Changes In Emission Intensity Research Articles

Triple-temperature readout in luminescence thermometry with Cr3+-doped Mg2SiO4 operating from cryogenic to physiologically relevant temperatures

Cr3+-doped Mg2SiO4 orthorhombic nanoparticles are synthesized by a combustion method. The 3d3 electron configuration of the Cr3+ ion results in the deep-red emission from optical transitions between d–d orbitals. Two overlapping emissions from the Cr3+ spin-forbidden 2Eg→ 4A2g and the spin-allowed 4T2g→ 4A2g electronic transitions are influenced by the strong crystal field in Mg2SiO4 and, thus, are suitable for ratiometric luminescence thermometry. The temperature-induced changes in Cr3+-doped Mg2SiO4 emission are tested for use in luminescence thermometry from cryogenic to physiologically relevant temperatures (10–350 K) by three approaches: (a) temperature-induced changes of emission intensity; (b) temperature-dependent luminescence lifetime; and (c) temperature-induced changes of emission band position. The second approach offers applicable thermometry at cryogenic temperatures, starting from temperatures as low as 50 K, while all three approaches offer applicable thermometry at physiologically relevant temperatures with relative sensitivities of 0.7% K−1 for emission intensity, 0.8% K−1 for lifetime and 0.85% K−1 for band position at 310 K.

Source emissions and climate change impacts on the multimedia transport and fate of persistent organic pollutants, Chaohu watershed, eastern China

Emission intensity and climate change control the transport flux and fate of persistent organic pollutants (POPs) in multiple environmental compartments. This study applied a multimedia model (BETR model) to explore alternations in the spatio-temporal trends of concentrations and transport flux of benzopyrene (BaP), phenanthrene (Phe), perfluorooctane sulfonates (PFOS) and polychlorinated biphenyls (PCBs) in the Chaohu watershed, located in the lower reaches of the Yangtze River, China in response to changes in source emissions and climate. The potential historic and future risks of these pollutants also were assessed. The results suggest that current trends in concentrations and transport were similar to that of their emissions between 2005 and 2018. During the next 100 years, temporal trends and spatial patterns were not predicted to change significantly, which is consistent with climate change. Based on sensitivity and correlation analyses, climate change had significant effects on multi-media concentrations and transport fluxes of BaP, Phe, PFOS and PCBs, and rainfall intensity was the predominant controlling factor. Risk quotients (RQs) of BaP and Phe-in soil increased from 0.42 to 0.95 and 0.06 to 0.35, respectively, from 2005 to 2090, indicating potential risks. The RQs of the other examined contaminants exhibited little potential risk in soil, water, or sediment. Based on spatial patterns, it was inferred that the ecosystem around Lake Chaohu is the most at risk. The study provides insights needed for local pollution control of POPs in the Chaohu watershed. In addition, the developed approach can be applied to other watersheds world-wide.

Effect of Oxygen Mole Fraction on Static Properties of Pressure-Sensitive Paint.

The effects of the oxygen mole fraction on the static properties of pressure-sensitive paint (PSP) were investigated. Sample coupon tests using a calibration chamber were conducted for poly(hexafluoroisopropyl methacrylate)-based PSP (PHFIPM-PSP), polymer/ceramic PSP (PC-PSP), and anodized aluminum PSP (AA-PSP). The oxygen mole fraction was set to 0.1–100%, and the ambient pressure () was set to 0.5–140 kPa. Localized Stern–Volmer coefficient increased and then decreased with increasing oxygen mole fraction. Although depends on both ambient pressure and the oxygen mole fraction, its effect can be characterized as a function of the partial pressure of oxygen. For AA-PSP and PHFIPM-PSP, which are low-pressure- and relatively low-pressure-type PSPs, respectively, peaks at kPa. In contrast, for PC-PSP, which is an atmospheric-pressure-type PSP in the investigated range, does not have a peak. has a peak at a relatively high partial pressure of oxygen due to the oxygen permeability of the polymer used in the binder. The peak of , which is the emission intensity change with respect to normalized pressure fluctuation, appears at a lower partial pressure of oxygen than that of . This is because the intensity of PSP becomes quite low at a high partial pressure of oxygen even if is high. Hence, the optimal oxygen mole fraction depends on the type of PSP and the ambient pressure range of the experiment. This optimal value can be found on the basis of the partial pressure of oxygen.

