Excellent Luminescence Stability Research Articles

Crystallization and luminescence properties of stable CsPbBr3 Nanocrystals in Li2B4O7 glass

All-inorganic CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals (NCs), have achieved unprecedented advances in opto-electronic applications. However, issues such as poor stability and the volatility of halides in the preparation process continue to hinder their practical applications. Here, lithium tetraborate (Li2B4O7) was chosen as the glass matrix to prepare CsPbBr3 NCs glasses through traditional melting-quenching and heat treatment processes, effectively reducing the glass synthesis temperature to 940 °C. The heat treatment temperature and duration are examined. The Li2B4O7 glass matrix exhibits a uniform structure and high transmittance and CsPbBr3 NCs precipitated uniformly after heat treatment. Among these glasses, the sample heat-treated at 510 °C for 5 h exhibited an optimal photoluminescence quantum yield of 76.1 % and the narrowest full width at half maximum values of 24 nm. Its photoluminescence intensity maintained 96.6 % of its original value after multiple thermal cycles and thermal shocks, demonstrating the sample's robust thermal stability. Finally, by integrating the CsPbBr3 NCs glass sample with a blue chip in simple device packaging, a green light-emitting diode was successfully fabricated, featuring excellent luminescence stability and a color purity of up to 96.4 %, promising for applications in solid-state lighting and display technologies.

Supramolecular Assembly of Hydrogen-Bonded Organic Frameworks with Carbon Dots: Realizing Ultralong Aqueous Room-Temperature Phosphorescence for Anticounterfeiting.

Room-temperature phosphorescent carbon dots (RTP-CDs) have received increasing attention due to their excellent optical properties and potential applications. Nevertheless, the realization of RTP-CDs in aqueous solutions remains a considerable challenge due to the water-molecule- and oxygen-induced deactivation of the triplet excitons, which leads to phosphorescence quenching. In this study, ultralong phosphorescence in water was achieved by in situ self-assembly of CDs encapsulated in a rigid hydrogen-bonded organic framework (HOF). The phosphorescence lifetime reaches an impressive 956.96 ms and exhibits long-lasting optical and structural stability in water for more than 90 days. The composite material not only has ultralong luminescence life and excellent luminescence stability but also has two-color phosphorescence emission, as well as excellent antiphotobleaching and phosphorescence stability in aqueous solution, which can solve the current problem that RTP is easily burst out by water and moisture. In addition, this study introduced a fluorescent dye based on the triplet-singlet Förster resonance energy transfer system (TS-FRET) to fine-tune the afterglow properties. This work will inspire the design of RTP systems with dual phosphor light sources and provide new strategies for the development of smart RTP materials in water.

Enhanced thermal and water stability of halide perovskite MAPbBr3 by double-coated hydrogen-bonded polymer network

MAPbX3 (X = Br, I, Cl) type lead halide perovskite has great potential for light-emitting devices due to its excellent optical properties; however, their degradation under the influence of heat and atmospheric moisture severely limited their applications. To address this issue, we used a dynamic hydrogen bonding network constructed by amino-terminated hyperbranched aminoglycoside polymer (AHP) and thermoplastic polyurethane (PUIP) to double-coat MAPbBr3. The thermal and water degradation of MAPbBr3 was greatly alleviated upon formation of the MAPbBr3@AHP@PUIP composite. The structures of AHP, PUIP, MAPbBr3@AHP, and MAPbBr3@AHP@PUIP films were characterized by various techniques. The double-coated MAPbBr3@AHP@PUIP film exhibited high quantum efficiency and excellent luminescence stability at room temperature, with quantum yields remained above 90 % of the original value even after 20 days in air. Moreover, the polymer film still maintains high fluorescence emission after 72 h in the water phase, and can achieve fluorescence recovery transformation at a specific temperature, and has a good self-healing property at room temperature. This inexpensive and convenient method not only greatly enhanced PL efficiency, increased water stability, but also demonstrated excellent flexibility and elasticity, suggesting broad prospects for the commercial application of inorganic perovskite materials in flexible electronics.

