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arXiv · 1908.04881

Effect of Dimensionality on the Optical Absorption Properties of CsPbI$_3$ Perovskite Nanocrystals

Albert Liu·Luiz G. Bonato·Francesco Sessa·Diogo B. Almeida·Erik Isele·Gabriel Nagamine·Luiz F. Zagonel·Ana F. Nogueira·Lazaro A. Padilha·Steven T. Cundiff
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Abstract

The band-gaps of CsPbI$_3$ perovskite nanocrystals are measured by absorption spectroscopy at cryogenic temperatures. Anomalous band-gap shifts are observed in CsPbI$_3$ nanocubes and nanoplatelets, which are modeled accurately by band-gap renormalization due to lattice vibrational modes. We find that decreasing dimensionality of the CsPbI$_3$ lattice in nanoplatelets greatly reduces electron-phonon coupling, and dominant out-of-plane quantum confinement results in a homogeneously broadened absorption lineshape down to cryogenic temperatures. An absorption tail forms at low-temperatures in CsPbI$_3$ nanocubes, which we attribute to shallow defect states positioned near the valence band-edge.

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Albert Liu, Luiz G. Bonato, Francesco Sessa, Diogo B. Almeida, Erik Isele, Gabriel Nagamine, Luiz F. Zagonel, Ana F. Nogueira, Lazaro A. Padilha, Steven T. Cundiff. 2019-10-11. Effect of Dimensionality on the Optical Absorption Properties of CsPbI$_3$ Perovskite Nanocrystals. https://doi.org/10.1063/1.5124399

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