Multifunctionality in Polymer Networks by Dynamic of Coordination Bonds

AbstractThe need for multifunctional materials is driven by emerging technologies and innovations, such as in the field of soft robotics and tactile or haptic systems, where minimizing the number of operational components is not only desirable, but can also be essential for realizing such devices. This study report on designing a multifunctional soft polymer material that can address a number of operating requirements such as solvent resistance, reshaping ability, self‐healing capability, fluorescence stimuli‐responsivity, and anisotropic structural functions. The numerous functional abilities are associated to rhodium(I)–phosphine coordination bonds, which in a polymer network act with their dynamic and non‐covalently bonded nature as multifunctional crosslinks. Reversible aggregation of coordination bonds leads to changes in fluorescence emission intensity that responds to chemical or mechanical stimuli. The fast dynamics and diffusion of rhodium–phosphine ions across and through contacting areas of the material provide for reshaping and self‐healing abilities that can be further exploited for assembly of multiple pieces into complex forms, all without any loss to material‐sensing capabilities.

A unique self-reporting photosensitizer enabling simultaneous photodynamic therapy and real-time monitoring of phototheranostic process in a dynamic dual-color mode.

Phototheranostics has attracted great interest in cancer therapy. Small-molecule self-reporting photosensitizers, one kind of idea agent in phototheranostics, enables simultaneous photodynamic therapy (PDT) and feedback of therapeutic efficacy. However, previous such photosensitizers exclusively employed the change of single emission to monitor cell death, which can be disturbed by variations in photosensitizer concentration and the excitation intensity. Herein, we report a unique self-reporting photosensitizer TPA-3PyA+ constructed from a twisted triphenylamine unit (TPA), three benzene ring units and three cyanovinyl-pyridinium units (PyA) for PDT and its real-time monitoring in a dynamic dual-color mode. TPA-3PyA+ possesses a rotatable electron donor-π bridge-electron acceptor framework and exhibits high singlet oxygen quantum yield (124%) and a twisted intramolecular charge transfer (TICT) effect. TPA-3PyA+ not only enables effective staining of cancer cells with dual-color fluorescence due to the TICT effect but also shows excellent PDT performance. The simultaneous change in emission color, intensity and intracellular location of TPA-3PyA+ during cell death allows it to self-report cell death. Moreover, the change of dual-emission color allows distinguishing living and dead cells and effectively avoids interference in previous single-emission self-reporting photosensitizers. This work highlights the great potential of a self-reporting photosensitizer with dual-color emissions for efficient feedback of theranostics.

Enhanced Terahertz Radiation by Efficient Spin-to-Charge Conversion in Rashba-Mediated Dirac Surface States.

The enhancement of terahertz (THz) radiation is of extreme significance for the realization of the THz probe and imaging. However, present THz technologies are far from being enough to realize high-performance and room-temperature THz sources. Fortunately, topological insulators (TIs), with spin-momentum-locked Dirac surface states, are expected to exhibit a high terahertz emission efficiency. In this work, the novel concept of a Rashba-state-enhanced spintronic THz emitter is demonstrated on the basis of ferromagnet/heavy metal/topological insulator (FM/HM/TI) heterostructure. We find that the THz emission intensity changes as a function of HM interlayer thickness, and a 1.98 times higher intensity compared to that of FM/TI can be achieved when a meticulously designed thickness of the HM layer is inserted. The improvement of terahertz radiation is ascribed to the additive effect of Rashba splitting and topological surface states at the HM/TI interface. These results offer new possibilities for realizing spintronic THz emitters in TI-based magnetic heterostructures.

