Modulation Of Upconversion Luminescence Research Articles

Influence of Host Lattice Ions on the Dynamics of Transient Multiband Upconversion in Yb-Er Codoped NaLnF4 and LiLnF4 Microcrystals (Ln: Y, Lu, Gd).

Inorganic host matrices provide a tunable luminescence environment for lanthanide ions, allowing for the modulation of upconversion luminescence (UCL) properties. AREF4 (A = alkali metal, RE = rare earth) have a low phonon energy and a high optical damage threshold, making them widely used as the host matrix for UCL materials. However, the impact mechanism of alkali metal ions and lanthanide lattice ions on transient UCL dynamics in AREF4 remains unclear. This study utilized a high-power nanosecond-pulsed laser at 976 nm to excite Yb-Er codoped NaLnF4 and LiLnF4 (Ln: Y, Lu, and Gd) microcrystals (MCs). All samples exhibit multiband emission, and the transient UC dynamics are discussed in detail. Compared with LiLnF4, NaLnF4 has higher UC efficiency and red to green (R/G) ratio. Lanthanide ions (Y, Lu, and Gd) affect the energy transfer (ET) distance in Yb-Er codoped systems, thereby altering UC efficiency and the R/G ratio. The energy level coupling between Gd3+ and Er3+ prolongs the duration of the UC emission. Specifically, the red emission lifetime of NaGdF4 is five times longer than that of NaYF4. Our research contributes to exploring excellent alternative host matrices for NaYF4 in the fields of rapid-response optoelectronic devices, micro-nano lasers, and stimulated emission depletion (STED) microscopy.

Efficient Reversible Upconversion Luminescence Modulation based on Photochromism of Lanthanides‐Doped BaMgSiO4 Glass Ceramics Toward Optical Storage Application

AbstractTransparent glass with photochromic and luminescent properties has recently garnered considerable interest in optical storage, while the photochromic transparent glass system is still limited. Herein, it is proposed that combining transparent glass matrix with photochromic nanocrystals is an efficient strategy to develop a broader range of photochromic luminescent glass systems. The Yb3+/Tb3+ co‐doped BaMgSiO4 glass ceramics are successfully prepared by a two‐step melt‐quenching approach followed by a thermal treatment in a reducing atmosphere. The glass ceramics exhibit high transparency and distinct coloration, showing a color change between colorless and pink by alternating irradiation between 365 nm ultraviolet light and 473 nm laser. The formation of color centers in the BaMgSiO4 nanoparticles drives the coloration of such glass ceramics. Based on their photochromic and photobleaching behavior, the efficient reversible upconversion luminescence modulation can be implemented with the maximum luminescence modulation rate of 79.83%. The excellent reproducibility and anti‐fatigue of such upconversion luminescence modulation demonstrate the promising application of Yb3+/Tb3+ co‐doped BaMgSiO4 glass ceramics as an optical storage medium.

Plasmonic Chiral Metasurface-Induced Upconverted Circularly Polarized Luminescence from Achiral Upconversion Nanoparticles.

Chirality induction, transfer, and manipulation have aroused great interest in achiral nanomaterials. Here, we demonstrate strong upconverted circularly polarized luminescence from achiral core-shell upconversion nanoparticles (UCNPs) via a plasmonic chiral metasurface-induced optical chirality transfer. The Yb3+-sensitized core-shell UCNPs with good dispersity exhibit intense upconversion luminescence of Tm3+ and Nd3+ through the energy transfer process. By spin-coating the core-shell UCNPs on this chiral metasurface, strong enhancement and circular polarization modulation of upconversion luminescence can be achieved due to resonant coupling between surface plasmons and upconversion nanoparticles. In the UCNPs-on-metasurface composite, a significant upconversion luminescence enhancement can be achieved with a maximum enhancement factor of 32.63 at 878 nm and an overall enhancement factor of 11.61. The luminescence dissymmetry factor of the induced upconverted circularly polarized luminescence can reach 0.95 at the emission wavelength of 895 nm. The UCNPs-on-metasurface composite yields efficient modulation for the emission intensity and polarization of UCNPs, paving new pathways to many potential applications in imaging, sensing, and anticounterfeiting fields.

Recent Development in Sensitizers for Lanthanide-Doped Upconversion Luminescence.

The attractive features of lanthanide-doped upconversion luminescence (UCL), such as high photostability, nonphotobleaching or photoblinking, and large anti-Stokes shift, have shown great potentials in life science, information technology, and energy materials. Therefore, UCL modulation is highly demanded toward expected emission wavelength, lifetime, and relative intensity in order to satisfy stringent requirements raised from a wide variety of areas. Unfortunately, the majority of efforts have been devoted to either simple codoping of multiple activators or variation of hosts, while very little attention has been paid to the critical role that sensitizers have been playing. In fact, different sensitizers possess different excitation wavelengths and different energy transfer pathways (to different activators), which will lead to different UCL features. Thus, rational design of sensitizers shall provide extra opportunities for UCL tuning, particularly from the excitation side. In this review, we specifically focus on advances in sensitizers, including the current status, working mechanisms, design principles, as well as future challenges and endeavor directions.

