Perovskite-CuInSe2 2-Terminal Tandem Solar Cells and Modules with Scalable Processes
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Author
Kothandaraman, Radha
Krause, Maximilian
Lai, Huagui
Nishiwaki, Shiro
Siegrist, Severin
Dussouillez, Marion
Walter, Arnaud
Jeangros, Quentin
Carron, Romain
Nath Tiwari, Ayodhya
Abstract
Thin-film perovskite-based tandem solar cells (TSCs) have gained immense research attention due to their low-cost potential, roll-to-roll processing capability, and their remarkable power conversion efficiency (PCE). In particular, the perovskite-CI(G)S (Copper Indium Gallium Selenide) material systems/architecture display promising potential to realize highly efficient and stable all-thin-film tandem solar cells/modules. The low bandgap of CIS bottom cells (1 eV) relaxes the bandgap requirement of the perovskite top cell to around 1.6 eV, which is more stable than their wide-bandgap counterpart (1.7 to 1.8 eV), and the CIS bottom cells have superior stability compared to thin-film narrow bandgap Pb-Sn perovskite bottom cells. However, the degradation of the perovskite absorber at elevated processing temperature (over 130 °C) due to the undesirable interfacial reaction with the i-ZnO/IZO layer (Zinc oxide/Indium Zinc oxide) in the CI(G)S solar cell structure, limits the thermal budget of the perovskite absorber and compromises their optoelectronic quality. Further, for tandem module demonstration, it is important to mitigate the shunting of the tandem subcells through the recombination layer. In this contribution, we first understand the origin of the thermal-induced degradation of the perovskite absorber during their processing steps at the perovskite-CI(G)S interface. To circumvent this degradation, we develop a low-temperature (120 °C) process for the fabrication of MA-free perovskite layer with excellent optoelectronic properties to make them compatible to CI(G)S solar cell structure. We also employ a fully scalable processing sequence for the tandem stack with hole transport bilayer (NiOx/MeO2PACz) deposited using a combination of sputtering and blade coating processes, perovskite by blade-coating process, and electron transport layer stack by vacuum-based scalable methods. Further, we develop a novel all-laser-based interconnection method for monolithic interconnection in tandem modules to realize perovskite-CI(G)S 2T tandem modules with an efficiency close to 18% efficiency. The interconnection scheme proposed here is also suitable for other thinfilm tandem modules and promises a low cell-to-module derate.
Publication Reference
EU PVSEC 2023, 2DV.1.26, p. 020146-001 - 020146-001
Year
2023-09-01