Detection of amine gases by inverse opal photonic crystals infiltrated with precursor HPQ‐Ac of aggregation‐induced emission luminogen

AbstractIn this study, to detect amine gases such as ammonia, a kind of biological gas, with high sensitivity, we fabricated a device that combines an inverse opal photonic crystal (IOPC) and 2‐(4‐oxo‐3,4‐dihydroquinazolin‐2‐yl)phenyl acetate (HPQ‐Ac), a precursor of the aggregation‐induced emission luminogen. IOPC silica structures (200IOPC, 350IOPC, 500IOPC) with SiO2 were respectively obtained after calcination with 200, 350, and 500 nm polystyrene (PS) nanoparticles used as templates and tetraethyl orthosilicate (TEOS) formed by self‐assembly on a slide glass. Furthermore, mesopore‐introduced IOPC (50 nm‐350IOPC) was prepared by mixing 350 and 50 nm PS particles in TEOS solution. Each IOPC was infiltrated with HPQ‐Ac, reacted with ammonia, and the rate of change in emission intensity owing to fluorescence was examined. The highest response was obtained for 350IOPC infiltrated with HPQ‐Ac among the three IOPCs without mesopores. The 50 nm‐350IOPC had higher sensitivity than 350IOPC and was found to be able to detect 50 ppb ammonia gas.

Photosensitizer Modulated Turn – off Fluorescence System and Molecular Logic Functions for Selective Detection of Arsenic (III)

AbstractThe As3+ directed selective Fluorimetric turn ‘OFF’ sensor based on dual functions of fluorophore‐metal interaction and electron transfer between the emitter and light sensitizing moiety (PB‐MOF) has been formulated. Intermolecular charge transfer dependent changes in emission intensity were recorded owing to the metal ion‐induced modifications in coordinating potentials of PB‐MOF. Fluorescein shows successive enhancement in emission maxima (λem=520 nm) due to intermolecular activation in the presence of AgNPs and PB‐MOF. While interaction with As3+ leads to non radiative energy transfer at λem=520 in methanol, and the action of As3+ is selective over other ions (Na+, K+, Cs+, Ca2+, Mg2+, Cr3+, Mn2+, W+, Zn2+, Cd2+, Pb2+). Signal modulations based on the associating capabilities of sensitizer were epitomized to construct the integrated molecular logic gate system of OR, NAND, INHIBIT with single and double inputs. The enhancement and quenching phases were well evaluated through analytical as well as Boolean functions.

Interaction of a hydrophilic molecule with bovine serum albumin: A combined multi-spectroscopic, microscopic and isothermal calorimetric study in the presence of graphene oxide

