near-UV Excitation Research Articles

Fluorescent porous silicon biological probes with high quantum efficiency and stability.

We demonstrate porous silicon biological probes as a stable and non-toxic alternative to organic dyes or cadmium-containing quantum dots for imaging and sensing applications. The fluorescent silicon quantum dots which are embedded on the porous silicon surface are passivated with carboxyl-terminated ligands through stable Si-C covalent bonds. The porous silicon bio-probes have shown photoluminescence quantum yield around 50% under near-UV excitation, with high photochemical and thermal stability. The bio-probes can be efficiently conjugated with antibodies, which is confirmed by a standard enzyme-linked immunosorbent assay (ELISA) method.

Preparation of Sr8Mg1−mZnmY(PO4)7:Eu2+solid solutions and their luminescence properties

A series of orthophosphate solid solutions with a general formula of Sr8Mg1−mZnmY(PO4)7: Eu2+ (0 ≤ m ≤ 1) were synthesized by the combustion-assisted synthesis technique. The XRD patterns confirm the formation of a solid solution of Sr8Mg1−mZnmY(PO4)7 and lattice parameters of the solid solutions are linearly dependent on m. The excitation spectra of these phosphors show broad band excitation and absorption in the 250–470 nm near ultraviolet (UV) region, which is ascribed to the 4f7–4f65d1 transitions of Eu2+. With an increase in m, the emission color shifts from yellow to green under near-UV excitation, which is rationalized in terms of two competing factors of the crystal filed strength and bond covalence. All the results indicate that the solid solution Sr8Mg1−mZnmY(PO4)7: Eu2+ can be a good candidate of phosphor applicable to near-UV LEDs for solid-state lighting.

Fragmentation mechanism of UV-excited peptides in the gas phase.

We present evidence that following near-UV excitation, protonated tyrosine- or phenylalanine-containing peptides undergo intersystem crossing to produce a triplet species. This pathway competes with direct dissociation from the excited electronic state and with dissociation from the electronic ground state subsequent to internal conversion. We employ UV-IR double-resonance photofragment spectroscopy to record conformer-specific vibrational spectra of cold peptides pre-excited to their S1 electronic state. The absorption of tunable IR light by these electronically excited peptides leads to a drastic increase in fragmentation, selectively enhancing the loss of neutral phenylalanine or tyrosine side-chain, which are not the lowest dissociation channels in the ground electronic state. The recorded IR spectra evolve upon increasing the time delay between the UV and IR pulses, reflecting the dynamics of the intersystem crossing on a timescale of ~80 ns and <10 ns for phenylalanine- and tyrosine-containing peptides, respectively. Once in the triplet state, phenylalanine-containing peptides may live for more than 100 ms, unless they absorb IR photons and undergo dissociation by the loss of an aromatic side-chain. We discuss the mechanism of this fragmentation channel and its possible implications for photofragment spectroscopy and peptide photostability.

The pure-phase Ba3−xCaxSi6O12N2:Eu2+green phosphor: synthesis, photoluminescence and thermal properties

The promising green oxynitride phosphor, Ba3−xCaxSi6O12N2:Eu2+, was synthesized at 1350 °C for 5 hours under a reducing N2/H2 (5%) atmosphere via the solid-state reaction method. The XRD patterns confirm the formation of the pure phase of Ba3−xCaxSi6O12N2:Eu2+. With an increase in x, the emission spectra shift from 525 nm to 536 nm under near-UV (n-UV) excitation. Accordingly, we propose the underlying mechanisms for the red-shift of the emission spectra by adjusting the cation composition in the host. The influence of the size mismatch on the thermal quenching is also observed. The as-prepared green phosphor exhibits great thermal quenching property, with the remaining 83% of the initial emission intensity measured at 150 °C. The quantum efficiency is measured to be 35.2%. All the results indicate that the Ba3−xCaxSi6O12N2:Eu2+ can be a good candidate phosphor applicable to n-UV light-emitting diodes for solid-state lighting.

Crystal structure, electronic structure, and photoluminescence properties of La₃BW(1-x)Mo(x)O₉:Eu³⁺ red phosphor.

