Cyan Emission Research Articles

Improved thermal stability and quantum efficiency of novel cyan phosphors toward full-visible-spectrum lighting

Highly efficient cyan phosphors have been identified as essential components in addressing the cyan gap present in the emission spectra of traditional white light emitting diodes. Here, we report novel Ba4Ca1-yLay(PO4)3Cl:Eu2+ (y = 0–0.15) phosphors with broadband cyan emission based on an efficient and positive cationic heterovalent substitution strategy. Under the near ultraviolet excitation, the quantum yield and thermal stability are progressively enhanced by introducing La3+ to replace the Ca2+ ions, owing to the band gap and killer centers engineering. The Ba3.92Ca0.9La0.1(PO4)3Cl:0.08Eu2+ phosphor exhibits a pronounced emission band in the cyan-green spectral range with a high internal quantum efficiency of 88.0% and an impressive external quantum efficiency of 72.1%. The utilization of Ba3.92Ca0.9La0.1(PO4)3Cl:0.08Eu2+ as the cyan emitting component in the fabrication of white light-emitting diode (WLED) has demonstrated remarkable advancements in the color rendering index value, emphasizing the potential of these phosphors for future implementation in the next generation full-visible-spectrum WLED lighting. Our findings offer evidences that defect engineering techniques effectively enhance the performance of light-emitting diode (LED) phosphors.

The developments of cyan emitting phosphors to fulfill the cyan emission gap of white-LEDs.

Future generations of solid-state lighting (SSL) will prioritize the development of innovative luminescent materials with superior characteristics. The phosphors converted into white light-emitting diodes (white LEDs) often have a blue-green cavity. Cyan-emitting phosphor fills the spectral gap and produces "full-visible-spectrum lighting." Full-visible spectrum lighting is beneficial for several purposes, such as light therapy, plant growth, and promoting an active and healthy lifestyle. The design of cyan garnet-type phosphors, like Ca2LuHf2Al3O12 (CLHAO), has recently been the subject of interest. This review study reports a useful cyan-emitting phosphor based on CLHAO composition with a garnet structure to have a cyan-to-green emitting color with good energy transfer. It could be employed as cyan filler in warm-white LED manufacturing. Due to its stability, ability to dope with various ions suitable for their desired qualities, and ease of synthesis, this garnet-like compound is a great host material for rare-earth ions. The development of CLHAO cyan-emitting phosphors has exceptionally high luminescence, resulting in high CRI and warm-white LEDs, making them a viable desire for LED manufacturing. The development of CLHAO cyan-emitting phosphors with diverse synthesis techniques, along with their properties and applications in white LEDs, are extensively covered in this review paper.

Regulation of Anti‐Thermal Quenching and Emission Color in Eu2+‐Activated Na‐Beta‐Alumina Phosphors for Full‐Spectrum Illumination

AbstractBroadband cyan‐emitting phosphors are crucial to close the cyan gap of phosphor‐converted white light‐emitting diodes (pc‐WLEDs) for full‐spectrum illumination. In this work, efficient cyan‐emitting Eu2+‐activated phosphor is achieved through structural modulation, which exhibits anti‐thermal quenching behavior. Redshift from blue (469 nm) to cyan (500 nm) emission and enhancement of emission is achieved by codoping Mg2+ and Ge4+ into Eu2+‐activated Na‐beta‐alumina phosphor. The introduction of Mg2+ ions dominates the redshift, while Ge4+ dominates the enhancement of emission. Furthermore, the introduction of Mg2+ and Ge4+ reduces the content of deep trap levels related to VNa defect, which decreases the degree of anti‐thermal quenching and results in better thermal stability. The prototype pc‐WLED by using the cyan‐emitting phosphor exhibits higher color‐rendering index and potential to close the cyan gap of pc‐WLEDs for full‐spectrum illumination. This work presents a paradigm for exploring phosphors with highly efficient and thermally stable emissions.

Efficient and tunable emission CsPbClxBr3-x quantum dot glass for overcoming the lack of cyan gap in WLED.

