Multiphoton absorption order of CsPbBr3 as determined by wavelength-dependent nonlinear optical spectroscopy

Felix O. Saouma, Constantinos C. Stoumpos, Mercouri G Kanatzidis, Yong Soo Kim, Joon I. Jang

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

CsPbBr3 is a direct-gap semiconductor where optical absorption takes place across the fundamental bandgap, but this all-inorganic halide perovskite typically exhibits above-bandgap emission when excited over an energy level, lying above the conductionband minimum. We probe this bandgap anomaly using wavelength-dependent multiphoton absorption spectroscopy and find that the fundamental gap is strictly twophoton forbidden, rendering it three-photon absorption (3PA) active. Instead, two-photon absorption (2PA) commences when the two-photon energy is resonant with the optical gap, associated with the level causing the anomaly. We determine absolute nonlinear optical dispersion over this 3PA-2PA region, which can be explained by two-band models in terms of the optical gap. The polarization dependence of 3PA and 2PA is also measured and explained by the relevant selection rules. CsPbBr3 is highly luminescent under multiphoton absorption at room temperature with marked polarization and wavelength dependence at the 3PA-2PA crossover and therefore has potential for nonlinear optical applications.

Original languageEnglish
Pages (from-to)4912-4917
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume8
Issue number19
DOIs
Publication statusPublished - Jan 1 2017

ASJC Scopus subject areas

  • Materials Science(all)

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