Yellow Emission Research Articles

Monometallic heteroleptic complexes of Dy(III) ion incorporating β-diketone and ancillary moieties: Photophysical and electrochemical analyses

Several luminescent ternary dysprosium complexes were synthesized and examined using diketone ligand 1,3-diphenylprop-1,3-dione (DPD) and various auxiliary ligands. Spectroscopic analysis was carried out to determine the structural and photophysical features of Dy (III) complexes. IR and proton NMR spectroscopic studies suggested the bonding of chelating moieties to the metal ion through oxygen and nitrogen atom. The optical and electronic band gap is evaluated which proposed the conducting behaviour of dysprosium complexes. Upon excitation with UV radiation, three distinct emission peaks of the Dy (III) ion are appeared at about 485 nm (J = 15/2), 575 nm (13/2) and 664 nm (11/2) corresponding to the transitions of type 4F9/2 → 6HJ. The strongest emission peak obtained at ∼ 575 nm is responsible for yellow emission of Dy (III) complexes. The yellow to blue (Y/B) ratio estimated for the transition J = 13/2 / J = 15/2 were found to be in the range of 4.19 – 2.80. The quantum yield was also determined for the Dy (III) complexes which is as: Φ1 = 0.315, Φ2 = 0.261, Φ3 = 0.183, Φ4 = 0.157. The synthesized dysprosium complexes demonstrate luminescence lifetime in decreasing order i.e. 0.600 ms > 0.510 ms > 0.431 ms > 0.323 ms. Furthermore, the chromaticity coordinates also confirm their yellow luminous behavior. These newly synthesized complexes could be utilized for developing systems significant for lighting, OLEDs and displays due to their luminous features.

Multi-mode photoluminescence inks based on lanthanide-doped multilevel core-shell microspheres for advanced anti-counterfeiting applications

Development of advanced luminescent nanomaterials and technologies is of great significance for anticounterfeiting applications in global economy, security, and human health. In this work, we have designed two types of anti-counterfeit materials. (1) The dual excitation mode core–shell microsphere is based on SiO2 core, with the GdVO4:Yb,Er upconversion luminescent inner layer, SiO2 shell separator, and Gd2O3:Eu@SiO2 downconversion luminescent layer are sequentially deposited on it via co-precipitation method. The microspheres have a five-layer core–shell structure with an overall diameter of ∼ 146 nm and enables the spatial separation of Er3+ and Eu3+, which prevents the cross-relaxation of Er3+. The microspheres were prepared into an upconversion/downconversion excitation mode luminescent ink, with inkjet-printed patterns that only extract information when excited by 254 nm and 980 nm excitation. (2) The core–shell-shell SiO2@AIPA-S-Si-Tb@SiO2 microspheres have been synthesized by using organic ligands ((HOOC)2C6H3NHCONH(CH2)3Si(OCH2CH3)3) (defined as AIPA-S-Si) connected with Tb3+ ions and silica through covalent bond. The microspheres have a sandwich structure with an overall diameter of ∼ 100 nm and show bright green light. The sandwich structure and five-layer core–shell structure was mixed proportionally to obtain orange-red, white, and yellow emission ink under 254 nm, green emission under 310 nm, and green emission under 980 nm excitation.

Spectrally Tunable Lead-Free Perovskite Rb2ZrCl6:Te for Information Encryption and X-ray Imaging.