Recently, the photoluminescence (PL) performance and stability of cyan emission perovskite quantum dot (PQD) were found to be inferior to other color emitting PQDs, which greatly limits their practical applications. In this Letter, CsPbClxBr3-x PQD glass with excellent hydrothermal stability is successfully synthesized by a high-temperature melting method. Results review that the vacancy defects in [PbBr6]4- octahedra can be effectively compensated by excessive halogen doping, resulting in an improvement in the photoluminescence quantum yield (PLQY) of PQDs from 24.73% to 65.62%. In addition, compared to white light emitting diode (WLED) synthesized with commercial fluorescent powders, the introduction of CsPbCl2Br1 PQD glass effectively fills the cyan gap. Moreover, the WLED displays the color-rendering index (CRI) of 87 at correlated color temperature (CCT) of 5257 K, and the color gamut area reaches 126% of the National Television System Committee (NTSC). This work provides an effective way for improving the PL performance of PQDs and brings CsPbClxBr3-x PQD glass significant prospect in the optoelectronic applications.

Facile synthesis of multicolor emitting sulfur quantum dots and their applications in light blocking field, anti-counterfeiting and sensing

Sulfur quantum dots (SQDs) have aroused widespread interest from researchers in a wide range of fields due to their excellent photoluminescent properties. Ethylenediamine, diaminopropane and butanediamine were used as precursor amine raw materials to interact with sublimated sulfur to synthesize SQDs with blue, cyan and green fluorescence emission, respectively. Multicolour emitting SQDs were first prepared via sulfur-amine interactions. Further characterization and calculations showed that the precursor amine substances could alter growth size and band gap energy of SQDs to allow for a wider absorption and fluorescence transfer to long wavelength emission region, resulting in tunable fluorescence emission. In terms of application, the excellent down-conversion properties of SQDs were utilized to obtain highly transparent and flexible photoblocking films by blending SQDs with polyvinyl alcohol matrixes, achieving a blocking of light in UV region of up to 99.69 %. In addition, we constructed an encoded storage microarray based on standard 8-bit ASCII character binary codes using BSQDs and GSQDs to store and encrypt important information. Finally, GSQDs-based fluorescent sensors were designed to achieve fluorescent trace detection of o-nitrophenols with limits of detection as low as 2.54 μM. The multicolor emitting SQDs prepared in this work have great potential for applications in analytical detection, optical anti-counterfeiting and light blocking.

Nanomolar detection of hypochlorite in ground water samples by a norbornene-based polymeric sensor via unusual fluorescence turn-on response

Hypochlorite anion has been widely used as a bleaching and disinfecting agent in daily life. Selective and sensitive identification ofOCl-ions from water is very important for researchers. For this purpose, monomeric (NPh), and polymeric (PNPh-Peg) novel fluorescent sensors have been established for the specific and excellently unique sensors that exhibit selective characteristics like excellent resistance to bleaching and a high fluorescence brightness. A multi-functional random polymer (PNPh-Peg) with ICT (intramolecular charge transfer) active para–amino phenol functionality and reactive oxygen species (ROS) responsive, PEG attached are readily prepared via ROMP (ring-opening metathesis polymerization).: An ICT-active random polymer (PNPh-Peg) exhibited an unexpectedly strong cyan blue emission in a water medium compared to that in other common organic solvents, which was dramatically increased by adding a trace amount of NaOCl.: Incorporating PEG moiety in the polymeric backbone increases the water solubility of a copolymer, and the ROS-responsive groups make the polymer a good ROS scavenger. Upon oxidation of the phenol group into carbonyl, both the monomeric (NPh) and polymeric (Norp-PEG oh) sensors showed a selective, noticeable, unusual fluorescence turn-on response towardsanalyteOCl-ions with a very fast response (within three minutes). The detection limit (59.14 nM) and (126.93 nM) were calculated for monomeric and polymeric sensors, respectively. This was a selective, specific oxidation reaction of the completely water-soluble random polymeric sensor (PNPh-Peg) for hypochlorite anions and can be applicable for quantitative measurement of aqueous OCl-. This ICT-active random polymeric molecule (PNPh-Peg) can also be used as a fluorescent sensor for unique OCl- detection from contaminated water by preparing a sensor-coated paper strip. Thus, these multi-functional monomeric (NPh) and polymeric (PNPh-Peg) sensors are anticipated to apply to the environment.