LED application and temperature-sensitive properties of white carbon dots doped with aluminum triacetylacetone without the N element

CD phosphors are well light up in solution but tend to undergo powder-based solid-state aggregation quenching. Solid-state aggregation quenching is an important flaw in LED applications. Moreover, most one-component, white CD phosphors are obtained using doping of various valences of N. White CDs that are not doped with N have yet to be reported. In this work, we attempted to develop white aluminum triacetylacetone-doped CDs (Al-CDs) phosphors with resisted solid-state aggregation quenching for LED applications. The Al-CDs do not contain N element and emit broadband white light from 420 to 800 nm, and their emission centers can redshift or blueshift with increasing contents of aluminum triacetylacetone. Al-CDs phosphors exhibit excellent luminescent stability at high temperature (570 K) and under natural conditions (80 days). Their afterglow time increases as the concentration of aluminum triacetylacetone increases and can reach 10 seconds. In addition, the luminescent mechanism and temperature-sensitive properties of the Al-CDs phosphors were investigated.

High-entropy perovskite quantum dots of rare earth synergy with excellent luminescence stability via high-energy ball milling

The problem of low stability and high lead content limit the commercial development of halide perovskite. In this paper, the high-energy ball milling is used to rapidly and efficiently synthesize high-entropy Cs(Pb1/5Mn1/5Ni1/5Zn1/5Yb1/5)Cl3 quantum dots (QDs), the introduction of high-entropy and rare earth ions reduces lead content, increases mixing entropy, and synergistically enhances the photoluminescence (PL) intensity and stability of QDs with other ions. Because the increase of entropy enhances the stability, the QDs still have 70 % PL intensity after 60 days of placement. After the QDs are exposed to the ultraviolet lamp for 8 hours, the PL intensity maintains at 67.1 % due to the loss of ligand. Ionic bonds are easily broken in water, so after soaking in water for 8 hours, the PL intensity of the QDs keeps at 32 %. The thermal stability of QDs is maintained well because of physical and chemical stability of rare earth ions. Since ethanol dissolves the ligands on the surface of the QDs, the non-radiative recombination is enhanced, so the PL intensity of QDs remains at 59 % after soaking for 8 hours. This paper provides a new way that further enhances the stability and solves high lead content of all-inorganic perovskite materials.

Two water-stable Cd(II)-based coordination compounds as a fluorescent sensor for selective and sensitive detection of antibiotics

Developing highly stable materials for harmful compound detection in a water environment is of much importance and challenge. we report two cadmium based fluorescent coordination compounds with formula [Cd(HL)(phen)(H2O)3] (1) and [Cd(HL)(2,2′-bipy)(H2O)2] (2) where H3L = 4-(N,N’-bis(4-carbonylbenzyl)amino)-3-methylbenzenesulfonic acid, phen = 1,10-phenanthroline monohydrate and 2, 2′-bipy = 2, 2′-bipyridine. Details structural studies showed that compounds 1 and 2 are mononuclear and binuclear discrete compounds, respectively. Its excellent luminescence stability in aqueous solutions, coupled with outstanding thermal and chemical stabilities, enables it to function as an efficient detector for metamitron (MMT). It boasts a limit of detection of 2.72 ppm and exhibits quenching constant (KSV) values of 0.09, making it an effective luminescent sensor for detecting MMT. The luminescence quenching of the compound 1 by MMT was attributed to competing absorption and photoelectron energy transfer mechanisms.

A Tb-MOF sensor with sensitive detection of tryptophan and dopamine hydrochloride

Based on a 3-(2,4-dicarboxylphenyl)-6-carboxylpyridine ligand (H3dpcp), a Tb-MOF with the square hole was synthesized, namely, [Tb(dpcp)(H2O)]n (1). Complex 1 is porous three-dimensional structure and exhibits excellent luminescence stability within a certain range of pH 3–11 in aqueous solutions. It is noteworthy that complex 1 can selectively recognize tryptophan by the fluorescence quenching with high sensitivity, anti-interference, and recyclability; while complex 1 can also achieve sensitive detection of dopamine hydrochloride. Furthermore, the fluorescent sensing mechanisms of complex 1 for tryptophan and dopamine hydrochloride has been illustrated in detail.

High stability of robust anti-thermal-quenching lead-free double perovskite crystals for optoelectronic devices and high-performance fibers

Sb3+-doped Cs2NaHoCl6 perovskite crystals were synthesized through an efficient and energy-saving method. The flexible luminescent fibers prepared from Sb3+-doped Cs2NaHoCl6 exhibit excellent luminescent stability in high-temperature environments.

Ultra-stable CsPbBr3-embedded polymer films for spectrally tunable X-ray nuclear batteries and flexible radiation imaging applications

CsPbBr3-embedded polystyrene films exhibit excellent luminescence stability in various environments and have the special advantages of achieving spectral regulation of radioluminescent nuclear batteries and X-ray imaging of irregular objects.

