Hot-carrier cooling and photoinduced refractive index changes in organic–inorganic lead halide perovskites

By Michael B. Price, J. Butkus, Tom C Jellicoe, A. Sadhanala, A. Briane, J. Halpert, K. Broch, J. Hodgkiss, R. Friend, F. Deschler. Nature Communications, 2015

614 citations recorded by the source corpus.

Metal-halide perovskites are at the frontier of optoelectronic research due to solution processability and excellent semiconductor properties. Here we use transient absorption spectroscopy to study hot-carrier distributions in CH3NH3PbI3 and quantify key semiconductor parameters. Above bandgap, non-resonant excitation creates quasi-thermalized carrier distributions within 100 fs. During carrier cooling, a sub-bandgap transient absorption signal arises at ∼1.6 eV, which is explained by the interplay of bandgap renormalization and hot-carrier distributions. At higher excitation densities, a ‘phonon bottleneck’ substantially slows carrier cooling. This effect indicates a low contribution from inelastic carrier-impurity or phonon–impurity scattering in these polycrystalline materials, which supports high charge-carrier mobilities. Photoinduced reflectivity changes distort the shape of transient absorption spectra and must be included to extract physical constants. Using a simple band-filling model that accounts for these changes, we determine a small effective mass of mr=0.14 mo, which agrees with band structure calculations and high photovoltaic performance. The use of organic–inorganic metal-halide perovskites in hot-carrier devices depends on deepening the understanding of photoexcitations in these materials. Here, Price et al. use transient absorption spectroscopy to study hot-carrier distributions in CH3NH3PbI3and quantify key semiconductors parameters.

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/6ae849bc492d9af41890561135ec160320d0675a

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Citations in the corpus

• Charge-Carrier Dynamics in Organic-Inorganic Metal Halide Perovskites. (2016, background): “Later studies have interpreted the complex transient absorption lineshape around the band edge in terms of bandgap renormalization, Burstein-Moss effects, and charge-carrier cooling (63, 99).”