A series of La3BW(1-x)Mo(x)O9:Eu(3+) (x = 0-0.4) polycrystalline powders were prepared by using solid-state reactions. The phase structure, UV-vis absorption spectra, and photoluminescence properties were studied as a function of the Mo/W ratio. When Mo(6+) ions are incorporated into the lattice, the characteristic sharp lines in the excitation spectra of Eu(3+) monitored at 617 nm are prominently enhanced, which join the ligand-to-metal charge transfer (LMCT) band of La3BW(1-x)Mo(x)O9:Eu(3+) into a broad band ranging from 250 to 450 nm centered at 375 nm. The intensity of the broad excitation band reaches a maximum when the content of Mo(6+) ions increases to x = 0.3. On the other hand, the LMCT band around 306 nm decreases and shifts toward the longer wavelength. These features are advantageous to near-UV or blue light GaN-based LED applications. Orbital population analysis by density functional theory calculation (DFT) reveals that the near-UV excitation of La3BW(1-x)Mo(x)O9:Eu(3+) red phosphor is due to the electronic transition from the O 2p orbital to the W 5d and Mo 4d orbitals, respectively. With the introduction of Mo(6+) into the lattice, the band gap of La3BW(1-x)Mo(x)O9 becomes narrower than that of the pure phase La3BWO9.

Influence of Structural Polymorphs on Tunable White Light Generation from Orange-Red-Emitting BiPO4:Eu3+ Phosphor by Surface Modification

We report the surface modification of orange-red-emitting hexagonal and monoclinic polymorphs of BiPO4:Eu3+ with oleic acid (OA) for white light generation. The surface-modified hexagonal phase emits white light under near-UV excitation (350–395 nm) through the mixing of broad blue emission from OA and orange-red emission from Eu3+, whereas the same was not observed with the monoclinic phase. The variation in OA emission upon anchoring over the surface of hexagonal BiPO4:Eu3+ resulted in white light generation. Such variation in the interaction of OA with surfaces of BiPO4 polymorphs and surface induced midgap states was established through first-principles calculations that revealed the strong interaction of OA with hexagonal phase. The deduced density of states corroborates the experimental findings on the polymorph-dependent PL properties of OA-modified hexagonal and monoclinic BiPO4:Eu3+.

Growth and Structural Analysis of Silicate Phosphor Single Crystal Using Gas Phase Method

Silicate materials have been usually used as host materials of phosphors for white LEDs because there are high chemical stabilities, low cost and these silicate phosphors show good luminescence properties under near-UV and blue light excitation. In the series of silicate phosphors, orthosilicate phosphors, Ba-rich (Ba,Sr)2SiO4:Eu2+ (green emission) and Sr-rich (Ba,Sr)2SiO4:Eu2+ (yellow emission), have been used in white LEDs based blue light LED as commercial phosphors [1]. In addition, (Ca,Sr)2SiO4:Eu2+ phosphor are recently reported by M. Kakihana's which is shown the red emission by blue light excitation when larger amount of Eu2+ doped into the host lattice [2]. However, there are no reported on crystal structure data of alkaline earth silicate phosphors by single crystal structure analysis and the doping site of Eu2+in the host lattice also has not yet been established definitely. In this study, we prepared orthosilicate phosphor single crystals and the detail crystal data of these phosphors are gained by single-crystal structure analysis. The single crystal of orthosilicate phosphor are grew by a novel vapor phase technique (gas and solid phase hybrid synthesis method), which is gas (SiO) and solid phase (Ba/Sr/Ca/Eu compound) hybridized [3].Figure 1 shows the polarized microscope image of the Ba1.00(Sr0.77Eu0.23)SiO4 and the Ca0.116Sr1.810Eu0.074SiO4 phosphors single crystal under UV light (365 nm). Single crystal of Ba1.00(Sr0.77Eu0.23)SiO4 and Ca0.116Sr1.810Eu0.074SiO4 is plate-like crystal and the single crystal sizes of these phosphors are about 250 μm and 120 μm, respectively. These crystals used for structure analysis to investigate the doping site of Eu2+in the host lattice.Figure 2 shows the crystal structure of Ba1.00(Sr0.77Eu0.23)SiO4 phosphor single crystal obtained by X‐ray single-crystal diffraction analysis. The Ba1.00(Sr0.77Eu0.23)SiO4 phosphor has a orthorhomic structure and the space group of Pnma (No. 62) with the lattice parameters a = 0.73856 (12) nm, b = 0.57579 (9) nm, and c = 0.99394 (16) nm. Ba2+ is coordinated by 10 oxide anions and Sr2+ is coordinated by 9 oxide anions in Ba1.00(Sr0.77Eu0.23)SiO4 crystal structure. Furthermore, Eu2+ is only substituted into the Sr2+ site because the ionic radius of Sr2+ (0.131 nm; CN = 9) and Eu2+ (0.130 nm; CN = 9) are nearly length while the ionic radius of Sr2+ is much smaller than that of the Ba2+(0.152 nm; CN = 10) [4].Figure 3 shows the crystal structure of Ca0.116Sr1.810Eu0.074SiO4 phosphor single crystal obtained by X‐ray single-crystal diffraction analysis. The Ca0.116Sr1.810Eu0.074SiO4 phosphor also has a orthorhomic structure and the space group of Pnma (No. 62) with the lattice parameters a = 0.70548 (11) nm, b = 0.56524 (8) nm, and c = 0.96805 (14) nm. Sr2+ is coordinated by 10 and 9 oxide anions in Ca0.116Sr1.810Eu0.074SiO4 crystal structure and small amount of Ca2+ is coordinated by 9 oxide anions. Moreover, Eu2+ is only substituted into the 10 coordination site of Sr2+ in the Ca0.116Sr1.810Eu0.074SiO4 phosphor, which is different from Ba1.00(Sr0.77Eu0.23)SiO4 phosphor. Since ionic radius of Ca2+ (0.118 nm; CN = 9) is smaller than Eu2+, Ca2+ is preferentially substituted into the 9 coordination site of Sr2+ in the case of Ca0.116Sr1.810Eu0.074SiO4 phosphor. To the best of our knowledge, this is the report of the crystal structure of single crystal of orthosilicate phosphors and the definite doping site of Eu2+in the orthosilicate phosphors lattice.