A novel one-dimensional Y2(Zr0.6Ti0.4)2O7:Eu tube-in-tube nanostructure fabricated by a single-nozzle electrospinning technique and its low color drift property at high temperature

1D Y2(Zr0.6Ti0.4)2O7:Eu tube-in-tube nanostructures were fabricated by a simple single-nozzle electrospinning method. These materials exhibit excellent luminescent stability and lower color drift performance at high temperatures.

Centimeter-Sized Single Crystals of Tetrahedral Manganese (II) Halide Hybrids for Wide-Color Gamut Backlighting Displays.

Phosphors with narrow-band green emissions and high photoluminescent quantum efficiency (PLQY) are significantly required for backlighting displays with wider color gamut. In this work, two centimeter-sized manganese (II) halide single crystals TMG2MnCl4 and TMG2MnBr4 (TMG = 1,1,3,3-tetramethylguanidine) are synthesized, exhibiting bright narrow-band green emissions with high PLQYs up to 62% and 90%, respectively. The narrow-band green light emission is located at 520nm with a full-width at half-maximum (FWHM) of only 57nm. The photoluminescence mechanisms of two single crystals are elaborated. Two white-light-emitting diodes for backlighting displays (BD-WLEDs) based on them are fabricated, exhibiting the widest color gamut of 122% National Television Standards Committee (NTSC), and a luminous efficacy reached ≈93lmW-1 with excellent luminescence stability at high temperatures. These properties indicate the potential applications of tetrahedral manganese (II) hybrids in wide-color gamut backlighting displays.

Bright solid-state luminescence and high-temperature resistance of Ga-doped carbon dots with ultra-wideband white emission for light-emitting diodes.

Fluorescent CDs tend to undergo solid-state aggregation quenching in powder form. This is caused by the stacking of π-π conjugate structures and excessive resonant energy transfer. Moreover, various forms of N play an important role in white CDs suitable for LED applications. White, single-component, non-N-doped CDs have never been reported for LED application. In this study, to overcome this limitation, we developed Ga-doped CD powders containing no N element that exhibit ultra-wideband white emission in the range of 420-800 nm for LED applications and were able to resist solid-state aggregation quenching. Furthermore, the Ga-doped CD powders demonstrated excellent luminescence stability under high temperatures. Another strength of the Ga-doped CD powders is their large Stokes shift, where the peak center of white emission shifts from 550 nm to 650 nm under 365 nm excitation as the Ga doping concentration is adjusted from 0.05 to 0.6 (Ga : H2O, mass ratio). The full width at half-maximum can reach 262 nm. Additionally, the Ga-doped CD powders exhibit good luminescence stability under long-time exposure to an air atmosphere. Their luminescent intensity retained 70%-74% of the initial values even after being left in natural placement for 100 days. Moreover, the Ga-doped CDs demonstrate afterglow features.

Ultra-stable dual-color phosphorescence Carbon-Dot@Silica material for advanced anti-counterfeiting

Room temperature phosphorescence (RTP) materials have motivated massive attention due to their great advantages in anti-counterfeiting and optical encryption. However, the commonly used carbon-based RTP materials suffer from drawbacks of photobleaching, quenching and single phosphorescence color outputs, which obstruct their performance in high-level anti-counterfeiting techniques. Herein, we present a universal method for the fabrication of a carbon-dot@silica (CDs@SiO2) composite that possesses ultralong lifetime, high phosphorescence quantum efficiency (PQE), excellent luminescence stability, and dual-color phosphorescence emission. Taking advantage of the restriction by rigid network of SiO2 and stable covalent bonding between CDs and SiO2, the triplet excited states of CDs are stabilized. As a result, the CDs@SiO2 exhibit ultralong lifetime of 1.33 s and 0.38 s under excitation at 254 nm and 365 nm, respectively. Furthermore, the phosphorescence color of CDs@SiO2 can change from cyan to yellow when the exciting wavelength switches from 254 nm to 365 nm. The obtained CDs@SiO2 also exhibit outstanding characteristics of anti-photobleaching and phosphorescence stability in an aqueous solution. Based on the unique phosphorescent properties of the CDs@SiO2, a stable and dual-color phosphorescence security label is designed for advanced information encryption.

