LED Chip Research Articles

Luminescent CdS quantum dot-embedded glass for W-LED lighting and X-ray imaging

Quasi-zero-dimensional quantum dots (QDs) have garnered significant attention owing to their distinct structural attributes, quantum confinement behaviors, optoelectronic characteristics, etc. Regrettably, their susceptibility to stability poses a challenge. In this context, leveraging rational component regulation and crystallization process optimization strategies, we presented the successful preparation of CdS QDs silicate glass through the amalgamation of melt-quenching and controlled crystallization. The optical and morphological analysis substantiated the accomplishment of in-situ precipitation of CdS QDs within the glass matrix, with grain sizes <20 nm. Integrating CdS QDs into an inorganic glass matrix remarkably augmented its fluorescence thermal stability, enabling the preservation of 85.1 % of the room-temperature luminescent intensity even at an elevated temperature of 150 °C. Moreover, the encapsulated W-LED device by near-UV LED chip, CdS QDs glass, and BaMgAl10O17:Eu2+ phosphor exhibited a warm white-light emission characterized by suitable chromaticity coordinates (0.3741, 0.3452) and a notably high color rendering index (CRI = 93). Ultimately, the radioluminescence behavior of CdS QDs glass was unveiled by utilizing it as the scintillator wafer in an X-ray imaging system, which clearly demonstrated the structure of spring encapsulated within an opaque capsule. In a nutshell, these demonstrations unequivocally emphasize the substantial potential merits of CdS QDs glass, particularly in the domains of long-term W-LED lighting and X-ray imaging applications.

Blue-emitting Bi3+-doped K2MGeO5 (M = Hf, Zr) phosphors for full-spectrum WLED: Crystal structure, electronic structure and luminescent properties

Developing efficient and stable blue-emitting phosphors has always been crucial for advancing full-spectrum WLED technology. In this study, the germanates K2MGeO5 (M = Zr, Hf) were chosen as the host to develop novel NUV-excited blue-emitting phosphors. The crystal structure, electronic structure, and luminescence properties of K2MGeO5:Bi3+ were comprehensively investigated using X-ray powder diffraction, Rietveld refinement, photoluminescent spectra analysis, and density functional theory calculations. By integrating experimental data with semi-empirical formula calculations, the excitation and emission sources were elucidated. Furthermore, the influence of Bi3+'s local coordination environment on its luminescence performance and the concentration quenching mechanism in K2MGeO5:Bi3+ were thoroughly examined. A full-spectrum WLED was fabricated by synergistically combining K2ZrGeO5:Bi3+, commercially available green and red phosphors with a 365 nm LED chip. It is anticipated that this study could provide insights for the advancement of blue phosphors excited by near-ultraviolet light.

Ring geometric effect on the performance of AlGaN-based deep-ultraviolet light-emitting diodes.

In this study, we fabricated and characterized various parallel flip-chip AlGaN-based deep-ultraviolet (DUV) micro-ring LEDs, including changes in ring dimensions as well as the p-GaN-removed region widths at the outer micro-ring, respectively (PRM LEDs). It is revealed that the LED chips with smaller mesa withstand higher current density and deliver considerably higher light output power density (LOPD), under the same proportion of the hole to the entire mesa column (before it is etched into ring) within the limits of dimensions. However, as the ring-shaped mesa decreases, the LOPD begins to decline because of etching damage. Subsequently, at the same external diameter, the optical performance of micro-ring LEDs with varied internal diameters is studied. Meanwhile, the influence of different structures on light extraction efficiency (LEE) is studied by employing a two-dimensional (2D)-finite-difference time-domain (FDTD) method. In addition, the expand of the p-GaN-removed region at the outer micro-ring as well as the corresponding effective light emission region have some influence to LOPD. The PRM-23 LED (with an external diameter of 90 µm, an internal diameter of 22 µm, and a p-GaN-removed region width of 8 µm) has an LOPD of 53.36 W/cm2 with a current density of 650 A/cm2, and an external quantum efficiency (EQE) of 6.17% at 5 A/cm2. These experimental observations provide a comprehensive understanding of the optical and electrical performance of DUV micro-LEDs for future applications.