One of the most widely studied plasma protein is bovine serum albumin (BSA), and it plays a crucial role in the binding and transportation of many exogenous and endogenous drugs. Coumarin derivatives play a crucial role as an analgesic, anticancer, and anticoagulant agent. Here in this report, we have studied the binding interaction between a 7-amino coumarin derivative, namely 7-(N, N′-diethylamino)coumarin-3-carboxylic acid (7-DCCA) with BSA and also have found out the effect of graphene oxide (GO) on the binding interaction. The binding interaction was probed by employing various spectroscopic, microscopic, isothermal titration calorimetric (ITC), and by using molecular docking studies. The change in absorption and emission maxima position of BSA and 7-DCCA in the absence and presence of GO along with the change in absorbance and emission intensity when we titrated by 7-DCCA or BSA respectively indicates the strong complexation between 7-DCCA and BSA. From the fluorescence resonance energy transfer study, the average distance between tryptophan 213 of the BSA (donor), and the 7-DCCA (acceptor) is found ~50 Ǻ. From excited-state lifetime and fluorescence lifetime imaging (FLIM) studies, we observed that the average lifetime of 7-DCCA is much higher in the presence of BSA compared to buffer medium and in the presence of BSA a heterogeneous environment was created around 7-DCCA. Again in the presence of GO, the formation of a complex of 7-DCCA with a low concentration of BSA shows greater binding interaction as compared to that in the absence of GO. Time-resolved fluorescence anisotropy measurement shows that the addition of GO provides a restricted environment surrounding the 7-DCCA molecule in the presence of both low and high concentrations of BSA. CD study demonstrates the same extent of reduction of α-helical content of BSA protein on binding with 7-DCCA in the absence and presence of GO. ITC study revealed that the interaction between 7-DCCA and BSA is favoured by negative enthalpy change and positive entropy change. Also, from the ITC study, we find out that GO doesn't inflict significant change in the overall global binding interaction pattern, rather it inflicts changes in the mechanistic pathways of binding between 7-DCCA and BSA. Step-scan FTIR studies show the modification of amide I and amide II bonds with time when complexation occurs between BSA and 7-DCCA in the absence and presence of GO. The docking result reveals that the deprotonated form of 7-DCCA has positioned at a distance of ~3.7 nm from Trp 213. Thus these interactions play a central role in the development of coumarin derivative based small molecules to be used for both academic and industrial purposes.

Lanthanide-Based Nanosensors: Refining Nanoparticle Responsiveness for Single Particle Imaging of Stimuli.

Lanthanide nanoparticles (LNPs) are promising sensors of chemical, mechanical, and temperature changes; they combine the narrow-spectral emission and long-lived excited states of individual lanthanide ions with the high spatial resolution and controlled energy transfer of nanocrystalline architectures. Despite considerable progress in optimizing LNP brightness and responsiveness for dynamic sensing, detection of stimuli with a spatial resolution approaching that of individual nanoparticles remains an outstanding challenge. Here, we highlight the existing capabilities and outstanding challenges of LNP sensors, en-route to nanometer-scale, single particle sensor resolution. First, we summarize LNP sensor read-outs, including changes in emission wavelength, lifetime, intensity, and spectral ratiometric values that arise from modified energy transfer networks within nanoparticles. Then, we describe the origins of LNP sensor imprecision, including sensitivity to competing conditions, interparticle heterogeneities, such as the concentration and distribution of dopant ions, and measurement noise. Motivated by these sources of signal variance, we describe synthesis characterization feedback loops to inform and improve sensor precision, and introduce noise-equivalent sensitivity as a figure of merit of LNP sensors. Finally, we project the magnitudes of chemical and pressure stimulus resolution achievable with single LNPs at nanoscale resolution. Our perspective provides a roadmap for translating ensemble LNP sensing capabilities to the single particle level, enabling nanometer-scale sensing in biology, medicine, and sustainability.

Evaluation of a conserved tryptophanyl residue in donor substrate binding and catalysis by a phenol sulfotransferase (SULT1A1)

Structural determinations of members of the sulfotransferase (SULT) family suggest a direct interaction between a conserved tryptophanyl side chain and bound 3′-phosphoadenosine-5′-phosphate (PAP). We have prepared and purified mutants of the bovine SULT1A1, a very conserved homolog to the human SULT1A1, in which tryptophanyl-53 was sequentially trimmed to tyrosine, leucine, and alanine. Differential scanning fluorimetry indicated structural stabilities of the mutant proteins comparable to the wild type SULT1A1; however, less thermal stabilizations by PAP plus pentachlorophenol were observed with the mutants, suggesting weakened ligand binding. Protein fluorescence of the wild type enzyme decreased 6.5% upon binding PAP, whereas no changes occurred with the mutant enzymes. This reveals that W53, or its positional counterpart, has been the source of emission intensity changes used in previous investigations of other SULTs. Fluorescence resonance energy transfer from excited tryptophans to bound 7-hydroxycoumarin, as induced by PAP, indicated weakened binding of ligands to the mutant SULTs. This was also encountered and quantified in initial rate kinetic analyses. Ablation of the PAPS adenine-to-W53 ring interaction, shown by the W53A mutant enzyme, resulted in a 6.4-fold increase in KPAPS and a 92% decrease in kcat/KPAPS. Measured KPAPS values reveal the W53 indole ring contribution to PAPS binding to be 1.1 kcal/mol (4.6 kJ/mol). These results verify the structurally-inferred role for the π−π stacking interaction between PAP(S) and the conserved tryptophanyl residue in SULT1A1 and other members of the SULT family.