A series of lead-free Rb2ZrCl6:xTe4+ (x = 0%, 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 5.0%, 10.0%) perovskite materials were synthesized through a hydrothermal method in this work. The substitution of Te4+ for Zr in Rb2ZrCl6 was investigated to examine the effect of Te4+ doping on the spectral properties of Rb2ZrCl6 and its potential applications. The incorporation of Te4+ induced yellow emission of triplet self-trapped emission (STE). Different luminescence wavelengths were regulated by Te4+ concentration and excitation wavelength, and under a low concentration of Te4+ doping (x ≤ 0.1%), different types of host STE emission and Te4+ triplet state emission could be achieved through various excitation energies. These luminescent properties made it suitable for applications in information encryption. When Te4+ was doped at high concentrations (x ≥ 1%), yellow triplet state emission of Te4+ predominated, resulting in intense yellow emission, which stemmed from strong exciton binding energy and intense electron-phonon coupling. In addition, a Rb2ZrCl6:2%Te4+@RTV scintillating film was fabricated and a spatial resolution of 3.7 lp/mm was achieved, demonstrating the potential applications of Rb2ZrCl6:xTe4+ in nondestructive detection and bioimaging.

Senna auriculata extract-assisted biogenic synthesis of yellow emissive gold nanoclusters for quantitative detection of glyphosate in food and environmental samples

The green chemistry approach was unitized for the development of fluorescent nanomaterial. The objective of this study is to develop plant-based fluorescence nanomaterials via environment-friendly and biocompatible approach. Here, water-soluble yellow emissive gold nanoclusters were synthesized by using extract of Senna auriculata leaves and 1.25 mM of HAuCl4·xH2O via microwave-assisted method. Senna auriculata-AuNCs (S. auriculata-AuNCs) exhibit excellent solubility, good quantum yield (QY), stability, and biocompatibility. The ultra-small (<5 nm) size of S. auriculata-AuNCs displayed yellow emission and were characterized by using fluorescence, UV–visible, FT-IR, HR-TEM, zeta potential, DLS, XPS, and XRD techniques. S. auriculata-AuNCs display an intense emission of 620 nm when excited at 500 nm. The as-synthesized S. auriculata-AuNCs act as an effective sensor for sensing glyphosate pesticide via the “turn-off” mechanism. Moreover, S. auriculata-AuNCs showed a good performance in detecting glyphosate with a wider linear range from 0.05 to 100 µM, offering the detection limit of 32.0 nM for glyphosate. Additionally, S. auriculata-AuNCs are also able to visualize Saccharomyces cerevisiae cells, and successfully applied in assaying glyphosate pesticide in apple, rice, river, and canal water samples.

Dy-Al-Ce codoped silica: a promising yellow laser glass with enhanced resistance to X-ray-induced photodarkening

To develop Dy doped silica glass with a higher irradiation resistance, which can be adapted to high power violet or blue LD pumped yellow laser fibers, the designed Dy-Al-Ce codoped silica glasses, 0.05Dy2O3-1.5Al2O3-xCe2O3-(98.45-x)SiO2 (x = 0, 0.05, 0.1, 0.25, 0.5), were prepared by the sol-gel method. Their excitation spectra, emission spectra and emission decay curves associated with the yellow emission from 4F9/2 to 6H13/2 of Dy were determined before and after the X-ray irradiation of 1000 Gy. The relation between these spectra and Ce-codoping concentrations is discussed, including the sensitization from Ce to Dy, the reverse energy transfer from Dy to Ce, and especially the X-ray-induced photodarkening, which is detrimental to the 576 nm yellow emission of Dy. The centers that cause the photodarkening are analyzed by electron paramagnetic resonance and radiation induced absorption spectra. It is found that Ce can effectively suppress the Al-oxygen hole center induced by the X-ray across the entire concentration range of Ce-codoping, but a new photodarkening center is generated at higher concentrations of Ce-codoping. Finally, the optimized Ce-codoping concentration of ∼0.1 mol% is used to achieve a promising yellow laser glass of Dy-Al-Ce codoped silica with enhanced irradiation resistance, resulting in its X-ray-induced photodarkening that is only 6% - 14% of that in the Ce-undoped.