In-situ host-transition-induced upconversion luminescence modulation of ZrW2O7(OH)2·2H2O:Yb3+/Er3+ nanocrystals

Luminescence properties of upconverting nanomaterials are significantly influenced by host structures. Even though previous studies have demonstrated various modulation approaches of host structures on upconversion luminescence, in-situ host transition has been hardly realized. In this paper, we demonstrate in-situ host-transition-induced upconversion luminescence modulation based on ZrW 2 O 7 (OH) 2 ·2H 2 O:Yb 3+ /Er 3+ nanocrystals. Specifically, ZrW 2 O 7 (OH) 2 ·2H 2 O:Yb 3+ /Er 3+ could be decomposed into ZrO 2 :Yb 3+ /Er 3+ and WO 3 :Yb 3+ /Er 3+ nanocrystals due to the increased host temperature by the 980-nm-wavelength-laser-triggered photothermal heating. After the host transition, the red-to-green emission ratio of the prepared nanoparticles has been significantly increased, leading to an apparent color change in the upconversion light emission. The work is expected to open up unprecedented avenues for fluorescence anti-counterfeiting, optical encoding, and sensing applications. • Realize a convenient upconversion luminescence modulation. • Demonstrate in-situ host-transition of ZrW 2 O 7 (OH) 2 ·2H 2 O:Yb 3+ /Er 3+ nanocrystals. • Realize tunable emission colors from green to red only by laser treatment.

Tuning broadband up-conversion by precipitation of perovskite KMgF3 nanocrystals in fluorosilicate glasses

Co-doping of Yb3+ with Mn2+ is a promising way to realize broadband up-conversion (UC) luminescence. The tunable broadband emission has been widely demonstrated in crystal materials, but the research on Yb3+/Mn2+ co-doped transparent optical glass has been scare, especially in fluoride-based transparent glass ceramics (GC) that can realize the uniform ions incorporation and efficient UC emission. Herein, a series of Yb3+/Mn2+ activated transparent fluorosilicate GCs containing perovskite KMgF3 nanocrystals were successfully prepared, and the effect of heat-treatment process and/or Mn2+ ion content on the UC luminescence modulation has been investigated. Our results show that the spontaneous crystallized precursor sample exhibits only a green emission at ~538 nm, while additional orange-emitting band centered at ~613 nm is noticeable in the GCs with the gradual precipitation of KMgF3 nanocrystals after heat-treatment. The controllable luminescence can be assigned to the formation of Yb3+-Mn2+ dimers that are located in multiple coordination environments provided by the glass matrix and crystalized nanocrystals. In addition, the prepared GC samples exhibit excellent reversible emission characteristics during heating and cooling cycles. This research not only provides a new option to design desirable coordination environment for Yb3+-Mn2+ dimers, also helps to recognize the UC process in the transparent matrix in detail.

Binary Nanoparticle Superlattices for Plasmonically Modulating Upconversion Luminescence.

Engineering a facile and controllable approach to modulate the spectral properties of lanthanide-doped upconversion nanoparticles (UCNPs) is always an ongoing challenge. Herein, long-range ordered, distinct two-dimensional (2D) binary nanoparticle superlattices (BNSLs) composed of NaREF4 :Yb/Er (RE = Y and Gd) UCNPs and plasmonic metallic nanoparticles (Au NPs), including AB, AB3 , and AB13 lattices, are fabricated via a slow evaporation-driven self-assembly to achieve plasmonic modulation of upconversion luminescence (UCL). Optical measurements reveal that typical red-green UCL from UCNPs can be effectively modulated into reddish output in BNSLs, with a drastically shortened lifetime. Notably, for AB3 - and AB13 -type BNSLs with more proximal Au NPs around each UCNP, modified UCL with fine-structured spectral lineshape is observed. These differences could be interpreted by the interplay of collective plasmon resonance introduced by 2D periodic Au arrays and spectrally selective energy transfer between UCNPs and Au. Thus, fabricating UCNP-Au BNSLs with desired lattice parameters and NP configurations could be a promising way to tailor the UCL through controlled plasmonic modulation.

