Life on the Urbach Edge

Esma Ugur, Martin Ledinský, Thomas Allen, Jakub Holovský, Aleš Vlk, Stefaan De Wolf

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The Urbach energy is an expression of the static and dynamic disorder in a semiconductor and is directly accessible via optical characterization techniques. The strength of this metric is that it elegantly captures the optoelectronic performance potential of a semiconductor in a single number. For solar cells, the Urbach energy is found to be predictive of a material's minimal open-circuit-voltage deficit. Performance calculations considering the Urbach energy give more realistic power conversion efficiency limits than from classical Shockley-Queisser considerations. The Urbach energy is often also found to correlate well with the Stokes shift and (inversely) with the carrier mobility of a semiconductor. Here, we discuss key features, underlying physics, measurement techniques, and implications for device fabrication, underlining the utility of this metric.
Original languageEnglish (US)
Pages (from-to)7702-7711
Number of pages10
JournalThe Journal of Physical Chemistry Letters
StatePublished - Aug 12 2022

ASJC Scopus subject areas

  • General Materials Science


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