Cyan luminescence from Bi ions-doped borosilicate glass induced by the gradual substitution of MO (M=Ca, Sr, Ba)

At present, amorphous glasses that can give blue light, green light, and yellow light emission upon ultraviolet excitation have achieved good commercial prospect, but lacking of the high-efficiency cyan luminescence is still a challenging problem. To fill the lack of cyan light emission in the current white light LED technology spectrum excited by ultraviolet light, the effect of the substitution of CaO for SrO and BaO, and that of SrO for BaO on the optical properties, structure, DSC, and CIE (Commission International de L'Eclairage) coordinates of Bi ions-doped borosilicate glasses were systematically studied in this work. The emission spectra results reveal that the emission position of Bi ions-doped borosilicated glasses is observed from 482 nm to 492 nm when CaO is gradually replaced by SrO, from 482 nm to 502 nm when CaO is gradually replaced by BaO. In one word, the luminescent peak position of the Bi ions-doped borosilicate glass can be easily tuned by altering the concentration of basicity-earth oxide modifier, and the cyan light emission can be finally achieved.

AIEE activated Pyrene-Dansyl coupled FRET probe for discriminating detection of lethal Cu2+ and CN–: Bio-Imaging, DNA binding studies and prompt prognosis of Menke’s disease

In present work a pyrene-dansyl dyad functionalized chemoreceptor, DPNS is unveiled towards ultrasensitive chromo-fluorogenic detection of heavy and transition metal ions (HTMs) like Cu2+ and pernicious CN–. It demonstrated distinct chromogenic responses; colorless to faint yellow (Cu2+), intense yellow (CN–) from contaminant aqueous sources. Cu2+ instigated alteration in DPNS fluorescence from feeble emission to sparkling green with LOD: 37.75 × 10-9 M, cyan emission for CN– having LOD 61.51 × 10-8M. In particular, chemical scaffold of DPNS consists of –C = N, O = S = O donor entitities that escalates overall polarity thereby providing an excellent binding pocket for simultaneous Cu2+ and CN– recognition with distinct photophysical signaling. Impressively, presence of two fluorophoric moieties triggers FRET, CHEF phenomenon. The conceivable host:guest interactive pathway is manifested by LMCT- FRET-PET-CHEF, C = N isomerization for Cu2+ and ICT-H-bonding for CN–. An exquisite experimental and theoretical corroboration further strengthened the recognition phenomenon. In addition owing to pyrene excimer formation, DPNS exhibits AIEE with increasing water fraction. Notably, DPNS could successfully undergo intracellular tracking of Cu2+ in Tecoma Stans, Peperomia Pellucida. DPNS•••Cu2+ adduct displayed significant intercalative DNA binding activity rationalized by spectral investigation, competitive EB binding, viscosity study. The overall findings, excellent properties endows DPNS a potential contender towards discriminative detection of Cu2+ and CN– like toxic industrial contaminants.

Efficient blue-light-excited cyan-emitting CaLu2HfScAl3O12:Ce3+ phosphors for full-visible-spectrum warm-white LEDs

