Three-photon Near-infrared Quantum Research Articles

Spectroscopic properties and dynamic analysis of three-photon quantum-cutting luminescence in Er doped NaYF4 nanoparticles

Spectroscopic properties and dynamic analysis play a significant role during the design and development of novel luminescent materials. In this work, Er3+ doped NaYF4 nanoparticles were successfully synthesized by coprecipitation method. The absorption spectrum, fluorescence spectra, and decay curves were measured at room temperature. The spectroscopic properties, including the radiative and nonradiative transition probability, fluorescent branch ratio, cross-relaxation rate and the fluorescence lifetime, were calculated based on the Judd-Ofelt theory. Furthermore, the rate equation models were established to analyze the dynamic processes of three-photon near-infrared quantum cutting luminescence. The time-dependent population densities of excited levels of Er3+ ions were simulated and the theoretical quantum efficiency was calculated to be 252.40%, which is consistent with our experimental results.

Three-photon near-infrared quantum cutting in β-NaGdF4:Yb3+

Three-photon near-infrared quantum cutting of Gd3+ to Yb3+ was observed in β-NaGdF4:Yb3+ for the first time. The consistency between theoretical predictions by applying rate equations in the quantum cutting model and experimental results obtained from fluorescence spectra successfully confirmed the occurrence of three-photon near-infrared quantum cutting. The strong interaction between Yb3+ ions is a key factor affecting energy transfer. Maximum energy transfer efficiency and the quantum efficiency can reach 98.2% and 296.5%, respectively. High-efficiency three-photon near-infrared quantum cutting has an admirably promising application prospect in improving the photoelectric conversion efficiency of c-Si solar cells.

Enhancement of three-photon near-infrared quantum cutting in β-NaYF4:Er3+ nanoparticles by Ag nanocubes

The near-infrared (NIR) quantum cutting (QC) nanoparticles (NPs) β-NaYF4:Er3+ are prepared by coprecipitation method. Three-photon NIR QC luminescence at 1520 nm (4I13/2 → 4I15/2) is obtained under the excitation of 519 nm (4I15/2 → 2H11/2). The corresponding QC efficiency ηQC calculated from the luminescence decay curves reaches as 242.59%. Furthermore, three-photon NIR QC luminescence is enhanced by the localized surface plasmon resonance of Ag nanocubes (NCs). The influence of Ag NCs concentration on three-photon QC luminescence is investigated, and the results show that the optimal concentration of Ag NCs is 0.10% with the enhancement factor reached a maximum as 2.86. Our study may have potential application as a QC layer to improve the photovoltaic conversion efficiency of germanium (Ge) solar cells.

Sequential three-photon near-infrared quantum cutting in transparent fluorogermanate glass-ceramics containing LaF_3:Tm^3+ nanocrystals

Transparent fluorogermanate glass-ceramics singly doped with 0.25 mol.%Tm3+ have been prepared through melt quenching and sequential thermal treatment. The structure and composition of the glass-ceramics have been characterized by means of X-ray diffraction, Raman spectroscopy and transmission electron microscopy. Efficient three-step sequential three-photon near-infrared (NIR) quantum cutting has been demonstrated, where an absorbed blue photon at 468 nm could be cut into three NIR photons at 1190, 1462 and 1800 nm, respectively. The underlying mechanism has been analyzed in terms of the static and dynamic spectra measurements. Based on the experimental data and theoretical consideration, an internal quantum yield has been estimated to be about 160%. Further development of such a triply-cutting material might explore a way to design high efficient photonic devices, which harvest more photons emitted than absorbed in the excitation process.

Broadband three-photon near-infrared quantum cutting in Tm3+ singly doped YVO4

An efficient three-photon near-infrared (NIR) quantum cutting (QC) is reported in Tm3+ singly doped YVO4 polycrystalline phosphors, where an optimized content of Tm3+ is determined to be 1.0 mol. %. Upon the absorption of a visible photon around 473 nm, three NIR photons emitting at 1180, 1479, and 1800 nm can be obtained efficiently by the sequential three-step radiative transitions of Tm3+. The underlying mechanisms are analyzed in terms of the steady and dynamic fluorescence spectra measurements. Internal quantum yield is calculated to be 161.8% as a theoretical value when luminescence quenching due to defect species can be overcome. In addition, the broadband ultraviolet (UV)-excited [VO4]3− can strongly sensitize the 1G4 level of Tm3+ in the wavelength range likely from 250 to 360 nm, greatly increasing the UV photo-response and NIR fluorescent intensity of Tm3+. The further development of this broadband three-photon NIR QC material would explore the new route to improve the photo-response of novel photoelectronic devices, particularly in 250–360 nm.

Three-photon near-infrared quantum cutting in Tm3+-doped transparent oxyfluoride glass ceramics

Efficient three-step sequential three-photon near-infrared (NIR) quantum cutting in Tm3+-doped transparent oxyfluoride glass ceramics has been demonstrated, where an absorbed blue photon could be cut into three NIR photons at 1190, 1460, and 1800 nm with quantum yield greater than unity. On the basis of static and dynamic photoemission, monitored excitation, and time-resolved fluorescence spectra, we investigate in detail the underlying optoelectronic mechanism. Further development of an efficient triply-cutting material might open up a path towards ultra-efficient photonic devices, which enables more photons emitted than absorbed in the excitation process.

Enhanced three-photon near-infrared quantum splitting in β-NaYF4:Ho3+ by codoping Yb3+

An efficient three-step sequential three-photon near-infrared (NIR) quantum splitting (QS), involving the emission of three NIR photons from an absorbed ultraviolet (UV) photon in β-NaYF4:Ho3+, has been demonstrated. Codoping Yb3+ can increase the NIR emissions significantly through the first- and second-step cross-relaxation. The involved mechanisms of three-step NIR QS in Ho3+-Yb3+ have been well demonstrated by the static and dynamic photoluminescence, monitored excitation and time-resolved fluorescence spectra. An internal quantum yield (QY) of 246% for the Yb3+ codoped β-NaYF4:Ho3+ is estimated on the basis of experimental data and theoretical considerations, which is much more than the total QY of 124% for the β-NaYF4:Ho3+ three-photon NIR QS. This research may open up promising new perspectives for designing efficient photonic devices.

Sequential three-step three-photon near-infrared quantum splitting in β-NaYF4:Tm3+

We report on sequential three-step three-photon near-infrared (NIR) quantum splitting in Tm3+-doped β-NaYF4, where an incident blue photon around 470 nm is split into three NIR photons (1165, 1466, and 1800 nm). The underlying mechanism is analyzed by means of static and dynamic photoemission spectroscopy. Here, an experimental total quantum yield of ∼32% is obtained. When quenching due to residual hydroxyl groups and other defect species can be overcome, numerical analyses indicate a theoretical maximum quantum yield of 158%, suggesting application in efficient spectral converters.

Three-photon near-infrared quantum splitting in β-NaYF4:Ho3+

We report on three-step sequential three-photon near-infrared (NIR) quantum splitting in β-NaYF4:Ho3+, where one absorbed ultraviolet photon is split into three NIR photons with wavelengths 850, 1015, and 1180 nm. The underlying mechanism is analyzed by static and dynamic photoemission and excitation spectroscopy. An internal quantum yield of 124% is estimated on the basis experimental data and theoretical considerations. Further development of an efficient triply splitting NIR phosphor might open up an approach in achieving efficient photonic devices, which enables more photons emitted than absorbed in the excitation process.