arXiv subjects

A. V. Emeline

Publications and source records attributed to A. V. Emeline.

4 recordsLinked to original sources

arXiv2020

Defect-related states in MAPbI$_3$ halide perovskite single crystals revealed by the photoluminescence excitation spectroscopy

The MAPbI$_3$ halide perovskite single crystals are studied at 5 K temperature using the photoluminescence excitation spectroscopy. Two non-interacting types of states are determined: bound excitons and defect-related states. Excitation of the crystal with light energy below the bound exciton resonance reveals the complex low-density defects emission, otherwise hidden by the emission of bound excitons. A way to separate these defect-related luminescence spectra is proposed, and the thorough study of this emission regime is carried out. The results of this study opens an area of low-density defects and dopants exploration in halide perovskite semiconductors.

cond-mat.mes-hall↗

arXiv2020

Amplified Spontaneous Emission and Random Lasing in MAPbBr$_3$ Halide Perovskite Single Crystals

Halide perovskites are a promising optical gain media with high tunability and simple solution synthesis. In this study, two gain regimes, namely amplified spontaneous emission and random lasing, are demonstrated in same MAPbBr$_3$ halide perovskite single crystal. For this, photoluminescence is measured at a temperature of 4 K with pulsed femtosecond pumping by UV light with a 80 MHz repetition rate. Random lasing is observed in areas of the sample where a random resonator was formed due to cracks and crystal imperfections. In more homogeneous regions of the sample, the dominant regime is amplified spontaneous emission. These two regimes are reliably distinguished by the line width, the mode structure, the growth of the intensity after the threshold, and the degree of polarization of the radiation. The spectral localization of the stimulated emission well below the bound exciton resonance raises a question concerning the origin of the emission in halide perovskite lasers.

physics.app-ph↗

arXiv2017

Microstructural analysis and optical properties of Cs2BiAgBr6 halide double perovskite single crystals

Single crystals of Cs2BiAgBr6 lead-free perovskite were grown by crystallization from supersaturated solution. According to characterization by XRD and EBSD methods the double perovskite single crystal are of the cubic Fm-3m symmetry with the lattice constant a = 11.20 Å. DFT predictions based on the single crystal X-ray diffraction analysis reveal that the material is an indirect band gap semiconductor. Low temperature (1.4 K) photoluminescence spectra demonstrate three broadened bands that correspond to two lowest computed indirect and one direct band-to-band transitions.

cond-mat.mes-hall↗

arXiv2017

Low inhomogeneous broadening of excitonic resonance in MAPbBr3 single crystals

We present optical study of MAPbBr3 single crystals grown from solution by inverse temperature crystallization method. Photoluminescence temperature dependence of narrow and isolated exciton resonance showed encouragingly low inhomogeneous broadening Γ ~ 0.5 meV, which is comparable to those of MBE-grown III-V heterostructures, indicating high quality of the solution-grown perovskite. Excitonic origin of the resonance was proved by its superlinear pump intensity dependence in contrast to the linear behavior of the defect-assisted recombination bands. In addition, for the first time phonon replicas were resolved in MAPbBr3 photoluminescence spectra and attributed to the known lattice vibrational modes by comparison with Raman scattering spectra.

cond-mat.mes-hall↗