Bright cyan-emitting phosphor is indispensable to fill the cyan gap for the fabrication of full-visible-spectrum warm-white light-emitting diodes (LEDs) with high color rendering index (CRI). In this study, we demonstrate a novel efficient cyan-emitting Ce3+-activated CaLu2HfScAl3O12 (CLHSA) garnet phosphor for application in blue-light-excited full-spectrum warm-white LEDs. CLHSA:Ce3+ phosphors show broadband excitation spectra in the 300–470 nm spectral range with a maximum peak at 408 nm, indicating they can be efficiently pumped by the blue LED chips. The optimal doping concentration of Ce3+ ions is found to be 1 mol%. Upon 408 nm excitation, the optimal CLHSA:1%Ce3+ phosphor gives rise to a bright broadband cyan emission (peak position: 498 nm; bandwidth: 97.5 nm) with CIE chromaticity coordinates of (0.2196, 0.4265) and high photoluminescence quantum yield of 64.5%. Finally, we have fabricated a blue-light-excited high-CRI warm-white LED device by employing the CLHSA:1%Ce3+ cyan phosphor, commercial YAG:Ce3+ yellow phosphor and commercial CaAlSiN3:Eu2+ red phosphor as well as a 450 nm LED chip, which demonstrates a bright warm-white light emission with a high CRI (Ra = 92.6), a low correlated color temperature (3660 K), and good CIE chromaticity coordinates of (0.3993, 0.3939) as well as a high luminous efficacy of 45 lmW−1. Therefore, this newly discovered efficient cyan-emitting CLHSA:1%Ce3+ phosphor is promising for application in blue-chip-pumped full-visible-spectrum warm-white LEDs with high CRI values.

Highly bright broadband cyan-emitting CaLu2HfGaAl3O12:Ce3+ garnet phosphors for high-color-quality white light-emitting diodes

In this work, novel highly efficient cyan-emitting Ce3+-activated CaLu2HfGaAl3O12 (abbreviated as CLHGAO) garnet-structured phosphors were synthesized using the high-temperature solid-state reaction route. Rietveld refinement results demonstrate the as-prepared samples belong to cubic space group Ia3‾d. These CLHGAO:xCe3+ (x = 0.5–8%) phosphors possessed a broad absorption band in the 320–450 nm wavelength range with a maximum at 408 nm. Upon 408 nm excitation, the CLHGAO:0.5%Ce3+ sample showed a broad cyan emission band within 425–750 nm wavelength range (emission peak: 493 nm; bandwidth: 95 nm), along with CIE color coordinates of (0.1939, 0.3533) and a high internal quantum efficiency of 81.9%. It is observed that, with increasing Ce3+ doping concentration from 0.5% to 8%, the emission peak position of CLHGAO:xCe3+ moves from 493 nm to 527 nm, and the corresponding emission color changes from cyan to green. Besides, the thermal stability and color stability of CLHGAO:0.5%Ce3+ phosphor at high temperature are also studied. A white LED device was fabricated by utilizing a 395 nm LED chip with as-prepared CLHGAO:0.5%Ce3+ cyan-emitting phosphor and commercial (Ba,Sr)2SiO4:Eu2+ green-emitting phosphor and commercial CaAlSiN3:Eu2+ red-emitting phosphor, and it demonstrates a high-color-quality white light with high color rendering index of 91, low color correlated temperature of 3547 K and good luminous efficacy of 58.71 lmW−1.

From Framework to Layers Driven by Pressure - The Monophyllo-Oxonitridophosphate β-MgSrP3 N5 O2 and Comparison to its α-Polymorph.

Oxonitridophosphates exhibit the potential for broad structural diversity, making them promising host-compounds in phosphor-converted light-emitting diode applications. The novel monophyllo-oxonitridophosphate β-MgSrP3 N5 O2 was obtained by using the high-pressure multianvil technique. The crystal structure was solved and refined based on single-crystal X-ray diffraction data and confirmed by powder X-ray diffraction. β-MgSrP3 N5 O2 crystallizes in the orthorhombic space group Cmme (no. 67, a=8.8109(6), b=12.8096(6), c=4.9065(3) Å, Z=4) and has a structure related to that of Ba2 CuSi2 O7 . DFT calculations were performed to investigate the phase transition from α- to β-MgSrP3 N5 O2 and to confirm the latter as the corresponding high-pressure polymorph. Furthermore, the luminescence properties of Eu2+ doped samples of both polymorphs were investigated and discussed, showing blue and cyan emission, respectively (α-MgSrP3 N5 O2 ; λmax =438 nm, fwhm=46 nm/2396 cm-1 ; β-MgSrP3 N5 O2 ; λmax =502 nm, fwhm=42 nm/1670 cm-1 ).