Electrochromism induced reversible upconversion luminescence modulation of WO3:Yb3+, Er3+ inverse opals for optical storage application

Reversible modulated upconversion luminescence exhibits an application potential as the photo-switch, fingerprint acquisition, anti-counterfeiting and optical storage devices. It is found that the photochromism and thermochromism could be applied to modify the upconversion luminescence. However, the electrochromism induced reversible upconversion luminescence modulation was not reported. Here, the WO3:Yb3+, Er3+ inverse opal was prepared by the template approach, and its electrochromism property was investigated. The color changing of WO3:Yb3+, Er3+ inverse opal from a bit yellow to black was observed upon the negative bias voltage stimulation, and its color can be recovered upon the positive bias voltage stimulation. For the first time, the electrochromism induced reversible upconversion luminescence modulation of WO3:Yb3+, Er3+ inverse opal was observed, exhibiting a high modulation degree (100%). In addition, the reversibly modulated upconversion luminescence exhibited excellent repeatability and stability by alternating stimulation between negative bias voltage and positive bias voltage. The present results open up a new channel to modulate the upconversion luminescence of materials, exhibiting the application potential in the switch, anti-counterfeiting and optical storage devices. As an instance, the application potential of WO3:Yb3+, Er3+ inverse opal was described as an optical storage medium, and the optical date writing and reading out were obtained in the electrochromic WO3:Yb3+, Er3+ inverse opal.

Efficient modulation of upconversion luminescence in NaErF4-based core–shell nanocrystals

Efficient modulation of upconversion luminescence in heavily-doped core–shell nanocrystals by the tuning of [F]/[RE] ratio during synthesis.

Upconversion Nanoparticles: Millisecond‐Timescale, High‐Efficiency Modulation of Upconversion Luminescence by Photochemically Derived Graphene (Advanced Optical Materials 24/2019)

Upconversion Nanoparticles: Millisecond‐Timescale, High‐Efficiency Modulation of Upconversion Luminescence by Photochemically Derived Graphene (Advanced Optical Materials 24/2019)

Millisecond‐Timescale, High‐Efficiency Modulation of Upconversion Luminescence by Photochemically Derived Graphene

AbstractThe millisecond‐timescale, high‐efficiency modulation of upconversion luminescence via ultraviolet laser‐induced photochemical reduction of graphene oxide is reported. The luminescence tuning is achieved by combining a thin film of graphene oxide with lanthanide‐doped upconversion nanoparticles. The recovery of the graphene‐like structure through the photochemical reduction of graphene oxide is accompanied by a variation in the absorption coefficient of the as‐synthesized nanocomposite, which enables super‐quenching of the luminescence emission from the upconversion nanoparticles under near‐infrared laser excitation with values of up to ≈90%. Further, the instantaneous reduction in the emission intensity upon ultraviolet laser irradiation allows a 106‐fold decrease of the time for fast modulation of upconversion luminescence from up to tens of minutes down to milliseconds at microwatt‐level laser power. Optical patterning is successfully produced in the nanocomposite and individual pixels are retrieved distinctly with high spatial resolution through upconversion luminescence emission quenching by reduced graphene oxide. This method offers a superior avenue for controlling upconversion luminescence with high contrast, fast reaction speed, and low power consumption.

Reversible Modulated Upconversion Luminescence of MoO3:Yb3+,Er3+ Thermochromic Phosphor for Switching Devices.

Reversible modulation of upconversion luminescence induced by the external field stimuli exhibits potential applications in various fields, such as photoswitches, optical sensing, and optical memory devices. Herein, a new MoO3:Yb3+,Er3+ thermochromic phosphor was synthesized via a high-temperature solid-state method, and the reversible color modification of the MoO3:Yb3+,Er3+ phosphor was obtained by alternating the sintering conditions either in a reducing atmosphere or in air. The color of the MoO3:Yb3+,Er3+ phosphor changed from light-yellow to blue under sintering in the reducing atmosphere and returned back after sintering again in air. The influence of reversible thermochromism on the upconversion luminescence of MoO3:Yb3+,Er3+ phosphor was investigated. The MoO3:Yb3+,Er3+ phosphor prepared in air exhibited visible upconversion luminescence, while the MoO3:Yb3+,Er3+ phosphor has no upconversion luminescence after sintering in the reducing atmosphere. This up-conversion luminescence modulation shows excellent reproducibility after several cycles. The thermochromic MoO3:Yb3+,Er3+ phosphor with reversible modulated upconversion luminescence shows great potential for practical applications in optical switches and optoelectronic multifunctional devices.

纳米金膜及金壳表面局域等离激元对上转换荧光波长的选择调控

纳米金膜及金壳表面局域等离激元对上转换荧光波长的选择调控

Phase transformation induced reversible modulation of upconversion luminescence of WO3:Yb3+, Er3+ phosphor for switching devices.

