


​Stefaan De Wolf's expertise lies in the science and technology of photovoltaics for terrestrial applications. His research focuses on the fabrication of high-efficiency silicon- and perovskite-based solar cells, with specific attention to the fundamental understanding of interface structures and electrical contact formation, relevant to solar cells and electronic devices. He is also interested in applications related to photovoltaics for hot climates and multi-junction solar cells, aimed at the improved utilization of the full solar spectrum for electricity generation. He is Clarivate Highly Cited Researcher since 2019. 


Pathways to Efficient and Stable Perovskite/ Silicon Tandem Solar Cells

Stefaan De Wolf

King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE), Material Science and Engineering Program (MSE), Thuwal, 23955-6900, Saudi Arabia

Keywords: solar cells, photovoltaics, perovskites, silicon, clean energy

In the presentation, I will discuss the multiple ways how monolithic perovskite/silicon can be fabricated, built from textured silicon heterojunction solar cells, with an emphasis on solution processing of the perovskite top cell. Bulk and contact passivation of the perovskite are instrumental to obtain a high performance, which can be obtained through molecular additive engineering and the use of a range of contact passivation layers [1,2]. Examples of effective passivation strategies are the use of molecular films at the hole-collecting metal-oxide / perovskite interface [3] and the use of fluoride-based layers at the electron-collecting perovskite / C60 interface [4]. This will be followed by a discussion about the outdoor performance of such tandems [5], the need for robust and perovskite-compatible encapsulation to do so, and the first longer-term outdoor measurements [6]. I will then move on to discuss reliability aspects of such tandems under accelerated degradation tests such as damp-heat testing, including device-engineering strategies to pass such tests [7]. I will also discuss other failure mechanisms to be overcome for perovskite/silicon tandems such as mechanical failure due to top-contact delamination [8] and potential induced degradation [9]. I will conclude my talk with arguing how bifacial perovskite/silicon tandems aid in improved performance as well as stability, thanks to their reliance on narrow-bandgap perovskites for optimal performance [10,11].

[1] F.H. Isikgor, F. Furlan, J. Liu, E. Ugur, M.K. Eswaran, A.S. Subbiah, E. Yengel, M. De Bastiani, G.T. Harrison, S. Zhumagali, C.T. Howells, E. Aydin, M. Wang, N. Gasparini, T.G. Allen, A. Rehman, E. Van Kerschaver, D. Baran, I. McCulloch, T.D. Anthopoulos, U. Schwingenschlogl, F. Laquai, and S. De Wolf, Joule 5, 1566 (2021).
[2] J. Liu, E. Aydin, J. Yin, M. De Bastiani, F.H. Isikgor, A.u. Rehman, E. Yengel, E. Ugur, G.T. Harrison, Y. Gao, M. Wang, j.I. Khan, M. Babics, T.G. Allen, A.S. Subbiah, K. Zhu, X. Zheng, W. Yan, F. Xu, M.F. Salvador, O.M. Bakr, M. Lanza, T.D. Anthopoulos, O.F. Mohammed, F. Laquai, S. De Wolf, Joule 5, 3169 (2021).
[3] F.H. Isikgor, S. Zhumagali, L.V.T. Merino, M. De Bastiani, I. McCulloch, and S. De Wolf, Nature Rev. Mater. (2022).
[4] J. Liu, M. De Bastiani, E. Aydin, G.T. Harrison, Y. Gao, R.R. Pradhan, M.K. Eswaran, M. Mandal, W. Yan, A. Seitkhan, M. Babics, A.S. Subbiah, E. Ugur, F. Xu, L. Xu, M. Wang, A.u. Rehman, A. Razzaq, J. Kang, R. Azmi, A.A. Said, F.H. Isikgor, T.G. Allen, D. Andrienko, U. Schwingenschlogl, F. Laquai, and S. De Wolf, Science 377, 302 (2022).
[5] E. Aydin, T.G. Allen, M. De Bastiani, L. Xu, J. Avila, M. Salvador, E. Van Kerschaver, and S. De Wolf, Nature Energy 5, 851 (2020).
[6] M. De Bastiani, E. Van Kerschaver, A. Rehman, E. Aydin, F.H. Isikgor, A.J. Mirabelli, S. Zhumagali, E. Ugur, G.T. Harrison, T.G. Allen, B. Chen, Y. Hou, S. Shikin, Q. Jeangros, C. Ballif, E.H. Sargent, M.F. Salvador, and S. De Wolf, ACS Energy Lett. 6, 2944 (2021).
[7] R. Azmi, E. Ugur, A. Seithkan, F. Aljamaan, A.S. Subbiah, G.T. Harrison, J. Liu, M.I. Nugraha, M.K. Eswaran, M. Babics, Y. Chen, F. Xu, T.G. Allen, A.u. Rehman, C.-L. Wang, T.D. Anthopoulos, U. Schwingenschlogl, M. De Bastiani, E. Aydin, and S. De Wolf, Science 376, 73 (2022).
[8] M. De Bastiani, G. Armaroli, R. Jalmood, L. Ferlauto, X. Li, R. Tao, G.T. Harrison, M. Babics, E. Aydin, T.G. Allen, C. Combe, T. Kramer, G. Lubineau, D. Cavalcoli, and S De Wolf, ACS Energy Lett. 7, 827 (2022).
[9] L. Xu, J. Liu, W. Luo, N. Wehbe, A. Seitkhan, M. Babics, J. Kang, M. De Bastiani, E. Aydin, T.G. Allen, M. Alamer, W. Yan, F. Xu, A.u. Rehman, and S. De Wolf, Cell Rep. Phys. Sci. 3, 101026 (2022).
[10] M. De Bastiani, A.J. Mirabelli, Y. Hou, F. Grota, E. Aydin, T.G. Allen, J. Troughton, A.S. Subbiah, F.H. Isikgor, J. Liu, L. Xu, B. Chen, E. Van Kerschaver, D. Baran, M.F. Salvador, U.W. Paetzold, E.H. Sargent, and S. De Wolf, Nature Energy 6, 167 (2021).
[11] M. De Bastiani, A.S. Subbiah, M. Babics, E. Ugur, T.G. Allen, E. Aydin, and S. De Wolf, Joule 6, 1431 (2022).