Flexible and foldable films of wCDs/BNNS-OH/PVA white light composite with high stability and heat dissipation

Recently, carbon dots (CDs) have gained much attention in optoelectronic fields on account of their superior optical and environmentally friendly properties. Nevertheless, aggregation-induced quenching (AIQ) effect of solid-state CDs and thermal quenching caused by high temperatures severely hinders their further development. Herein, a novel wCDs/BNNS-OH hybrid nanostructure was synthesized by combining blue CDs (bCDs) and yellow CDs (yCDs) to the hydroxylated boron nitride nanosheets (BNNS–OH) surface. The uniform dispersion of CDs in BNNS-OH effectively alleviates the undesirable AIQ effect, and enables CDs/BNNS-OH composites to have color-tunable fluorescence characteristics. The wCDs/BNNS-OH/PVA composite film was obtained by encapsulating wCDs/BNNS-OH into polyvinyl alcohol (PVA). The film exhibits excellent luminescence stability in the air, ultraviolet light, water, and high-temperature environment. Meanwhile, since wCDs/BNNS-OH establishes an effective heat transfer channel in the PVA matrix, the working temperature of CDs in the wCDs/BNNS-OH/PVA film is greatly reduced. Moreover, the prepared wCDs/BNNS-OH/PVA film is flexible enough to retain the photoluminescence intensity unchanged after thousands of bending cycles. This high stability and heat dissipation wCDs/BNNS-OH/PVA composite film will facilitate the application of CDs in flexible and foldable lighting devices.

Ultrastable Photoluminescence Enabled by 1D Rare-Earth Metal-Organic Frameworks Based on Double Thiacalix[4]arene-Capped Nodes.

Luminescent stability is a vital factor that dictates the application of lanthanide luminescent materials. Designing luminescent lanthanide cluster nodes that form an extended framework with predictable linking patterns may help enhance the structural stability of the lanthanide complexes and hence lead to improved luminescent stability. Herein, we report a series of one-dimensional (1D) rare-earth metal-organic framework compounds, {Ln4(μ4-OH)(TC4A)2(H2O)2(CH3O)(HCOO)2(HCOOH)}·xCH3OH (Ln = Sm (1), Eu (2), Tb (3), Dy (4); x = 1-5), based on double thiacalix[4]arene-capped Ln4(μ4-OH)(TC4A)2 nodes. The axially capped Ln4(μ4-OH)(TC4A)2 nodes are connected equatorially by formate bridges to form zigzag 1D-metal-organic framework (MOF) chains, which further assemble into a quasi-two-dimensional (2D) structure via hydrogen bonding. These unique features result in a stable structure and therefore superior luminescent stability. For example, the Tb-based 1D-MOF (3) exhibits intensive green photoluminescence with a quantum yield of 53% and an average decay time of 1.33 × 106 ns. It maintains its integrated emission intensity at 96.5, 94.5, and 89.4% of the original value after being exposed to moisture (soaking in water for 10 days), elevated temperature (150 °C), and UV (15 days of continuous radiation), respectively, demonstrating excellent luminescent stability. We adopt the Tb-based 1D-MOF (3) as the green phosphor and successfully fabricate a prototype white-light-emitting diode (LED) with stable emission under long-term operation. Our synthetic strategy allows control over the linking pattern of lanthanide nodes, providing a predictive route to obtain lanthanide MOFs with improved luminescent stability.

Excitation wavelength-dependent continuous color-tunable luminescence of fluorescent dyes encapsulated into lanthanide metal-organic framework for anti-counterfeiting

Excitation dependent luminescent materials, which have attracted significant scientific attention in the field of information security owing to information storage and luminescence properties. However, it remains a formidable challenge in developing excitation dependent luminescent materials with a simple synthesis method and predictably modulated luminescent outputs. Herein, a novel Ln3+/Fluorescent dyes@MOFs strategy is developed to generate excitation dependent continuous color-changing luminescent materials via a hydrothermal method and post-synthetic modification (PSM), based on metal-organic frameworks (MOFs) matrix doped with lanthanide cations and fluorescent dyes encapsulated into the lanthanide MOFs. The continuous proportional emission of mixed luminescence appeared within a single matrix in response to the different excitation wavelength and the proportional emission control (PEC) mechanism between the two luminescent centers is proposed. In addition, the photoluminescence platform demonstrates a distinct security method based on covert color that are controlled by distinct excitation wavelengths and excellent luminescence stability have also been verified in these new materials.

