Understanding the Performance-Limiting Factors of Cs2AgBiBr6 Double-Perovskite Solar Cells

Giulia Longo*, Suhas Mahesh, Leonardo R. V. Buizza, Adam D. Wright, Alexandra J. Ramadan, Mojtaba Abdi-Jalebi, Pabitra K. Nayak, Laura M. Herz, Henry J. Snaith

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review

39 Citations (Scopus)

Abstract

Double perovskites have recently emerged as possible alternatives to lead-based halide perovskites for photovoltaic applications. In particular, Cs2AgBiBr6 has been the subject of several studies because of its environmental stability, low toxicity, and its promising optoelectronic features. Despite these encouraging features, the performances of solar cells based on this double perovskite are still low, suggesting severe limitations that need to be addressed. In this work we combine experimental and theoretical studies to show that the short electron diffusion length is one of the major causes for the limited performance of Cs2AgBiBr6 solar cells. Using EQE measurements on semitransparent Cs2AgBiBr6 solar cells we estimate the electron diffusion length to be only 30 nm and corroborated this value by terahertz spectroscopy. By using photothermal deflection spectroscopy and surface photovoltage measurements we correlate the limited electron diffusion length with a high density of electron traps. Our findings highlight important faults affecting this double perovskite, showing the challenges to overcome and hinting to a possible path to improve the efficiency of Cs2AgBiBr6 solar cells.
Original languageEnglish
Pages (from-to)2200-2207
Number of pages8
JournalACS Energy Letters
Volume5
Issue number7
Early online date4 Jun 2020
DOIs
Publication statusPublished - 10 Jul 2020

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