Review—On the Origin of Diminishing Radiative Lifetime of Mn4+ in Complex Fluoride Phosphors with Temperature

ABSTRACTThe synthesis of nc-Si by reactive evaporation of SiO and subsequent thermal induced phase separation is reported. The size control of nc-Si is realized by evaporation of SiO/SiO2 superlattices. By this method an independent control of crystal size and density is possible. The phase separation of SiO into SiO2 and nc-Si in the limit of ultrathin layers is investigated. Different steps of this phase separation are characterized by photoluminescence, infrared absorption and transmission electron microscopy measurements. The strong room temperature luminescence of nc-Si shows a strong blueshift of the photoluminescence signal from 850 to 750 nm with decreasing crystal size. Several size dependent properties of this luminescence signal, like decreasing radiative lifetime and increasing no-phonon transition properties with decreasing crystal size are in good agreement with the quantum confinement model. Er doping of the nc-Si shows an enhancement of the Er luminescence at 1.54 μm by a factor of 5000 compared to doped SiO2 layers. The decreasing transfer time for the nc-Si to Er transition with decreasing crystal size can be understood as additional proof of increasing recombination probability within the nc-Si for decreasing crystal size.

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Radiative properties of quantum emitters in boron nitride from excited state calculations and Bayesian analysis

npj Computational Materials ◽

10.1038/s41524-021-00544-2 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Shiyuan Gao ◽

Hsiao-Yi Chen ◽

Marco Bernardi

Keyword(s):

Boron Nitride ◽

Density Functional ◽

Single Photon ◽

Radiative Lifetime ◽

Radiative Properties ◽

Data Set ◽

Radiative Lifetimes ◽

Emission Energy ◽

Single Photon Emitters ◽

Quantum Emitters

AbstractPoint defects in hexagonal boron nitride (hBN) have attracted growing attention as bright single-photon emitters. However, understanding of their atomic structure and radiative properties remains incomplete. Here we study the excited states and radiative lifetimes of over 20 native defects and carbon or oxygen impurities in hBN using ab initio density functional theory and GW plus Bethe-Salpeter equation calculations, generating a large data set of their emission energy, polarization and lifetime. We find a wide variability across quantum emitters, with exciton energies ranging from 0.3 to 4 eV and radiative lifetimes from ns to ms for different defect structures. Through a Bayesian statistical analysis, we identify various high-likelihood charge-neutral defect emitters, among which the native VNNB defect is predicted to possess emission energy and radiative lifetime in agreement with experiments. Our work advances the microscopic understanding of hBN single-photon emitters and introduces a computational framework to characterize and identify quantum emitters in 2D materials.

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Single-molecule spectromicroscopy: a route towards sub-wavelength refractometry

Faraday Discussions ◽

10.1039/c5fd00086f ◽

2015 ◽

Vol 184 ◽

pp. 263-274 ◽

Cited By ~ 15

Author(s):

T. A. Anikushina ◽

M. G. Gladush ◽

A. A. Gorshelev ◽

A. V. Naumov

Keyword(s):

Refractive Index ◽

Single Molecule ◽

Low Temperatures ◽

Radiative Lifetime ◽

Spatially Resolved ◽

Local Fluctuations ◽

Novel Approach ◽

Spectral Linewidth ◽

Spatial Fluctuations ◽

Sub Wavelength

We suggest a novel approach for spatially resolved probing of local fluctuations of the refractive index n in solids by means of single-molecule (SM) spectroscopy. It is based on the dependence T1(n) of the effective radiative lifetime T1 of dye centres in solids on n due to the local-field effects. Detection of SM zero-phonon lines at low temperatures gives the values of the SM natural spectral linewidth (which is inversely proportional to T1) and makes it possible to reveal the distribution of the local n values in solids. Here we demonstrate this possibility on the example of amorphous polyethylene and polycrystalline naphthalene doped with terrylene. In particular, we show that the obtained distributions of lifetime limited spectral linewidths of terrylene molecules embedded into these matrices are due to the spatial fluctuations of the refractive index local values.

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