Photoluminescent pyrene-based ionic liquid derived ratiometric organo nanosensor for rapid and selective detection of picric acid

Due to the rising menace of illicit actions and pollution aroused by explosive nitroaromatic compounds (NACs), the growth of an adept sensor for detecting these NACs is highly essential. Herein, in this communication, a photoluminescent IL-assimilated group of uniform materials based on organic salt (GUMBOS) and nano-GUMBOS has been fabricated by integrating pyrene butyrate with a quaternary phosphonium IL (PbIL) via a simple ion exchange process. Neat PbIL shows a bright cyan color photoluminescence under a 365 nm UV lamp irradiation and is employed as photoluminescence security ink and picric acid (PA) detection among the tested NACs. By simple reprecipitation method, we have developed water-suspended crystalline pyrene assimilated nanoparticles, nPbIL, characterized by various analytical techniques. The PbIL-derived water-suspended nanomaterials, nPbIL, display a robust cyan color excimer-like emission, which turns blue (monomeric) due to adding PA over the other related NACs. This ratiometric cyan to blue photoluminesce change is due to the displacement of the anionic pyrene moiety of the nPbIL by the picrate anion. The fabricated organo nanosensor is enormously discerning and responsive towards PA with a detection limit of 0.77 nM and is found to be superior to many available in the literature. Additionally, a fluorogenic paper strip-based test kit experiment has been demonstrated to detect and quantify PA selectively in aqueous solvents amongst the other tested NACs. The present contribution evokes a novel approach to developing different IL-based chemosensors for detecting and quantifying various target analytes.

Synthesis by microwave irradiation of new pyrazole-imidazoline-pyrimidine analogs: Physicochemical and photophysical properties and their biological activity against Trypanosoma cruzi

Pyrazole derivatives are pharmacologically important agents that possess a wide spectrum of biological activities. Thus, the optimization of their synthetic approaches is of great interest for medicinal and pharmaceutical chemistry. In this work, eleven new 7-aryl-2,3-dihydro-7H-imidazo[1,2-c]pyrazolo[4,3-e]pyrimidines 1(a-k) were synthesized employing microwave irradiation conditions (150 W, 15–45 min). All compounds were completely characterized through Fourier Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR), and High-resolution Mass Spectrometry (HRMS) analyses. The in silico prediction of physicochemical properties showed that all analogs do not violate Lipinki's rule with prediction of good oral bioavailability. Analogs showed low activity against T. cruzi. Correlated experimental methods have been applied to investigate the photophysical properties of 1(a-k), describing their absorption properties in function of substituents. The molecular set exhibits a cyan emission, enabling it to investigate the basic fluorescence spectroscopy in solution.

Efficient, stable, broadband cyan‐emitting Ca‐substituted Ba9Lu2Si6O24:Eu2+ with multisite luminescence for NUV‐wLEDs

AbstractIn order to develop an efficient and stable broadband cyan phosphor for full spectrum white lighting emitting diodes (wLEDs), novel Ba9Lu2Si6O24:Eu2+, xCa2+ is designed and synthesized. Ca‐substitution induces Eu2+ ions into Lu3+ crystallographic site, which achieve rare nonequivalent cation substitution of Eu2+. Effects of Ca‐substitution on crystal structure of matrix and phosphor are investigated by X‐ray photoelectron spectroscopy, X‐ray powder diffraction, transmission electron microscopy, and density functional thoery (DFT). Ba9Lu2Si6O24:Eu2+, xCa2+ can be effectively excited by with near‐ultraviolet (NUV) and exhibit broadband cyan emission with full width at half maximum (FWHM) of 119.7 nm at x = 0.2, due to the multisite luminescence centers. For the sample x = 0.2, the internal quantum efficiency is 92.61%, and the luminous intensity at 423 K remains 89% of that measured at room temperature. The rigid structure of [SiO4]‐[LuO6]‐[SiO4] doped with Eu2+ ion makes Ca‐substituted samples exhibit excellent luminescence efficiency and thermal stability. Our work develops a significant strategy based on multisite cation regulation to explore NUV‐excited broadband cyan phosphors for full spectrum wLEDs.