A promising yellow-emitting langbeinite-type phosphor NaBaY2(PO4)3:Eu2+ for WLEDs.

The development of novel phosphors with excellent luminescence properties for white light-emitting diodes (WLEDs) is always a formidable task. Compared with the traditional laborious and aimless "trial and error" experiments, a mineral-inspired prototype strategy can provide an efficient and accurate method. Herein, for the first time, a novel yellow-emitting phosphor NaBaY2(PO4)3:Eu2+ was discovered using the mineral-inspired prototype strategy and cation substitution method. The phosphor was prepared via the high-temperature solid-state reaction method, and its crystal structure, luminescence properties and potential application for WLEDs were systematically investigated. The NaBaY2(PO4)3 phase was derived from the K2Mg2(SO4)3-type mineral structure and a photoluminescence study revealed that the phosphor can emit bright yellow light with a maximum at 545 nm upon excitation at 351 nm. A WLED lamp was fabricated by the use of a blend of commercial blue-emitting BaMgAl10O17:Eu2+, yellow-emitting NaBaY2(PO4)3:Eu2+ and red-emitting (Ca, Sr)AlSiN3:Eu2+ phosphors with a 380 nm LED chip. The CIE, CCT, Ra and efficiency of the as-fabricated LEDs were measured to be equal to (0.366, 0.365), 4327 K, 91.2 and 40.8 lm W-1, respectively. These results suggest that NaBaY2(PO4)3:Eu2+ could be a promising candidate for n-UV WLEDs.

A highly efficient deep red-emitting Mn4+-powered oxyfluoride nanophosphor developed for plant growth and optical thermometric applications.

This research mainly highlighted an intense deep red-emitting and Mn4+-powered oxyfluoride nanophosphor, Mg14Ge4.99O16F8:0.01Mn4+ (MGOF:Mn), which was synthesized via adopting a scalable synthesis route for commercial temperature sensing and artificial plant growth applications. The electron microscopic analysis confirmed the formation of nanosized particles without any defined shape or size distribution. The obtained nanophosphor exhibited sharp emission peaks at 659 nm and 631 nm under UV (317 nm) and blue excitation (417 nm) owing to Mn4+:2Eg → 4A2g and Mn4+:2T1g → 4A2g transitions, respectively. The emission spectrum is situated in the deep red region of the CIE color diagram where the red color purity approached 100% under both the excitations. The absorption efficiency and the internal and external quantum efficiencies of this red-emitting system were calculated to be 53%, ∼77%, and ∼41%, respectively, under blue excitation of 417 nm, which indicated its potential for indoor plant cultivation. A prototype red LED was fabricated by pasting the red-emitting MGOF:Mn4+ nanophosphor powder on a 410 nm blue LED chip. The resulting electroluminescence spectrum overlapped with those of the important organic pigments of normal plants. Importantly, the thermometric properties of the nanophosphor were evaluated in detail for FIR and lifetime-based thermometry applications. The examined nanophosphor showed an extreme absolute sensitivity of 0.00326 K-1 at 373 K with excellent reproducibility and temperature resolution. Because of the small particle size and high luminescence efficiency, the nanophosphor could be implemented in various nano-devices where non-contact optical thermometry is necessary for high performance.

Broadband near-infrared luminescence in a cubic pyrophosphate Al0.5Ta0.5P2O7:Cr3+ phosphor for multi-functional applications.

Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are considered as next-generation of NIR light sources for spectroscopy. However, it is still a challenge to develop an inexpensive broadband NIR phosphor with relatively long-wavelength (λem > 800 nm) emission. In this work, an octahedral Al3+-containing pyrophosphate Al0.5Ta0.5P2O7 with a cubic structure was chosen as a host for Cr3+. Synthesizing this material indicates that this phosphor exhibits a broadband NIR emission peaking at 850 nm with a full width at half maximum (FWHM) of 155 nm under 465 nm excitation. The crystal structure, morphology, local structure, and photoluminescence properties of this material were investigated in detail. The results revealed a full understanding of this new material. A NIR pc-LED device fabricated by using this material combined with a 450 nm LED chip generates a NIR output power of 10.7 mW and a NIR photoelectric conversion efficiency of 3.4% under a 100 mA driving current, which shows the possibility of this material to be utilized in NIR pc-LED applications. Moreover, this material exhibits a linear relationship between emission intensity, decay time and temperature in a wide temperature range, implying that excellent multi-model temperature sensing applications can be expected.

Barium molybdate up-conversion nanoscale particles with IR-LED chip, temperature sensing, and anti-counterfeiting applications.

Barium molybdate nanoparticles exhibiting up-conversion luminescence were synthesized via the solvothermal method. Analysis revealed a prominent signal corresponding to the (112) plane in the XRD pattern, indicating the tetragonal structure of the synthesized nanoparticles. Raman spectroscopy detected the symmetric stretching frequencies of MoO4. When excited at 980 nm, the nanoparticles emitted a green spectrum with peaks at 532 and 553 nm. The luminescence intensity varied with the excitation light source, supporting the mechanism involving energy transfer from Yb-doped Er ions via the two-photon effect of the up-conversion phosphor. Moreover, the synthesized nanoparticles exhibited diminished luminous intensity with increasing temperature, suggesting potential for flexible composite sensor fabrication. Integration with a 980 nm LED chip yielded a green emission color. Furthermore, when applied to banknotes, plastic cards, fabrics, and artwork, the opaque solution mixed with polymers remained invisible to the naked eye; however, under 980 nm laser irradiation, the distinct green color became apparent, offering a viable approach for anti-counterfeiting measures.

Structure modification and luminescence regulation in new violet light excitable Sr(2-y)BayY4La4(SiO4)6O2:xEu2+ phosphors via cation substitution.

Cyan-emitting phosphors are urgently needed to address the "cyan gap" in artificial full-spectrum lighting. In this research, a series of Sr(2-y)BayY4La4(SiO4)6O2:xEu2+ (0.005 ≤ x ≤ 0.08, 0.0 ≤ y ≤ 2.0) phosphors with tunable luminescence was synthesized. Through cation regulation, the luminescence color of Sr(2-y)BayY4La4(SiO4)6O2:xEu2+ can be adjusted from yellow to cyan. Crystal structure analysis revealed that Eu2+ ions simultaneously occupy [Sr1/Ba1Y1La1] and [Sr2/Ba2Y2La2] sites, resulting in multiple luminescence centers and a broadened emission spectrum. With increasing Ba2+ ion concentration, the PLE spectrum was red-shifted from 337 nm to 372 nm, and the excitation intensity in the violet region was significantly enhanced, making it more compatible with violet LED chips. Meanwhile, the PL spectrum was blue-shifted from 543 nm to 496 nm with increasing Ba2+ concentration, accompanied by an increase of about 10 times in the excitation and emission intensity. The optimized Ba2Y4La4(SiO4)6O2:0.02Eu2+ phosphor can be excited by violet light and emits bright cyan light effectively, which can be used to fill the "cyan gap". Eventually, a series of white LED devices was manufactured by combining the as-prepared luminescence-tunable phosphors with commercial phosphors. Among them, the 410 nm violet LED chip-based WLED(Ba2) device comprising Ba2Y4La4(SiO4)6O2:0.02Eu2+ exhibited the best electroluminescence performance, increasing the color rendering index from 82.0 to 98.6, verifying the compensation effect of the Ba2Y4La4(SiO4)6O2:Eu2+ phosphor on cyan light.