Carrier dynamics and recombination in silicon doped InAs/GaAs quantum dot solar cells with AlAs cap layers

The effects of doping InAs quantum dots (QDs) with Si on charge carrier dynamics and recombination in the InAs/GaAs QD solar cells (QDSCs) with AlAs cap layers was investigated. Non-radiative and radiative recombination paths in the doped cells were identified by changes in emission intensity, long-wavelength photovoltage (PV) as well as time-resolved PV and photoluminescence (PL) measurements. We find that the reduction of long-wavelength PV and PL with n-doping is due to the electron population of the QD ground states (GSs) and shrinkage of the depletion layer. The time constants, derived from the time-resolved PV, grow non-monotonically with increasing of the doping density in the QDs due to redistribution of electrostatic potential in the intrinsic region of p-i-n diode and electron population of EL2 defect states of GaAs barriers. We also find that the GS emission from the InAs QDs decreases with n-doping. The results show that PL traces depend on carrier dynamic in the top QD layers populated partially with electrons from ionized impurities, whereas PV transients were found to be strongly dependent on recombination via QD and defect states located outside the depletion layer. We conclude that the non-radiative recombination of photogenerated electrons and holes via defects is suppressed due to the spatial separation by the local electric fields in and around doped AlAs/InAs QDs, as the potential profile of the intrinsic region is modulated spatially by built-in charges. The interpretation of experimental data suggests limiting mechanisms in the InAs/GaAs QDSCs operation and sheds light on possible approaches for their further improvement.

Synthesis of Cit-NaYF4: Yb, Tm@phenolic formaldehyde resin (PFR)@Au composites as an optical sensor for the detection of Cu(Ⅱ) ions

Abstract A facile hydrothermal method was employed to synthesize the core-shell structure up-conversion Cit-NaYF4:Yb, Tm (UC)@phenolic formaldehyde resin (PFR) nanoparticles (NPs). UC NPs can enhance the emission intensity of the PFR shell, which contributes to improving the fluorescence detection sensitivity of UC@PFR NPs. Au NPs were loaded onto the surface of PFR shell in situ through the good reduction of the hydroxyl group in PFR. The emission intensity of UC@PFR decreased greatly in the presence of Au nanoparticles due to fluorescence resonance energy transfer (FRET) mechanism between UC@PFR and Au NPs. However, the mixture of H2O2 and SCN− could prevent the decrease of emission intensity of UC@PFR@Au composites because of the oxidation reaction between H2O2 and Au nanoparticles in the presence of SCN−. Also, Cu2+ can prevent the oxidation reaction to occur, which results in the slight change of emission intensity of UC@PFR@Au in the presence of H2O2 and SCN−. Thus, the as-synthesized UC@PFR@Au particles were used to detect Cu2+ sensitivity. The good linear correlation equation between the fluorescence intensity of UC@PFR@Au particles and the concentration of Cu2+ in the range of 4–90 nM (R2 = 0.99) was established with the low detection limit (LOD) of 0.54 nM. Furthermore, the as-synthesized particles were employed to detect Cu2+ in the actual water sample with satisfying results.

Quantitative Analyses of Förster Resonance Energy Transfer between Identical Pyrene Chromophores (Homo‐FRET) In DNA Scaffolds.

