All-Thin-Film Tandem Cells Based on Liquid Phase Crystallized Silicon and Perovskites

• Published in: IEEE journal of photovoltaics Vol. 9; no. 3; pp. 621 - 628
• Main Authors: Trahms, Martina, Jost, Marko, Trinh, Cham Thi, Preissler, Natalie, Albrecht, Steve, Schlatmann, Rutger, Rech, Bernd, Amkreutz, Daniel
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.05.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorptance; Absorptivity; Crystallization; Current loss; Electrical properties; Glass; Incident light; Liquid phase crystallization (LPC); Liquid phases; Open circuit voltage; Optical device fabrication; Optical measurement; Optical properties; Optical variables measurement; perovskite solar cells; Perovskites; Photovoltaic cells; Photovoltaic systems; Silicon; Solar cells; State of the art; Substrates; tandem devices; thin film photovoltaics; Thin films
• ISSN: 2156-3381; 2156-3403
• DOI: 10.1109/JPHOTOV.2019.2896995

Combining the emerging perovskite solar cell technology with existing silicon approaches in a tandem cell design offers the possibility for new low-cost high-performance devices. In this study, the potential of liquid phase crystallized silicon (LPC-Si) solar cells as a bottom cell in an all-thin-film tandem device is investigated. By optimizing the current output of a four terminal tandem using optical simulations and state-of-the-art electrical properties of the top and bottom cells, we show that an efficiency of 23.3<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> can be reached, where 7.2<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> are attributed to the LPC-Si bottom cell. Including the potential of future developments of both sub cells, efficiencies of over 28<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula> are estimated. Electrical and optical measurements of the bottom cell are performed by attaching a perovskite and a cutoff filter to the front side of the interdigitated back contacted LPC-Si cells. The measurements using a cutoff filter show a high impact of the filtered incident light spectrum on the open circuit voltage of the LPC-Si cell. A comparison of the simulated and measured absorptance shows that especially the optical properties of the transparent conductive oxides and recombination losses in the LPC-Si cause high current losses. Combining the measured data of the filtered LPC-Si cells and the semitransparent perovskite cells, yields a realistic estimation for the efficiency of a state-of-the-art four-terminal tandem device of 19.3<inline-formula><tex-math notation="LaTeX">\%</tex-math></inline-formula>.