Cold white light generation through the simultaneous emission from Ce3+ and Tb3+ in sodium germanate glass

A spectroscopic investigation of sodium germanate glasses activated with Ce3+, Tb3+ and Ce3+/Tb3+ is carried out by analyzing their photoluminescence spectra and decay times. Non-radiative energy transfer from Ce3+ to Tb3+ is observed upon near-UV excitation at 310nm (peak emission wavelength of AlGaN-based LEDs). The non-radiative nature of this energy transfer is inferred from the increase in the decay rate of the Ce3+ emission when the glass is co-doped with Tb3+. From an analysis of the Ce3+ emission decay time curve it is inferred that an electric dipole–quadrupole interaction might to be the dominant mechanism for the Tb3+ emission sensitized by Ce3+. Energy transfer from Ce3+ to Tb3+ leads to a simultaneous emission of these ions in the blue, green, yellow and red, resulting in white light with CIE1931 chromaticity coordinates, x=0.30 and y=0.32, which correspond to cold white light with a colour temperature of 7320K and very small deviation from the Planckian black-body radiator locus (0.005).

X-ray analysis and optical studies of Dy3+ doped NaSrB5O9 microstructures for white light generation

A white light emitting phosphor NaSrB5O9:Dy3+ was synthesized by a conventional solid state reaction method. The structure of the phosphors was analyzed by powder X-ray diffraction (XRD), revealing that the phosphors crystallized in monoclinic crystal structure with the space group (P21/c). Williamson–Hall (W–H) analysis was used to study the individual contributions of crystallite sizes and lattice strain on the peak broadening of NaSrB5O9:Dy3+ phosphors. Monoclinic microstructures of nearly plate-like morphologies were observed in the FE-SEM images. Upon near-UV excitation wavelength (390nm), the blue emission at ∼482nm (6H15/2) and yellow emission at ∼584nm (6H13/2) were observed in the phosphors. The critical quenching concentration of Dy3+ in NaSrB5O9 phosphor was found to be 3 at.% with the critical distance (Rc) of ∼22.30Å and the corresponding concentration quenching mechanism was testified to be the exchange interaction between the dopant Dy3+ ions. In order to investigate the application in white LEDs, the Commission International de l’Eclairage (CIE) chromaticity coordinates, color temperature and decay curve measurements of Dy3+ ions doped NaSrB5O9 phosphors were carried out. The yellow to blue (Y/B) emission integrated intensity ratio is maximum (∼0.9) for all the concentrations, suggesting that the phosphors favor for white illumination.