AbstractFörster resonance energy transfer between identical chromophores (homo‐FRET) has been difficult to analyze since neither emission intensity nor lifetime changes with the occurrence of homo‐FRET. Herein we used a DNA scaffold to analyze homo‐FRET between pyrene moieties. The DNA scaffold was modified with two pyrenes and a quencher, anthraquinone. Homo‐FRET was detected by monitoring quenching of pyrene emission and the decrease in the fluorescence lifetime of pyrene. Homo‐FRET efficiencies could be calculated by excluding effects of hetero‐FRET. The experimentally determined efficiencies showed an excellent agreement with Förster theory. These results will inform design of novel molecular probes and light‐harvesting antennae.

Noninvasive optical temperature sensing behavior of Ho3+ and Ho3+/Er3+ doped tellurite glasses through up and down-converted emissions

Optical temperature sensing behavior of Ho3+ and Ho3+/Er3+ doped tellurite glasses are investigated in terms of fluorescence intensity ratio (FIR) method in the range of 298–558 K. Thermal studies reveal that proposed glasses are stable up to approximately 613 K. Optical thermometry investigations are carried out through temperature dependent up- and down-converted photoluminescence (PL) emissions. Richness of the up-converted PL spectrum provides versatility, therefore along with the down-conversion spectrum FIRs of four different emission band pairs are calculated and evaluated. Each pair demonstrates varying sensitivity values in the detectable temperature range. Pump power is altered in up-conversion regime from 0.45 to 0.90 W to investigate the rate of change of emission intensities. Reliability of the FIRs is confirmed after several heating-cooling cycles. Judd-Ofelt analysis is also adopted to estimate radiative properties and temperature sensing capabilities of the proposed glasses. The highest possible absolute and relative sensitivities are determined as 0.0172 K−1 and 2.48 % K−1, respectively indicating the potential of Ho3+/Er3+ doped tellurite glasses for their use in noninvasive optical temperature sensing applications.

Optical actinometric measurements of nitrogen impurity in Ar/He microwave discharge during wall cleaning of MT-I spherical tokamak

During the wall conditioning of the MT-I spherical tokamak, the addition of nitrogen impurity in the argon and helium microwave discharges has been investigated using the optical actinometric technique. This simple technique exploits the change in emission intensity of the selected Ar/He lines at constant partial pressure to normalize the electron energy distribution function with changing plasma conditions provided that both transitions have close excitation thresholds and similar dependence of excitation cross-sections. Accordingly, the selected line intensity of the nitrogen can be related to the ground state concentration of the nitrogen molecules and ions involving in optical emission. The electron temperature for both discharges has been determined separately from the Boltzmann plot method. For measurement of electron number density empirical formulas have been derived from the isolated spectral lines of Ar–I (750.38 nm) and He–I (587.56 nm & 667.81 nm). Stark broadening of well-isolated argon Ar–I (750.38 nm) and helium He–I (587.56 nm & 667.81 nm) lines have been used after de-convolution of other broadening contributions. It is observed that the electron temperature reduces with time indicating the plasma cooling with the addition of nitrogen impurity in the chamber.

Correlated Exciton Fluctuations in a Two-Dimensional Semiconductor on a Metal.

Excitons in nanoscale materials can exhibit fluorescence fluctuations. Intermittency is pervasive in zero-dimensional emitters such as single molecules and quantum dots. In contrast, two-dimensional semiconductors are generally regarded as stable light sources. Noise contains, however, valuable information about a material. Here, we demonstrate fluorescence fluctuations in a monolayer semiconductor due to sensitivity to its nanoscopic environment focusing on the case of a metal film. The fluctuations are spatially correlated over tens of micrometers and follow power-law statistics, with simultaneous changes in emission intensity and lifetime. At low temperatures, an additional spectral contribution from interface trap states emerges with fluctuations that are correlated with neutral excitons and anticorrelated with trions. Mastering exciton fluctuations has implications for light-emitting devices such as single-photon sources and could lead to novel excitonic sensors. The quantification of fluorescence fluctuations, including imaging, unlocks a set of promising tools to characterize and exploit two-dimensional semiconductors and their interfaces.