Red, orange, and dual wavelength vortex emission from Pr:WPFGF fiber laser using a microscope slide output coupler.

Visible vortex beams have a large array of applications; however, the sources are often large or complex. Here, we present a compact vortex source with red, orange, and dual wavelength emission. This Pr:Waterproof Fluoro-Aluminate Glass fiber laser uses a standard microscope slide as an interferometric output coupler, yielding high quality first order vortex modes in a compact setup. We further demonstrate the broad (∼5 nm) emission bands in the orange (610 nm), red (637 nm) and near-infrared regions (698 nm), with the potential for green (530 nm) and cyan (485 nm) emission. This is a low-cost, compact and accessible device giving high quality modes for visible vortex applications.

A nitriding garnet structure cyan emitting phosphor Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 with high efficiency and excellent thermal stability

Cyan phosphors with high efficiency and excellent thermal stability are an important part for application in full spectrum illumination. Herein, a series of nitriding cyan emission phosphors Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 with garnet structure are successfully synthesized, their phase purity, crystal structure, morphology, elemental composition and valence state are analyzed in detail, and the results indicate that a small amount of Si3N4 doping does not cause impurity phase. The phosphor has an efficient broadband cyan emission at 493 nm with full width at half maximum (FWHM) of about 95 nm under 411 nm excitation. Impressively, the luminous intensity of the nitriding phosphor is increased by 30%, the internal/external quantum efficiency are increased from 41.63% and 40.01% to 61.93% and 52.13%, and the thermal stability is improved from 75%@150 oC to 85%@150 oC, which is even better than the commercial green phosphor LMS520B (77%@150 oC). Finally, a full-visible-spectrum LED with low correlated color temperature (CCT = 5143 K) and high color rendering index (Ra = 98.3) is fabricated by employing Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 phosphors as cyan emitting component. The results indicate that the nitriding Ca2(Y, Ce)Hf2(Al, Si)3(O, N)12 phosphors have potential to act as cyan emission phosphors for full-visible-spectrum LEDs.

Nanocrystalline CdS thin films deposited by sol-gel spin coating method: Effect of aging and doping on structural, optical, and electrical properties

This work deals with the synthesization of pristine and Fe-doped CdS nanocrystalline thin films by the sol-gel spin coating method with the freshly prepared solution (Set-A) and 24 h aged solution (Set-B). The XRD patterns of pristine and Fe-doped nanocrystalline CdS thin films (Set-A) reveal hexagonal structure and the other films of set-B exhibit cubic structure. The average crystallite size of all pristine and Fe-doped nanocrystalline CdS thin films (Set-A and Set-B) was found to be lying in the range of 4.997–17.142 nm. The particle size calculated from TEM studies was found to be 11.14 nm, 10.74 nm and 8.74 nm for pristine, 2 ml Fe doped, and 5 ml Fe doped CdS thin films. The average surface roughness of the films was found to be 0.1518 nm, 4.2216 nm, and 0.1471 nm for Fe_00, Fe_01, and Fe_05 samples of Set-A, while it was found to be 0.2055 nm, 4.839 nm and 0.1803 nm for Fe_00, Fe_01 and Fe_05 samples of Set-B respectively. PL spectra reveal the occurrence of cyan emission for both sets of samples. The band gap values for the nanocrystalline thin films (Set-A) were 2.46–2.71 eV and for Set-B were in the range of 2.47–2.75 eV, which is higher than that of bulk CdS (2.42 eV). The low-temperature resistivity of the deposited films of both sets was obtained in the range of 105 to 103 Ω cm, and also found to decrease with increasing Fe concentration in CdS.