Effects of Annealing on the Photoluminescence Properties of Citrate-Capped YVO4:Bi3+,Eu3+ Nanophosphor

We investigated the effects of annealing on the photoluminescence (PL) properties of a citrate-capped YVO4:Bi3+,Eu3+ nanophosphor. The 300 °C annealed nanophosphor exhibited the highest PL intensity at 619.5 nm corresponding to an f–f transition of Eu3+ under near-UV excitation. Fourier transform infrared spectroscopy indicated a decrease in the amounts of adsorbed water and citrate on the nanophosphor surface with annealing. Dehydration and the increase in near-UV absorption contributed to the improved PL intensity, since water is a Eu3+ luminescence quencher. The thermal decomposition of citrate, which photoreduces vanadate under near-UV irradiation, caused the improved photostability. Annealing at ≥400 °C decreased the PL intensity. A color change from white to yellow may be attributed to absorption by byproducts, possibly formed by the segregation of YVO4:Bi3+,Eu3+. A shorter PL lifetime and lower activation energy of thermal quenching at higher annealing temperature were confirmed from PL decay curve...

Combustion Synthesis and Optical Properties of Eu3+-Doped BaGd2ZnO5 f–f Transition Nanophosphor for White LED

An Eu3+-doped BaGd2(1−x)ZnO5 nanophosphor has been synthesized by means of a single-step, urea-assisted, solution-combustion process. The structural, morphological, and optical properties of the nanophosphor were studied by x-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The XRD results showed that the pure orthorhombic BaGd2ZnO5 structure with space group Pbnm was obtained at 900°C. The intense red luminescence at 628 nm on near-UV (396 nm) excitation is because of the hypersensitive 5D0 → 7F2 transition of luminescent activator Eu3+ ions, located at a site with no inversion symmetry in the BaGd2ZnO5 crystal lattice. The optimum doping concentration and decay time of Eu3+-doped BaGd2(1−x)ZnO5 nanophosphor were also determined. The emission could be effectively tuned from blue to the white and red regions by varying the concentration of europium ions. Decay curve analysis revealed that cross-relaxation is primarily responsible for the concentration quenching. High luminescent intensity, low-cost, easy synthesis, uniform shape, and controlled color tunability suggest use of BaGd2ZnO5:Eu3+ as an efficient red-emitting nanophosphor for near-UV-based LED solid-state lighting applications.

Anomalous luminescence from Yb2+-doped Ca2PO4Cl

The photoluminescence of Ca2PO4Cl:Yb2+ has been investigated and compared with that of Ca2PO4Cl:Eu2+, and the application of Ca2PO4Cl:Yb2+ for white LED has been evaluated. The excitation spectra of Ca2PO4Cl:Yb2+ are dominated by an intense excitation band at 395nm. Under near-UV excitation at 395nm, Ca2PO4Cl:Yb2+ shows a broad asymmetric emission with maximum at 490nm. This emissions result from two different Yb2+ centers is evidenced by the low temperature (T=100K) emission spectrum. Yb2+ luminescence differs significantly from that of Eu2+, most notably in the structure of emission spectra, and is characterized by a much broader emission band and lower quenching temperature. Such anomalous luminescence from Yb2+ is ascribed to the de-excitation process of the Yb2+-trapped exciton state. Ca2PO4Cl:Yb2+ has external quantum efficiency of 24% and exhibits 40% of luminescence quenching at 100°C in the air and, therefore, these results reveal its limited potential in the fabrication of white-light LEDs.

Hydrothermal syntheses and photoluminescence properties of rare-earth tungstate as near ultraviolet type red phosphors

Three families of scheelite CaWO4-based red luminescent phosphors, Ca1−1.5xWO4:xEu3+ (0.02 ≤ x ≤ 0.09), Ca0.925−ySryWO4:0.05Eu3+ (0 ≤ y ≤ 0.9) and Ca0.625Sr0.30W1−zMozO4:0.05Eu3+ (0 ≤ z ≤ 0.7) were hydrothermally prepared and characterized. The substitutions of Sr2+ for Ca2+ and Mo6+ for W6+, which improve local symmetries surrounding Eu3+, assisted the energy transfer from O2− to Eu3+ in the process of optimizing the luminescence properties. The z = 0.2 members of Ca0.625Sr0.30W0.80Mo0.20O4:0.05Eu3+ exhibited excellent bright red luminescence at 616 nm under near-UV excitation, narrowed emission spectra, room temperature luminescence lifetimes of milliseconds and maximum quantum efficiencies of 49%.