Broadband Ca3MgZrGe3O12:Cr3+ garnet phosphor for high-performance NIR pc-LED application.

The near-infrared (NIR) phosphor-converted light-emitting diode (pc-LED) is heavily reliant upon the performance of NIR phosphors. However, the current NIR pc-LEDs suffer from low photoelectric efficiency and insufficient near-infrared output power. In this study, Cr3+-doped Ca3MgZrGe3O12 phosphors leading to high-performance NIR pc-LEDs were developed for the first time. They feature robust and wide NIR emission that extends over the spectrum from 650 to 1100 nm with a full width at half maximum of 120 nm, a high quantum yield of 82% and excellent thermal stability of T50% = 250 °C and I150 °C = 80% when excited at 460 nm. The NIR pc-LED was constructed by combining the Ca3MgZrGe3O12:0.04Cr3+ phosphor with a blue LED chip, resulting in a device that exhibits a photoelectric conversion efficiency of 20% and a near-infrared output power of 54.19 mW when operated at a current of 100 mA. The obtained luminous efficacy is superior to that of the vast majority of current broadband near-infrared pc-LEDs. In addition, this NIR pc-LED exhibits strong penetration and its applications in bio-imaging are demonstrated. The results indicate that Ca3MgZrGe3O12:Cr3+ NIR broadband phosphors are efficient for NIR pc-LEDs.

Highly thermostable RhB@Zr-Eddc for the selective sensing of nitrofurazone and efficient white light emitting diode.

Highly thermostable RhB@Zr-Eddc composites with the Rhodamine B (RhB) enclosed into the nanocages of Zr-Eddc was synthesized by one-pot method under hydrothermal conditions, whose structure, morphology and stability were characterized through the X-ray powder diffractometry (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). RhB@Zr-Eddc showed the highly thermal stability up to 550°C and emitted the bright red-light emission at 605nm, which could highly selective detect the nitrofurazone (NFZ) among eleven other antibiotics in aqueous solution. Furthermore, via combining the RhB@Zr-Eddc with commercial green phosphor (Y3Al5O12:Ce3+, Ga3+), the mixture was encapsulated onto a 455nm blue LED chip, creating an ex-cellent white light emitting diode (WLED) device with the correlated colour temperature (CCT) of 4710K, luminous efficiency (LE) of 43.17lm/w and Color Rendering Index (CRI) of 89.2.

A novel blue emitting phosphor Ca1-ySryScBO4:Bi3+ with zero-thermal quenching for multi-scenario application.

In recent years, Bi3+ activated phosphors have received a lot of attention from researchers; however, the performance and application areas of phosphors are yet to be developed. In this work, a series of CaScBO4(CSBO):xBi3+ phosphors were successfully prepared using a high-temperature solid-state method. Under UV excitation, blue light emission was achieved at 430 nm with a quantum yield of 91%, and at 423 K, the emission intensity retained 82.8% of the original intensity at 298 K. By crystal field engineering, the substitution of Sr2+ at the Ca2+ site enhances the temperature stability of the material, and at 423 K, 473 K and 573 K, the samples maintain 104%, 103% and 85% of the emission intensity at room temperature, respectively. It indicates that the cation substitution causes the increase in the oxygen vacancy concentration, and the oxygen vacancy defect compensates the energy lost in electrons at high temperature, producing resistance to anti-TQ performance. Finally, a blue-violet LED was fabricated by using the phosphor and an ultraviolet LED chip, and white LEDs (CCT = 4683 K, Ra = 89.7) were obtained by co-packaging this phosphor with commercial phosphors and a UV chip. Importantly, the great potential of this phosphor in the field of plant lighting and biocontrol can be demonstrated.