Multiphonon-coupling yellow laser in Yb:La2CaB10O19 crystal

Yellow lasers at 590 nm have many extensive applications in our daily life, but extremely difficult to attain by traditional solid-state laser technology, owing to the absence of highly-efficient transition channels at this spectral range. In this work, we proposed a cooperative lasing mechanism to obtain the yellow light emission, with multiphonon-assisted electronic transitions and phase-matched frequency-doubling. Based on the predictable configurational coordinate model, we can calculate the multiphonon-assisted emission step-by-step. Using Yb3+-doped La2CaB10O19 crystal as an example, it is capable of producing yellow laser at 581–590 nm, with a maximum output power of 4.83 W and a high slope efficiency of 31.6%. To the best of our knowledge, it represents the highest power of solid-state yellow laser realized in one single crystal pumped by a laser diode. This power scaling can be assigned to the amplified phonon-assisted emission beyond the fluorescence spectrum, and optimized crystal angle for phase-matching condition. Such a compact, low-cost, and high-power laser device, provides an alternative candidate for the spectral “yellow-gap” where no practical solid-state laser exists at present.

Electrochemiluminescence in Graphitic Carbon Nitride Decorated with Silver Nanoparticles for Dopamine Determination Using Machine Learning.

Electrochemiluminescence (ECL) luminophores with wavelength-tunable multicolor emissions are essential for multicolor ECL imaging detection and multiplexed analysis. In this work, silver nanoparticle (Ag NP)-decorated graphitic carbon nitride (g-CN@Ag) nanocomposites were synthesized. The morphology, chemical composition, structure, and ECL property of g-CN@Ag were investigated. The prepared g-CN, g-CN@Ag1, g-CN@Ag5, and g-CN@Ag10 can produce blue, blue-green, chartreuse, and yellow colored ECL emissions, respectively, by using K2S2O8 as the coreagent. The ECL emission wavelength of g-CN@Ag can be regulated from 460 to 565 nm by modulating the content of the immobilized Ag NPs. Then, a multicolor ECL detection array was fabricated by using g-CN, g-CN@Ag1, g-CN@Ag5, and g-CN@Ag10 as four ECL luminophores. Dopamine was detected based on its inhibition effect on the multicolor ECL emissions. The linear range is from 0.1 nM to 1 mM with the lowest detection limit of 44 pM. Then, machine learning-assisted multiparameter concentration prediction of dopamine was further carried out by combining the deep neural network (DNN) algorithm. This work provides a new avenue to regulate the ECL emission wavelength of g-CN by using the metal nanoparticle modification strategy and presents an effective machine learning-assisted multicolor ECL detection strategy for accurate multiparameter quantitative detection.

NIR-responsive carbon dots as an oxidative-stress amplifier and hyperthermia-induced superior photothermal in-vitro anticancer activity

A facile wet chemistry-based strategy was developed to synthesize orange emissive Carbon dots (O-CDs) based on dehydration-induced ring-fusion of the precursor (1,3-dihydroxynaphthalene) in a dehydrating sulfuric acid medium. The O-CDs revealed significant Near-infrared (808 nm) light harvesting potential with outstanding photothermal conversion efficiency (∼58%) and hence exhibited excellent NIR-light stimulated photothermal anticancer performance. Furthermore, these fluorescent O-CD nanoprobes displayed excitation-dependent polychromatic emissions in the range of 540–640 nm, with the dual emission maxima at 540 and 580 nm, corresponding to yellow and orange emission at the excitation of 490 nm. Various mitochondrial, as well as cytoplasmic apoptosis-related proteins and genes were upregulated during photothermal treatment, which suggests that hyperthermia and oxidative stress have a major impact on cell death. The anticancer activity of O-CDs is likely due to the elevated reactive oxygen species (ROS) amplification in cooperation with the hyperthermia effect. This study offers a potential alternative to bio-nanomedicine for cancer treatment by carbon-based photothermal therapy.

Achieving Near-Unity Red Light Photoluminescence in Antimony Halide Crystals via Polyhedron Regulation.