GSH and H2O2 dynamic correlation in the ferroptosis pathways revealed by engineered probe in tumor and kidney injury

Ferroptosis is a cell death mode of lipid peroxidation caused by iron metabolism disorder and redox imbalance, which is closely associated with the evolution of tumour and ischemia reperfusion injury and other diseases, and it involves the excessive accumulation of reactive oxygen species promoting ferroptosis pathway and thiols-associated anti-ferroptosis pathway. To study the dynamic correlation between reactive oxygen species and active sulfur in the two pathways is of great significance for revealing the precise regulation mechanism of ferroptosis. Hydrogen peroxide (H2O2) and glutathione (GSH), as very active redox species in organisms, participate dynamically in the ferroptosis process. In this study, hemicyanine dye conjugated H2O2 specific response site were coupled with coumarin derivative containing GSH specific response site, realizing distinguishing simultaneous detection of H2O2 and GSH through near-infrared and cyan fluorescence emission after response. At the cellular level, the dynamic correlation between H2O2 and GSH in the ferroptosis pathway was explored, and the synergistic ferroptosis inducer was screened for further application at the tumor level, then monitoring the process of ferroptosis inducer used for tumor ablation and ferroptosis inhibitor used to alleviate kidney ischemia–reperfusion injury by fluorescence imaging.

Tunable Efficient White Emission in Holmium Doped Double Perovskites Cs2KInCl6 via Antimony Sensitization

AbstractRecently, ns2 metal ions (such as Bi3+ and Sb3+) doped double perovskites have captured intense attention for their efficient emission, however, achieving efficient and tunable white light emission is always an enormous challenge. Herein, Sb3+/Ho3+ co‐doped Cs2KInCl6 double perovskites are proposed, and the photoluminescence results show that there are two emission bands, one broad cyan emission band stems from self‐trapped exciton (STE) in [SbCl6]3‐ octahedron, while another red emission band derives from the f‐f transitions of Ho3+. The emission processes for Sb3+/Ho3+ co‐doped Cs2KInCl6 show that Sb3+ can act as the sensitizer to activate Ho3+ emission, which is due to the energy transfer channel from STE to Ho3+. As the Ho3+ concentration increases, the luminous color of Sb3+/Ho3+ co‐doped Cs2KInCl6 can be modulated from cyan to orange under 315 nm light irradiation, and the white emission can even be obtained with a photoluminescence quantum yield of 90 ± 2% when the energy‐transfer efficiency is 50%. Finally, single compound white‐light emitting diodes and fluorescent anti‐counterfeiting labels based on 0.5%Sb3+/60%Ho3+ co‐doped Cs2KInCl6 are fabricated. This work provides an effective strategy to achieve efficient tunable white emission in lead‐free double perovskites through ns2 metal and lanthanide ion co‐doping.

Crystal packing and photoelectric property of bis(2-picolyl)amine-functionalized triarylborane and its complexes

Organic crystalline materials are attracting increasing interest due to their promising applications in the fields of nonlinear optics (NLO), organic lasers, optical waveguides, and light-emitting transistors. In this paper, a photoelectric molecule QB was constructed through combining an electron-withdrawing unit, a triarylborane, and a metal-ligand unit of bis(2-picolyl)amine. The crystallization behavior and crystalline photoelectric properties of QB and its complexes were thoroughly studied. This compound exhibited polymorphism, and a green emitting block-like crystal and blue-emission lamellar crystal were obtained, respectively. Their different photoluminescence mechanisms were clarified through X-ray crystallographic analysis and theoretical calculations. Furthermore, the single-crystal structures of the complexes of QB coordinating with KCN and Zn(ClO4)2 were also determined. Crystal QB-KCN emitted strong blue fluorescence at 445 nm, owing to the formation of rigid 2-to-2 adduct, which could effectively suppress non-radiative transitions. Crystal QB-Zn(ClO4)2 showed very weak cyan emission due to its loose molecular packing. The electrochemical results illuminated that the metal coordination can effectively affect the electron-withdrawing ability of conjugated triarylborane, and further affect the monomolecular luminescent properties due to the intramolecular charge transfer. We believe that polymorphism and metal coordination are available means to obtain excellent crystalline photoelectric materials.