TY - JOUR
T1 - Multiphoton absorption order of CsPbBr3 as determined by wavelength-dependent nonlinear optical spectroscopy
AU - Saouma, Felix O.
AU - Stoumpos, Constantinos C.
AU - Kanatzidis, Mercouri G.
AU - Kim, Yong Soo
AU - Jang, Joon I.
N1 - Funding Information:
The work was supported by the Basic Science Research Program (2017R1D1A1B03035539 and 2015R1D1A3A03019609), Priority Research Centers Program (2009-0093818), and the Basic Research Lab Program (2014R1A4A1071686) through the National Research Foundation of Korea (NRF), funded by the Korean government. Work at Northwestern University was supported by Grant SC0012541 from the U.S. Department of Energy, Office of Science (sample synthesis, purificantion, and characterization).
PY - 2017/10/5
Y1 - 2017/10/5
N2 - 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.
AB - 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.
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U2 - 10.1021/acs.jpclett.7b02286
DO - 10.1021/acs.jpclett.7b02286
M3 - Article
C2 - 28944676
AN - SCOPUS:85032628484
VL - 8
SP - 4912
EP - 4917
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 19
ER -