Exploration of efficient red emitting antimony hybrid halide with large Stokes shift and zero self-absorption is highly desirable due to its enormous potential for applications in solid light emitting, and active optical waveguides. However, it is still challenging and rarely reported. Herein, a series of (TMS)2SbCl5 (TMS=triphenylsulfonium cation) crystals have been prepared with diverse [SbCl5]2- configurations and distinctive emission color. Among them, cubic-phase (TMS)2SbCl5 shows bright red emission with a large Stokes shift of 312 nm. In contrast, monoclinic and orthorhombic (TMS)2SbCl5 crystals deliver efficient yellow and orange emission, respectively. Comprehensive structural investigations reveal that larger Stokes shift and longer-wavelength emission of cubic (TMS)2SbCl5 can be attributed to the larger lattice volume and longer Sb⋅⋅⋅Sb distance, which favor sufficient structural aberration freedom at excited states. Together with robust stability, (TMS)2SbCl5 crystal family has been applied as optical waveguide with ultralow loss coefficient of 3.67 ⋅ 10-4 dB μm-1, and shows superior performance in white-light emission and anti-counterfeiting. In short, our study provides a novel and fundamental perspective to structure-property-application relationship of antimony hybrid halides, which will contribute to future rational design of high-performance emissive metal halides.

Achieving Near‐Unity Red Light Photoluminescence in Antimony Halide Crystals via Polyhedron Regulation

AbstractExploration of efficient red emitting antimony hybrid halide with large Stokes shift and zero self‐absorption is highly desirable due to its enormous potential for applications in solid light emitting, and active optical waveguides. However, it is still challenging and rarely reported. Herein, a series of (TMS)2SbCl5 (TMS=triphenylsulfonium cation) crystals have been prepared with diverse [SbCl5]2− configurations and distinctive emission color. Among them, cubic‐phase (TMS)2SbCl5 shows bright red emission with a large Stokes shift of 312 nm. In contrast, monoclinic and orthorhombic (TMS)2SbCl5 crystals deliver efficient yellow and orange emission, respectively. Comprehensive structural investigations reveal that larger Stokes shift and longer‐wavelength emission of cubic (TMS)2SbCl5 can be attributed to the larger lattice volume and longer Sb⋅⋅⋅Sb distance, which favor sufficient structural aberration freedom at excited states. Together with robust stability, (TMS)2SbCl5 crystal family has been applied as optical waveguide with ultralow loss coefficient of 3.67 ⋅ 10−4 dB μm−1, and shows superior performance in white‐light emission and anti‐counterfeiting. In short, our study provides a novel and fundamental perspective to structure‐property‐application relationship of antimony hybrid halides, which will contribute to future rational design of high‐performance emissive metal halides.

Plasma-deposited reactive species assisted synthesis of colloidal zinc-oxide nanostructures

A surface-wave microwave discharge is applied to deposit reactive oxygen and nitrogen species (RONS) into the liquid subsequently used as a medium for laser ablation of a Zn metallic target. It is shown that during laser ablation in plasma-treated liquids the H2O2 concentration decreases, while in deionized water (DIW) significant H2O2 is produced. Meanwhile, the pH—initially adjusted by applying reductive metals—increases in the acidic liquids and decreases in the alkaline ones. During months of storage the pH of colloids stabilize around pH 6, which insures the long-term stability of RONS. It is demonstrated that in DIW metallic Zn NPs are created, which gradually oxidize during storage, while in the plasma-treated liquids ZnO NPs are produced with the mean size of 18 nm. In the alkaline plasma-treated liquid the NPs form large aggregates, which slows the dissolution of NPs. In the acidic and neutral solutions besides NPs nanosheets are also formed, which during storage evolve into nanosheet networks as a result of the dissolution of NPs. The band gap of the colloidal ZnO is found to decrease with the formation of aggregates and nanosheet networks. The ZnO NPs ablated in plasma-treated liquids exhibit a high-intensity visible emission covering the green-to-red spectral region. The photoluminescence spectra is dominated by the orange-red emission—previously not detected in the case of laser-ablated ZnO NPs and attributed to the interstitial Zn and oxygen sites—and the yellow emission, which can be attributed to the OH groups on the surface. It is shown that during months of storage, due to the dissolution of NPs and formation of nanosheets, the intensity of the visible emission decreases and shifts to the blue-green spectral region.