Glycothermal synthesis and photoluminescent properties of Ce3+-doped YBO3 mesocrystals

Abstract We report a glycothermal synthesis of Ce 3+ -doped YBO 3 mesocrystals and their Ce 3+ -concentration dependence of particulate and photoluminescent properties. Submicrometer-sized YBO 3 :Ce 3+ disk-like particles with Ce 3+ concentrations of 0–3 at.% were formed from trimethyl borate and acetates of yttrium and cerium(III) via a glycothermal reaction at 300 °C for 2 h in 1,4-butanediol. The size of the particles decreased from ∼1.5 μm to ∼150 nm with increasing the Ce 3+ concentration up to 1 at.%. Selected area electron diffraction revealed that each disk-like particle was a mesocrystal, i.e., an assembly of nanocrystals with a uniform crystallographic orientation, irrespective of the Ce 3+ concentration. The particles showed blue emission through 5d–4f transitions of Ce 3+ under near-UV excitation. Concentration quenching of the Ce 3+ emission for the glycothermally-prepared YBO 3 :Ce 3+ started from a lower Ce 3+ concentration than that of solid-state-prepared bulk YBO 3 :Ce 3+ , indicating an inhomogeneous distribution of Ce 3+ ions in the mesocrystals.

Tryptophan-accelerated electron flow across a protein-protein interface.

We report a new metallolabeled blue copper protein, Re126W122Cu(I) Pseudomonas aeruginosa azurin, which has three redox sites at well-defined distances in the protein fold: Re(I)(CO)3(4,7-dimethyl-1,10-phenanthroline) covalently bound at H126, a Cu center, and an indole side chain W122 situated between the Re and Cu sites (Re-W122(indole) = 13.1 Å, dmp-W122(indole) = 10.0 Å, Re-Cu = 25.6 Å). Near-UV excitation of the Re chromophore leads to prompt Cu(I) oxidation (<50 ns), followed by slow back ET to regenerate Cu(I) and ground-state Re(I) with biexponential kinetics, 220 ns and 6 μs. From spectroscopic measurements of kinetics and relative ET yields at different concentrations, it is likely that the photoinduced ET reactions occur in protein dimers, (Re126W122Cu(I))2 and that the forward ET is accelerated by intermolecular electron hopping through the interfacial tryptophan: *Re//←W122←Cu(I), where // denotes a protein-protein interface. Solution mass spectrometry confirms a broad oligomer distribution with prevalent monomers and dimers, and the crystal structure of the Cu(II) form shows two Re126W122Cu(II) molecules oriented such that redox cofactors Re(dmp) and W122-indole on different protein molecules are located at the interface at much shorter intermolecular distances (Re-W122(indole) = 6.9 Å, dmp-W122(indole) = 3.5 Å, and Re-Cu = 14.0 Å) than within single protein folds. Whereas forward ET is accelerated by hopping through W122, BET is retarded by a space jump at the interface that lacks specific interactions or water molecules. These findings on interfacial electron hopping in (Re126W122Cu(I))2 shed new light on optimal redox-unit placements required for functional long-range charge separation in protein complexes.

Wide-Band Excited Y6(WMo)0.5O12:Eu Red Phosphor for White Light Emitting Diode: Structure Evolution, Photoluminescence Properties, and Energy Transfer Mechanisms Involved

Y6(WMo)(0.5)O12 activated with Eu(3+) ions was investigated as a red-emitting conversion phosphor for white light emitting diodes (WLEDs). The phosphors were synthesized by calcining a citrate-complexation precursor at different temperatures. The photoluminescence properties of the phosphors and the energy transfer mechanisms involved were studied as a function of structure evolution. It was found that the host lattices were crystallized in a cubic or a hexagonal phase depending on the synthesis conditions. Although all the phosphors showed intensive red emission under an excitation of near-UV or blue light due to energy transfer from the host lattices to Eu(3+) ions, the photoluminescence spectra and temporal decay features were found to vary significantly with the structure and crystallinity of the host lattice. The mechanisms of the energy transfer from the host lattices to Eu(3+) ions and energy quenching among Eu(3+) ions were discussed on the basis of structure evolution of the host lattice. Phosphors calcined at 800 and 1300 °C were suggested to be promising candidates for blue and near-UV light excited WLEDs, respectively.