The effect of heat treatment on the front-face fluorescence spectrum of tryptophan in skim milk

The effect of heat treatment on tryptophan front-face fluorescence emission spectra of reconstituted skim milk was assessed. Samples were heat-treated from 70 to 100 °C at six holding times. Treating milk at 90 and 100 °C induced a decrease in fluorescence intensity (∼37 and ∼47 %) and a red shift (12 and 14 nm), respectively, with both parameters significantly affected at 99.9 % by temperature, time, and the interaction of both factors. Red shift, which could be attributed to whey protein denaturation and tryptophan exposure to increasing solvent polarity, was found to follow a quadratic trend as a function of holding time (from 0 to 60 min). The decrease of fluorescence intensity observed at those two temperatures and in the mentioned holding time range was also a quadratic function of the associated red shift. Emission intensity change at a single wavelength (∼340 nm) was partly caused by direct intensity decrease and indirectly due to the emission maximum shift. Tryptophan fluorescence allowed sample classification by PCA analysis according to heat load, i.e., temperature and time. These results established the bases for development of a cost-effective sensor based on simple, economic optical components for measurement of a few well-selected emission wavelengths, which associated with data processing, should allow inline control of milk heat treatment.

Fluorogenic sulphate anion sensor with INHIBIT logic gate by dinuclear Zn (II) complex: Synthesis, emission, DFT studies

N4O3 coordinating heptadentate non emissive ligand emits strong blue emissive light only in the presence of Zn(II) ion. This ligand yields a solid crystalline μ-phenoxo bridge dinuclear Zn(II) complex 1a. The binding stoichiometry, binding constant and binding affinity of the complex in solution state has been studied here. The UV–vis, Emission, 1H NMR and ESI-MS several spectroscopic ratiometric titration of the ligand in presence of zinc ion revealed that the major part of the solution contained dinuclear form of the complex over the mononuclear form. Theoretical interpretation also justifies this dimeric behavior of the complexation in solution state. The complex was examined with varied types of anions, such as H2PO4□, HPO42−, PO43−, SO42−, F−, Br−, Cl−, I−, AcO−, NO3–, ATP and ADP. The dinuclear species was found to act as a highly selective and sensitive receptor for tetrahedral SO42− by fluorescence ON-OFF signaling through the formation of sulphato bridging dinuclear complex 1b. The photo physical properties of both the complexes have been correlated by DFT and time-dependent DFT (TDDFT) method. The emission intensity changes of this dinuclear complex during the addition of sulphate anion is useful to construct an INHIBIT logic gate at the molecular level, by means of Zn2+ and SO42− ions as chemical inputs and the emission intensity as output signal.

Optimum pressure range evaluation toward aerodynamic measurements using PSP in low-pressure conditions

In the present study, new performance evaluation parameters for pressure-sensitive paint (PSP) were proposed, and the effects of ambient pressure on the characteristics of the PSP were evaluated. The proposed parameters allow us to determine the optimal pressure range on the basis of the following quantities: (1) the Stern–Volmer coefficient, (2) the normalized pressure sensitivity to intensity changes due to flow-induced pressure fluctuations, (3) the change in the intensity of PSP emissions in response to the given change in pressure, and (4) the signal-to-noise ratio of the change in the PSP emission intensity due to flow-induced pressure fluctuations. The characteristics of several types of PSP were evaluated using the proposed parameters. It was demonstrated that the proposed parameters enable a comparison of the effects of ambient pressure on the characteristics of PSP, and the optimal pressure range for aerodynamic measurements could be successfully identified for the different PSP.