Delineating Dy3+ and Sm3+ in thermally stable strontium silicate apatites for multifunctional applications

The structural, optical and temperature dependent luminescence properties of a series of Sr2Y8-xREx(SiO4)6O2 (RE=Dy and Sm) silicate phosphors are investigated for their multifunctional applications. The phosphors were synthesized using the solid-state reaction route with varying doping levels and characterized for phase purity. X-ray Diffraction analysis revealed the hexagonal crystal structure of (Sr2RE2)(RE6)(SiO4)6O2, indicating the incorporation of rare earth (RE) ions into two distinct crystallographic sites, thereby augmenting the luminescence properties. Dy3+ doped compounds exhibit intense yellow emission, promising white light generation when paired with InGaN blue LED chips. Sm3+ doped samples show orange-red emission around 601 nm, attributed to multipole-multipole interactions, with rapid decay curves suitable for high-speed response LEDs. Correlated Color Temperature (CCT) values were computed to assess the commercial viability of these phosphors in luminescence applications and the role of lighting in the growth of indoor plants and office spaces is discussed. The Sr2Y7.8Dy0.2(SiO4)6O2 phosphor with remarkable quantum yield of 63.56% demonstrated a thermal stability of 0.27 eV with enhanced sensitivity of about 0.39% K−1 and Sr2Y7.8Sm0.2(SiO4)6O2 with stability around 0.31eV with sensitivity of 1.11% K⁻¹ at 100K reveals them as potential candidates for optical temperature sensing. These results declare the competence of synthesized novel silicate apatites in solid-state lighting and optical thermometry.

Unraveling two yellow fluorescence emission mechanisms and color-changing afterglow characteristics of Dy-doped Mg2SnO4 luminescent materials

In this work, Dy ion doped Mg2SnO4 (Mg2SnO4:Dy3+) with monochromatic yellow fluorescence and color-changing long afterglow properties are prepared by the high-temperature solid-phase method. Mg2SnO4:Dy3+ shows the best luminescence performance under the preparation conditions of 1550 °C and 0.02 Dy3+ concentration. The samples are able to achieve yellow fluorescence emission (λem = 575 nm) under 350 nm and 291 nm excitation, and the emission intensity of the samples under 350 nm excitation is much higher than that of 291 nm excitation. Under 254 nm excitation, the sample not only emits bright white fluorescence but also has the ability of obvious afterglow after excitation. Moreover, the afterglow also has the color change function of transition from bright white to yellow. The luminescence mechanism study shows that Mg2SnO4:Dy3+ contains two emission centers, Dy3+ and lattice defects. Combining the results of spectroscopic measurements with the Dy3+ energy level distribution data, two different fluorescence emission processes under 291 and 350 nm excitation as well as the afterglow discoloration mechanism due to 254 nm excitation are discussed in detail.

Investigation on spontaneous recombination mechanisms in GaN based laser diodes under low injection current

This study works on the spontaneous recombination mechanisms of GaN-based laser diodes (LDs) under low injection current by examining their power–current (P–I) curves and electroluminescence spectra. Our investigation focuses on the behavior of differential efficiency in LDs under low injection current, revealing that a competition between impurity-related yellow emissions and band-edge blue emissions leads to a change in total luminescence efficiency. Using both experimental and simulating methods, the yellow emission peak is primarily attributed to carrier recombination in deep-level defects located on the LD's p-side. A detailed explanation to the differential efficiency changing mechanism is beneficial to improve the GaN-based LD performance in future fabrication.

