The optical and electronic properties of Bridgman grown single crystals of the wide-bandgap semiconducting defect halide perovskites A3M2I9 (A = Cs, Rb; M = Bi, Sb) have been investigated. Intense Raman scattering was observed at room temperature for each compound, indicating high polarizability and strong electron–phonon coupling. Both low-temperature and room-temperature photoluminescence (PL) were measured for each compound. Cs3Sb2I9 and Rb3Sb2I9 have broad PL emission bands between 1.75 and 2.05 eV with peaks at 1.96 and 1.92 eV, respectively. The Cs3Bi2I9 PL spectra showed broad emission consisting of several overlapping bands in the 1.65–2.2 eV range. Evidence of strong electron–phonon coupling comparable to that of the alkali halides was observed in phonon broadening of the PL emission. Effective phonon energies obtained from temperature-dependent PL measurements were in agreement with the Raman peak energies. A model is proposed whereby electron–phonon interactions in Cs3Sb2I9, Rb3Sb2I9, and Cs3Bi2I9 induce small polarons, resulting in trapping of excitons by the lattice. The recombination of these self-trapped excitons is responsible for the broad PL emission. Finally, Rb3Bi2I9, Rb3Sb2I9, and Cs3Bi2I9 exhibit high resistivity and photoconductivity response under laser photoexcitation, indicating that these compounds possess potential as semiconductor hard radiation detector materials.
McCall, Kyle M., et al. "Strong Electron–Phonon Coupling and Self-Trapped Excitons in the Defect Halide Perovskites A<sub>3</sub>M<sub>2</sub>I<sub>9</sub> (A = Cs, Rb; M = Bi, Sb)." Chemistry of Materials, vol. 29, no. 9, Apr. 2017. https://doi.org/10.1021/acs.chemmater.7b01184
McCall, Kyle M., Stoumpos, Constantinos C., Kostina, Svetlana S., Kanatzidis, Mercouri G., & Wessels, Bruce W. (2017). Strong Electron–Phonon Coupling and Self-Trapped Excitons in the Defect Halide Perovskites A<sub>3</sub>M<sub>2</sub>I<sub>9</sub> (A = Cs, Rb; M = Bi, Sb). Chemistry of Materials, 29(9). https://doi.org/10.1021/acs.chemmater.7b01184
McCall, Kyle M., Stoumpos, Constantinos C., Kostina, Svetlana S., et al., "Strong Electron–Phonon Coupling and Self-Trapped Excitons in the Defect Halide Perovskites A<sub>3</sub>M<sub>2</sub>I<sub>9</sub> (A = Cs, Rb; M = Bi, Sb)," Chemistry of Materials 29, no. 9 (2017), https://doi.org/10.1021/acs.chemmater.7b01184
@article{osti_1494819,
author = {McCall, Kyle M. and Stoumpos, Constantinos C. and Kostina, Svetlana S. and Kanatzidis, Mercouri G. and Wessels, Bruce W.},
title = {Strong Electron–Phonon Coupling and Self-Trapped Excitons in the Defect Halide Perovskites A<sub>3</sub>M<sub>2</sub>I<sub>9</sub> (A = Cs, Rb; M = Bi, Sb)},
annote = {The optical and electronic properties of Bridgman grown single crystals of the wide-bandgap semiconducting defect halide perovskites A3M2I9 (A = Cs, Rb; M = Bi, Sb) have been investigated. Intense Raman scattering was observed at room temperature for each compound, indicating high polarizability and strong electron–phonon coupling. Both low-temperature and room-temperature photoluminescence (PL) were measured for each compound. Cs3Sb2I9 and Rb3Sb2I9 have broad PL emission bands between 1.75 and 2.05 eV with peaks at 1.96 and 1.92 eV, respectively. The Cs3Bi2I9 PL spectra showed broad emission consisting of several overlapping bands in the 1.65–2.2 eV range. Evidence of strong electron–phonon coupling comparable to that of the alkali halides was observed in phonon broadening of the PL emission. Effective phonon energies obtained from temperature-dependent PL measurements were in agreement with the Raman peak energies. A model is proposed whereby electron–phonon interactions in Cs3Sb2I9, Rb3Sb2I9, and Cs3Bi2I9 induce small polarons, resulting in trapping of excitons by the lattice. The recombination of these self-trapped excitons is responsible for the broad PL emission. Finally, Rb3Bi2I9, Rb3Sb2I9, and Cs3Bi2I9 exhibit high resistivity and photoconductivity response under laser photoexcitation, indicating that these compounds possess potential as semiconductor hard radiation detector materials.},
doi = {10.1021/acs.chemmater.7b01184},
url = {https://www.osti.gov/biblio/1494819},
journal = {Chemistry of Materials},
issn = {ISSN 0897-4756},
number = {9},
volume = {29},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2017},
month = {04}}
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 531, Issue 1-2https://doi.org/10.1016/j.nima.2004.05.071
Vakulenko, Olegh V.; Gubanov, Victor O.; Kun, Stepan V.
International Conference on Optical Diagnostics of Materials and Devices for Opto-, Micro-, and Quantum Electronics, SPIE Proceedingshttps://doi.org/10.1117/12.306241