Structure and optical properties of stable Bi/Eu codoped borophosphate La7O6(BO3)(PO4)2 phosphors for application in wLEDs

Rare-earth (RE) and/or transition metal (TM) ions (co)doped phosphors have garnered much attention for promoting development in the fields of solid state lighting (SSL) and displays. It is a meaningful work to design high-quality phosphor via intelligent assembling from wide variety of compounds with RE/TM ions. Herein, the lanthanum borophosphate La7O6(BO3)(PO4)2 (LOBP) and Bi/Eu were selected as host and dopants for constructing the phosphor LOBP: Bi/Eu via solid phase synthetic method due to simple synthesis, chemical/thermal stability, rich cationic sites, appropriate bandgap, and controllable optical tuning from synergistic effect of cyan (Bi) and red (Eu) emissions, respectively. The structure and site occupations were analysed via XRD and Rietveld refinements, showing Bi3+ ions were only resided in La3+ sites within the monoclinic matrix (P21/n) and appeared greater inclination towards the La sites with coordinate number (CN) = 8 as compared with CN = 7 due to the closer ion radius ratio. While Eu3+ ions entered into the two distinct La sites with almost the same probability. The morphology and elemental mapping were obtained via SEM/EDS, exhibiting irregular particle shape with micron-level size, and the chemical composition met expectation. Through energy transfer (ET) from Bi to Eu under n-UV excitation, the adjustable photoluminescence (PL) from cyan traversing white and finally to red could be achieved. The concentration quenching for both singly- (Bi) and co-doped (Bi/Eu) phosphors were charged by the d-d interactions. Finally, the stable as-fabricated n-UV pumped wLED via coupling the composition-optimized white-emitting LOBP: 2%Bi, 7%Eu to a commercial 305 nm n-UV LED chip shows splendid performances.

A novel Eu3+ activated Ca3Zn3Te2O12 tellurate red phosphor for white LEDs with high color stability and color purity

Research into red phosphors with a high color rendering index is particularly compelling, given the absence of a red component in the spectrum of commercial pc-WLEDs, which combine blue LED chips with yellow-emitting YAG:Ce3+ phosphors.

Design and Analysis of LED-Based Artificial Plant-Growing Fixture for Vertical Indoor Farming Systems

The ability to perform photosynthesis with artificial lighting has eliminated the dependence on the sun in the agricultural industry. With the elimination of dependence on the sun, indoor plant production has been enabled by using artificial lighting in facilities such as vertical farming facilities. As a result of making soilless agriculture possible in vertical farming facilities, more organic and healthier plant production can be achieved as the plant is free from diseases and pests and therefore there is no need for pesticides. At the same time, thanks to the facilities to be established in city centers, the access process and cost of the plants grown will be reduced. In this study, the light needed for the growth of plants in the indoor vertical soilless agriculture facility was artificially designed using LED chips. In the luminaire(fixture) design, the wavelength and level of light can be adjusted according to the needs of plant growth periods. Comparative analyzes were made of the LED-based internal vertical luminaire design results carried out within the scope of the study and equivalent products used for the same purpose.

Influence of substrate size and gas on thermal and optical performance of LED filament bulbs

LED filament lamp with high brightness, low power consumption and long life, is a new generation of LED lighting new light source. Although the high-density integration of LED chips into the substrate can provide more functionality, but the LED filament heat dissipation performance aspects is a major problem affecting the luminous efficiency and reliability. Here, the LED chips were solid-crystallized onto 1.5 mm and 3.0 mm ceramic substrates, and the effects of substrate size and filling gas on the heat dissipation and optical performance of the filament lamps were investigated by finite element analysis (FEA). The heat distribution, luminous flux and luminous efficiency of the bulb surface were analyzed. The simulation results show that filling helium has better heat dissipation and optical performance than filling nitrogen or air, and the average junction temperature of the LED filament decreases from 119.28 °C to 105.40 °C, the luminous flux increases from 551.66 lm to 583.38 lm, and the luminous efficacy increases from 142.5 lm/W to 151.1 lm/W when the substrate size is changed from 1.5 mm to 3.0 mm. It can be seen that increasing the size of the substrate, LED filament lamp heat dissipation effect and optical performance is better. Experimental tests also support the simulation results. The results provide guidance for the thermal design of high-power LED filament bulbs.