Multifunctional BNT-based ferroelectric ceramics with large electrostrain and strong photoluminescence properties

The development of multifunctional materials with optical and electrical properties has become a research hotspot in recent years. In this work, multifunctional 0.935(Bi[Formula: see text]Na[Formula: see text])TiO3–0.065BaTiO3 (BNT–BT)-based ferroelectric ceramics doped with small amounts of CaMAlO4 ([Formula: see text], Ho) were prepared, and the effect of CaMAlO4 on the electrostrain and photoluminescence properties of the ceramics was studied. The results showed that the CaMAlO4 addition weakened the ferroelectric properties of the BNT–BT matrix, and promoted the improvement of the electrostrain performance. For samples doped with 1.5[Formula: see text]mol% CaMAlO4, the unipolar strain [Formula: see text] reached the largest values, which were 0.33% ([Formula: see text]) and 0.38% ([Formula: see text]) under an electric field of 70[Formula: see text]kV/cm, corresponding to a large signal [Formula: see text] ([Formula: see text]) of 471[Formula: see text]pm/V ([Formula: see text]) and 543[Formula: see text]pm/V ([Formula: see text]), respectively. In addition, due to the existing Dy[Formula: see text] and Ho[Formula: see text] luminescent ions, the modified samples exhibited excellent photoluminescence performance, which exhibited bright yellow emission ([Formula: see text]) and green emission [Formula: see text] under the blue excitation. Due to their multifunctional features, these materials have potential applications as “on-off” actuators, optical-electro integration and coupling devices.

HfTiO4 transparent thick film phosphors activated with Eu3+, Dy3+, and Tb3+ ions

Hafnium (Hf)-based double oxides show promise as high-efficiency scintillators due to large effective atomic numbers and high relative density. However, the preparation of these scintillation crystals is challenging due to their high melting points and incongruent melting behavior. In the present study, we demonstrated that the chemical vapor deposition (CVD) of single-phase HfTiO4 films on quartz glass substrate was successfully deposited at temperatures ranging from 973 to 988 K, with a TiO2 molar ratio in the precursor vapor of 25–45 mol% TiO2. The deposition rate of HfTiO4 reached 36 µm h−1. The films exhibited an in-line transmittance of 78 % relative to the raw glass substrate at a wavelength of 600 nm. When activated with Eu3+, Dy3+, and Tb3+ ions, the HfTiO4 films displayed red, yellow, and green photoluminescence emissions originated from the 4f–4f transitions of each trivalent rare-earth ion under ultraviolet light irradiation. HfTiO4 exhibited no intrinsic background emission, suggesting that the addition of a selected activator could yield a phosphor with the desired emission color range.

Photoluminescence properties of Pb5(PO4)3Br:RE (RE = Dy3+, Eu3+ and Tb3+) phosphor synthesised using solid-state method.

This study describes the luminous properties of Pb5(PO4)3Br doped with RE3+ (RE = Dy3+, Eu3+ and Tb3+) synthesised using the solid-state method. The synthesised phosphor was characterised using Fourier-transform infrared, X-ray diffraction, scanning electron microscopy and photoluminescence measurements. Dy3+-doped Pb5(PO4)3Br phosphor exhibited blue and yellow emissions at 480 and 573 nm, respectively, on excitation at 388 nm. Eu3+-doped Pb5(PO4)3Br phosphor exhibited orange and red emissions at 591 and 614 nm, respectively, on excitation at λex = 396 nm. Pb5(PO4)3Br:Tb3+ phosphor exhibited the strongest green emission at 547 nm on excitation at λex = 380 nm. Additionally, the effect of the concentration of rare-earth ions on the emission intensity of Pb5(PO4)3Br:RE3+ (RE3+ = Dy3+, Eu3+ and Tb3+) phosphors was investigated.