Water‐Durable Cesium Lead Halide Perovskite Nanocrystals Passivated with a Cationic Gemini Surfactant

AbstractChemical states of perovskite nanocrystal surfaces are vital to withdraw their intrinsic optoelectronic nature and maintain the colloidal stability. This study reports that the cationic gemini surfactant alkanediyl‐α,ω‐bis(dodecyldimethylammonium bromide) “12‐n‐12” dramatically improved the luminescence properties and chemical stability of cesium lead bromide nanocrystals (CsPbBr3 NCs). Dispersion stability of CsPbBr3 NCs passivated with 12‐n‐12 (n = 3−7) is enhanced with the methylene spacer length, their dynamic light scattering studies ensure that the gemini ligands with more than the pentyl methylene spacer exhibit mono dispersion of NCs. Nuclear magnetic resonance and X‐ray photoemission spectroscopy studies reveal that 12‐n‐12 is bound to the surfaces of CsPbBr3 NCs with a density of 0.74−1.06 nm−2 which is less than half the didodecyldimethylammonium bromide (DDAB) ligand density. Nevertheless, CsPbBr3 NCs with the 12‐n‐12 shell exhibit a high photoluminescence quantum yield equal to that of DDAB. Furthermore, the 12‐n‐12 shell demonstrates remarkably excellent luminescence stability when the NC solution is exposed to water. Hence, 12‐n‐12 is a promising candidate to substitute the conventional ligands.

Magneto-optical and fluorescence properties of Tb3+ doped glass-ceramics containing AlPO4

In this paper, Tb3+ doped AlPO4 magneto-optical glass-ceramics were prepared by traditional melt quenching process and heat treatment techniques. The crystal structural, morphology, magneto-optical and fluorescence properties were systematically characterized via X-ray diffraction (XRD), projection Electron Microscope (STEM), Faraday rotation Angle test, photoluminescence spectra and fluorescence decay time. The transmittance curve shows that the visible light transmittance can reach 78% at least. Magneto-optical properties of Tb3+ doped magneto-optical glass-ceramics were studied. When the incident wavelength is 633 nm, the 27B2O3-23GeO2-20Al2O3-28Tb2O3-2P2O5 glass is heat-treated for 15h, the Verdet constant reaches -118.31 rad/(T•m), the transmission rate is 81%. In addition, the luminous intensity of the prepared glass-ceramics decreases with the growth of AlPO4 crystallites. According to the CIE coordinate chart, all the coordinates are in the green range, and the chromaticity coordinates do not change significantly with the heat treatment time, indicating that the glass-ceramics prepared in this study have excellent luminescence stability.

Hydrothermal synthesis of bright blue-emitting carbon dots for bioimaging and fluorescent determination of baicalein

Bright blue-emitting CDs (B-CDs) with a considerable QY of 66 % were synthesized from precursors of cysteine, trisodium citrate dehydrate and ethylenediamine by a simple hydrothermal method. Excellent luminescence stability with various pH, salt concentrations, storage time and UV radiation time is found with excitation-independent emission. Based on the good biocompatibility, B-CDs was successfully used for fluorescence imaging of human ovarian cancer cells. Moreover, the B-CDs were confirmed to be capable of baicalein sensing with a good linear relationship in range of 0–30 μM and the limit of detection of 33 nM. The corresponding sensing mechanism was proved to be fluorescence internal filtration effect and the static quenching effect. All results demonstrate that the B-CDs have good potential of the versatile utilization in biology-relevant fields.

A stable terbium(III) metal-organic framework as a dual luminescent sensor for MnO4− ions and nitroaromatic explosives

A new terbium(III) metal-organic framework [Tb2(BTZ)(μ2-H2O)(μ3-OH)2] (ZH-101, H2BTZ ​= ​3.5-bis(4’-carboxy-phenyl)-1,2,4-triazole) was synthesized with BTZ ligands under solvothermal conditions for the luminescent study. It is constructed of [Tb2(μ2-O)(μ3-O)2]n 2D layered structure and is further connected by BTZ ligands with rich triazole-N sites to form a water-stable 3D net framework. ZH-101 displays excellent chemical stability in common organic solvents and water in the wide pH range of 0–11. The luminescence test experiment of ZH-101 in water containing different anions shows selective fluorescence quenching for MnO4− with low detection limit (0.16 ​mM). In addition, ZH-101 also displays excellent luminescence stability in different solvents and can selectively detect nitroaromatic explosives in DMF solutions, especially for 4-nitrophenol with Ksv ​= ​3.38 ​× ​104 ​M-1, and low detection limit of 0.20 ​mM. It still retains original fluorescence intensity and chemical stability after five cycles experiments, exhibiting remarkable long-term cycle and reversibility. Therefore, ZH-101 is a competitive and promising candidate for sensing MnO4− ions and nitroaromatic explosives.