The upconverting luminescence properties of phosphors are dependent on the hosts. In this work, the WO3:Yb3+, Er3+ phosphor was prepared, and the reversible phase transformation from the WO3 to the WO2 was obtained by alternating the sintering in a reducing atmosphere or in air. The influence of reversible phase transformation on the upconversion luminescence was investigated first. The WO3:Yb3+, Er3+ phosphor exhibits the visible upconversion luminescence, while no upconversion luminescence was observed in the WO2:Yb3+, Er3+ phosphor. The reversible modulation of upconversion luminescence of the WO3:Yb3+, Er3+ phosphor retains the excellent reproducibility, exhibiting the potential applications in data storage and optical switches.

Host lattice manipulation-induced upconversion luminescence modulation through diatomic metal ions intervening

Host lattice manipulation-induced upconversion luminescence modulation through diatomic metal ions intervening

The upconversion luminescence modulation and its enhancement in Er3+‐doped Na0.5Bi0.5TiO3 based on photochromic reaction

AbstractA large and reversible upconversion (UC) luminescence modulation has been found in the Na0.498Bi0.498TiO3:0.002Er (NBT:0.002Er) based on the photochromic reaction. The dependence of luminescence modulation of the ceramics on the wavelength of irradiation light and sintering temperature was investigated. It was found that the optimized sintering temperature and irradiation wavelength were 1130°C and 405 nm, respectively. The highest ΔRt (defined as: ΔRt = (R0 – Rt)/R0×100(%), where R0 and Rt are the initial emission intensity and that after different irradiation time, respectively) value of 44.9% was obtained for the ceramics sintered at 1130°C after irradiation at 405 nm. More importantly, for the poled ceramics, ΔRt value was promoted to a high value of 75.5%, which was 168% of that of the unpoled ones. The mechanism of luminescence modulation and its enhancement via electric field poling were discussed. This study demonstrated that electric field poling was an effective strategy to enhance the PC reaction in the NBT ceramics.

Thermomchromic Reaction-Induced Reversible Upconversion Emission Modulation for Switching Devices and Tunable Upconversion Emission Based on Defect Engineering of WO3:Yb3+,Er3+ Phosphor.

Reversible luminescence modulation of upconversion phosphors has the potential applications as photoswitches and optical memory and data storage devices. Previously, the photochromic reaction was extensively used for the realization of reversible luminescence modulation. It is very necessary to develop other approaches such as thermomchromic reaction to obtain the reversible upconversion luminescence modulation. In this work, the WO3:Yb3+,Er3+ phosphors with various colors were prepared at various temperatures, exhibiting tunable upconversion luminescence attributed to the formation of oxygen vacancies in the host. Upon heat treatment in the reducing atmosphere or air, the WO3:Yb3+,Er3+ phosphors show a reversible thermomchromic property. The reversible upconversion luminescence modulation of WO3:Yb3+,Er3+ phosphors was observed based on thermomchromic reaction. Additionally, the upconversion luminescence modulation is maintained after several cycles, indicating its excellent stability. The WO3:Yb3+,Er3+ phosphors with reversible upconversion luminescence and excellent reproducibility have potential applications as the photoswitches and optical memory and data storage devices.

Remote manipulation of upconversion luminescence.

The precise control over the luminescence profile of lanthanide-doped upconversion nanomaterials is of fundamental importance for their applications in wide-ranging fields of research. Conventional chemical approaches can lead to color-tunable emissions, but they generally require stringent modification either on dopant composition or doping concentration. In this Tutorial Review, we highlight a number of complementary methods that offer remote dynamic modulation of upconversion luminescence across the visible spectrum. This review serves to provide a summary of existing guidelines for controlling the emission spectrum of upconversion nanocrystals with fixed materials composition. The review will also discuss the major approaches to manipulating excitation energies and consider likely research challenges for further development of the field at the interface between nanotechnology and biological science.

Sc3+-induced morphology, phase structure, and upconversion luminescence evolution of YF3:Yb/Er nanocrystals

The comprehensive studies of Sc3+-induced morphology, phase structure, and upconversion luminescence modulation of YF3:Yb/Er nanocrystals have been reported.

Chromaticity modulation of upconversion luminescence in CaSnO3:Yb3+, Er3+, Li+ phosphors through Yb3+ concentration, pumping power and temperature

CaSnO3:Yb3+, Er3+, Li+ upconverting phosphors are synthesized by a simple solid state method. The doping concentration of Li+ ions is optimized by comparatively studying upconversion luminescence of samples with various Li+ content. The effects of Yb3+ concentration, pumping power and temperature on chromaticity of upconversion luminescence in CaSnO3:Yb3+, Er3+, Li+ phosphors are investigated, the related mechanisms are discussed and the abilities to modulate chromaticity are evaluated.