Metal-organic frame material encapsulated Rhodamine 6G: A highly sensitive fluorescence sensing platform for the detection of picric acid contaminants in water

As a water pollutant with excellent solubility, 2,4,6-trinitrophenol (also known as picric acid, PA) poses a potential threat to the natural environment and human health, so it is crucial important to detect PA in water. In this study, a novel composite material (MIL-53(Al)@R6G) was successfully synthesized by encapsulating Rhodamine 6G into a metal-organic frame material, which was used for fluorescence detection of picric acid (PA) in water. The composite exhibits bright yellow fluorescence emission with a fluorescence quantum yield of 58.23 %. In the process of PA detection, the composite has excellent selectivity and anti-interference performance, and PA can significantly quench the fluorescence intensity of MIL-53(Al)@R6G. MIL-53(Al)@R6G has the advantages of fast detection time (20 s), wide linear range (1–100 µM) and low detection limit (4.8 nM). In addition, MIL-53(Al)@R6G has demonstrated its potential for the detection of PA in environmental water samples with satisfactory results.

Multistimuli-responsive tetraphenylethene molecular switches displaying acid-sensing, photochromism, and metal ion detection properties

Aggregation-induced emission (AIE) smart materials with multiple stimulus responses have a wide range of applications. Here, a series of tetraphenylethylene (TPE) derivatives, TPEN1S3, TPEN2S2, TPEN3S1 were synthesized. The sensitivity of molecules to pH, UV light, and metal ions could be effectively tuned by modulating the ratio of amino to sulfonic acid groups. These TPE derivatives exhibited yellow emissions in aggregated state due to the AIE characteristics. Acidification conversion of the NH2 groups to NH3+ for three molecules induced the suppression of intramolecular charge transfer (ICT), which resulted in a 72–102 nm blue shift in the fluorescence emission. Solid powders of these compounds exhibited reversible protonation-deprotonation process induced by HCl/NH3·H2O vapor. TPEN1S3, TPEN2S2 and TPEN3S1 in solution could be photoactivated and emit blue fluorescence (ca. 482 nm, 475 nm, and 480 nm). Photocyclo-dehydrogenation reactions of compounds were triggered by the UV irradiation and the maximum cyclization ratios could reach 12%, 66%, and 50%, respectively. Protonation of NH2 group significantly enhanced the rate of the photocyclo-dehydrogenation reaction. Furthermore, the solid powders of protonated compounds displayed pronounced reversible photochromic properties due to the generation of cyclization intermediate. In addition, TPEN1S3, TPEN2S2, and TPEN3S1 exhibited responsiveness to a diverse range of metal ions. Specifically, the TPEN2S2 molecule functioned as a photo sensor for Li + ions with a blue shift in fluorescence emission. The limit of detection (LOD) value was 0.679 μM. These multiple stimuli-responsive AIE molecules hold significant potential for use in advanced photo-controlled patterning, encryption applications, and the detection of metal ions.

Lead-free CsCu2I3 thin films prepared by one-step chemical vapor deposition method for ultraviolet photodetector

In recent years, inorganic lead-free perovskite materials have garnered attention for their non-toxicity, high carrier mobility, and strong light absorption capabilities, showing promising application prospects in photoelectric sensing. CsCu2I3 perovskite has been mentioned as one of the representatives and as a potential material for short-wavelength optoelectronic devices. This study employs a one-step chemical vapor deposition (CVD) process to fabricate CsCu2I3 thin films, which exhibit a vibrant yellow emission at 560 nm. Ultraviolet photodetectors utilizing CsCu2I3 films demonstrate an exceptional responsivity and a detectivity of 1.43 A/W and 1.15 × 1012 Jones (254 nm, 5 V bias), along with rapid response times (trise ≈ 50 ms, tdecay ≈ 70 ms). Moreover, this work examines the factors affecting device performance, including wavelength, operating voltage, and film thickness. It presents a straightforward, ecofriendly CVD method for producing lead-free perovskite films and optoelectronic devices, which has significant implications for the development of lead-free perovskite-based photoelectric technologies.