Small Stokes Shift and Two‐Site Occupation in the ANb2O6:Cr3+ (A = Zn/Mg) Phosphors Toward Highly Efficient Ultra‐Broadband Near‐Infrared Emission for Multifunctional Applications

AbstractThe development of the new generation of smart near infrared (NIR) light sources is a problem demanding prompt solution with the increasing role of NIR spectroscopy in security, food, medical treatment, agriculture, and other fields. In this work, Cr3+ doped ANb2O6 (A = Zn/Mg) phosphors are successfully developed, which generate a NIR emission with a peak at 930 nm covering 750–1300 nm under excitation of 515 nm light. Thanks to the small Stokes shift, the internal quantum efficiency (IQE) values of the optimal samples of ZnNb2O6:Cr3+ and MgNb2O6:Cr3+ reach up to 70% and 62%, respectively. This ultra‐broadband NIR emission originates from the simultaneous occupation of [AO6] and [NbO6] octahedrons by Cr3+, which is confirmed by the excitation wavelength‐dependent emission spectra, low‐temperature photoluminescence spectra (77 K), time‐resolved photoluminescence (TRPL) spectra, and density functional theory (DFT) calculation. The thermal quenching mechanism of ANb2O6:Cr3+ (A = Zn/Mg) is revealed from the aspects of thermal cross and thermal ionization. Benefiting from the excellent performance of ANb2O6:Cr3+ (A = Zn/Mg) NIR phosphors, the combination of 520 nm LED chips, and as‐prepared phosphors demonstrate the dramatic potential applications in night vision, non‐destructive testing, biological tissue imaging, and spectral analysis.

Broadband Near-Infrared Sr3Al9.8SiO20:0.2Cr Phosphor Realized by Crystallographic Site Engineering.

Broadband near-infrared (NIR) phosphor-converted devices play a vital role in emerging applications of imaging, medicine, agriculture, etc. Herein, a series of economical broadband NIR-emitting Sr3Al10-xSiO20:xCr (SASO:xCr) phosphors with tunable bandwidths and emission peaks were realized by tailoring the Cr3+ doping concentration. The optimal Sr3Al9.8SiO20:0.2Cr (SASO:0.2Cr) phosphor exhibits a broadband emission with full width at half-maximum ∼ 140 nm, and the internal/external quantum efficiency and thermal stability of the SASO:0.2Cr were measured to be 68%/37% and 77%@380 K, respectively. An NIR phosphor-converted light-emitting diode (NIR pc-LED) device was fabricated by combining a blue LED chip with the SASO:0.2Cr phosphor. The applications of NIR pc-LED on plant growth promotion, night vision, and medical imaging were demonstrated. We reported an economical broadband NIR phosphor with multiple potential applications and highlighted the crystallographic site engineering strategy to explore broadband phosphors based on aluminates.

High external quantum yield in near-infrared phosphor Bi2Ga4O9:Cr3+ excited by near-ultraviolet or blue light