Photophysics of polymeric carbon nitride: An optical quasimonomer

A comprehensive investigation of the luminescent properties of carbon nitride polymers, based on tri-$s$-triazine units, has been conducted. Steady-state temperature- and excitation-power-dependent as well as time-resolved measurements with near-UV excitation ($\ensuremath{\lambda}=325$ nm and 405 nm) yield strong photoluminescence, covering the visible spectrum. The spectral, thermal, and temporal features of the photoluminescence can be satisfactorily described by the excitation and radiative recombination of molecular excitons, localized at single tri-$s$-triazine units. The discussed model is in accordance with the recently reported absorption features of carbon nitride polymers. Thus, from the point of view of optical spectroscopy, the material effectively behaves as a monomer.

Emission Color Variation of Sr&lt;sub&gt;3&lt;/sub&gt;SiO&lt;sub&gt;5&lt;/sub&gt;:Ce&lt;sup&gt;3+&lt;/sup&gt;, Li&lt;sup&gt;+&lt;/sup&gt; Phosphor for Near-UV Light-Emitting Diodes by Co-Doping with Mg&lt;sup&gt;2+&lt;/sup&gt; and Ba&lt;sup&gt;2+&lt;/sup&gt;

This paper reports the spectral variation of Sr3SiO5: Ce3+, Li+ phosphor. It was synthesized by the conventional solid state method. The effects of calcining temperature and codoption of Mg2+ and Ba2+ on phase composition, structure, photoluminescence and thermal stability were firstly investigated in detail. Under the near-UV excitation of 415 nm, Sr3SiO5: Ce3+, Li+ emits a bright greenish-yellow color centered at 532nm, which originates from 5d to 4f (2F7/2 and 2F5/2) transition of Ce3+. The PL spectra show the different emission color variation with substituting Sr2+ cations with smaller Mg2+ or larger Ba2+, which makes it be applied as a color-tunable phosphor for LED based on near-UV chip/phosphor technology. Simultaneously, the thermal stability of (Sr,Ba)3SiO5: Ce3+, Li+ phosphor is improved markedly.

A structural approach of the flux effect on blue phosphor BAM:Eu (BaMgAl10O17:Eu2+)

In the aim of understanding the relations between the spectroscopic properties of blue phosphor BaMgAl10O17:Eu2+ and its crystal structure, microstructure and chemical composition, three fluoride fluxes (LiF, MgF2 and NH4F) have been added before final thermal treatment and their effect analyzed. LiF changes the polycrystalline and spherical grains into hexagonal platelets without significant cations exchange and improves the luminescence. NH4F and MgF2 only have a limited effect, the former because of its low point of decomposition, the latter because of the formation of spurious MgAl2O4 that reduces the luminescence. In a general way, re-crystallization results in variations of the dopant distribution between the three host sites of the structure. Chromaticity is only faintly affected, but important variations of the absorption and excitation spectra are observed, allowing a strong increase of photoluminescence intensity under near-UV excitation.

Lanthanide-doped ceria nanoparticles as fluorescence-quenching probes for dissolved oxygen

This paper investigates a novel usage of lanthanide-doped ceria nanoparticles (LDC-NPs) to sense dissolved oxygen (DO) in aqueous media via quenching of the fluorescence emission. The lanthanide dopants selected for this study are samarium and neodymium, which have been shown to increase the concentration and mobility of oxygen vacancies in ceria. The amplitude of the visible emission, resulting from near-UV excitation at room temperature, is found to decrease with increasing DO concentration. As an indicator of the sensitivity to DO concentration, the Stern–Volmer constants (KSV) of the LDC-NPs are found to be larger than KSV for undoped ceria and for other polymer fluorescent dyes currently used to sense DO. The stability of KSV with respect to temperature (20–50°C) is studied for each of the LDC-NPs. The Stern–Volmer constants of the LDC-NPs are significantly less temperature dependent as compared to the temperature dependence of KSV in commercially-available DO molecular probes. The results of this study can potentially advance the development of DO sensors for biomedical, industrial, and environmental applications.