The proliferation of portable and intelligent devices featuring Near-Infrared (NIR) light sources as a central component has resulted in a significant need for compact NIR light sources. The technique of NIR phosphor-converted light-emitting diodes (NIR-pc-LEDs) could offer a fresh viewpoint on NIR light sources. The performance of NIR-pc-LEDs is directly influenced by NIR phosphors. However, the development of NIR phosphors with high external quantum yield (EQY) NIR phosphors has been hampered. In this work, we report a mullite-structure NIR phosphor, Bi2Ga4O9: Cr3+ (BGO), which exhibits excellent NIR luminescence properties. The emission spectrum of the optimal doped sample BGO:0.06Cr3+ has two emission peaks at 711 and 763 nm. All samples can be efficiently excited by commercial 365 nm near-ultraviolet LED chips and 450 nm blue LED chips. The internal quantum yield (IQY) reaches an astonishing value of 89.13 % and an EQY of about 65.36 % at 365 nm excitation. Furthermore, BGO:0.06Cr3+ shows a high IQY (∼87.78 %) and EQY (∼41.64 %) upon 450 nm excitation. Moreover, concerning thermal stability, the integrated photoluminescence intensity remains at 82 % and 42 % of that at room temperature when measured at 373 K and 423 K, respectively. The capsuled NIR-pc-LED device can be utilized for blood veins imaging, food safety analysis, and information encryption. These results highlight the promising commercial prospects of BGO:0.06Cr3+ in the fields of bio-imaging and non-destructive testing, among others.

Engineering deep-red Al20B4O36:Cr3+ phosphors for photomorphogenesis

Cr3+ doped phosphors with deep-red luminescence hold great promise as artificial lighting sources for plants growth. Among them, α-Al2O3:Cr3+ is featured with an ultra-intense pure zero phonon line (ZPL) emission with negligible sidebands. Nonetheless, further enhancements in its luminescence thermal stability are required to fully unlock its potential for practical applications. To tackle this challenge, we propose that Al20B4O36 with a negative expansion coefficient could serve as a more favorable host materials for Cr3+ ion, thereby enhancing the luminescence thermal stability. Our first-principles calculations have unveiled similar electronic structures for α-Al2O3:Cr3+ and Al20B4O36:Cr3+, suggesting that the observed zero phonon R-line (2Eg) emission, arising from the 2Eg→4A2g transition in α-Al2O3:Cr3+, might also be present in Al20B4O36:Cr3+. Based on these findings, we prepared Al20B4O36:Cr3+ phosphors using a simple solid reaction method and confirmed that Al20B4O36:Cr3+ indeed exhibits a similar ultra-intense pure ZPL emission centered at 694 nm. Moreover, Al20B4O36:Cr3+ phosphors demonstrate remarkable properties including a high internal quantum efficiency (IQE) of 98.2 % and superior luminescence thermal stability compared to α-Al2O3:Cr3+. A phosphor converted light emitting diode (pc-LED) is developed by coating Al20B4O36:Cr3+ phosphor onto a near-ultraviolet LED chip. The lighting from this deep-red LED significantly impacts the photomorphogenesis of bean sprouts. Our study showcases a rational approach to design novel Cr3+ doped phosphors with enhanced luminescent properties, tailored for specific applications.

Highly luminescent heteroatom codoped carbon dots for multitudinous applications

Carbonaceous nanomaterials have shown great potential in the analytical and environmental domains due to their natural intriguing properties. Rich in quantum yield and reliable performances are necessary for carbon dots to be effectively used in the real-world applications. Carbon dots (CDs) exhibits high blue-emission with a quantum yield (ϕ) of 11% were synthesized through a single-step superficial pyrolysis technique. In this work, the derived carbon dots were employed as reducing and stabilizing agents in a unique one-step approach for the synthesis of AgNPs. The fluorescence of CDs was found to be quenched in the presence of dopamine with greater sensitivity, the minimum limit of detection was determined as 0.35 μM and possible mechanism could be the inner filter effect along with photoinduced electron transfer. In addition to this, the outstanding optical properties of CDs enable them to use as invisible ink in loading secret information and provide enhanced counterfeit protection. The solid-state quenching is successfully prevented when the CDs were dispersed in a polymer matrix for solid-state films preparation. The CDs-polymer composite is packed on top of a 365 nm UV LED chip, which emits blue light, to fabricate blue LED. Hence, we suggest that the synthesized CDs may serve as a future trend setter by as a single molecular probe for multifarious applications such as optoelectronics and forensic fields. Previously, we utilized these CDs for fingerprint detection and now apply them for new emerging applications.