Tunable Full-color Emission Research Articles

Tunable full-color emission phosphors: Enhanced security application via a patterned 3-dimensions code

Developing tunable full-color emission photoluminescent materials is always desired in color-on-demand applications and still confronts challenges. Theoretically, full color including white emission can be achieved by the combination of three primary colors (red, green, and blue) based on the additive color theory. Herein, a strategy for the preparation of tunable full-color luminescence is realized by mixing the inorganic rare-earth-doped SrAl 2 O 4 : Eu 2+ , Dy 3+ (green emission), Y 2 O 2 S: Eu 3+ , Mg 2+ , Ti 4+ , Ti 4+ 0.05 (red emission), and Sr 2 MgSi 2 O 7 : Eu 2+ , Dy 3+ (blue emission) phosphors with different ratios. By adjusting individual phosphors at certain specific ratios, white light (0.332, 0.332) and full-spectra emission are achieved under a single low excitation energy (λ ex = 365 nm) using a portable ultraviolet (UV) lamp. Based on the facile preparation and effective tunable full-color emission features of the phosphors, a novel encryption way of the luminescent unit as information storage 3 dimensions (3D) codes is developed. The multiplexed encrypting information capacity of the codes is enhanced in a 3D maneuver strategy by simply adjusting the number of light-emitting units with infinite emission colors. The proposed strategy makes the tunable full-color emission phosphors useful in promising applications including full-color display, high-level information encryption and anti-fake.

Independent dual-responsive luminous composite fibers with controllable full-color emissions

Accumulated ultraviolet (UV) under high temperature is prone to cause photoaging, skin burns, and even induce skin cancers during outdoor activities. Fiber-based wearable sensors with color-tunable luminescent ability are urgently demanded for real-time monitoring of human health conditions to enhance personal awareness of these hazards. To achieve tunable full-color emission, a set of three primary colors (red, green, and blue) of rare-earth doped persistent luminescent phosphors are successfully synthesized. After simply mixing them with particular ratios, a tunable full-color emission system can be realized. Herein, by integrating the thermochromic dyes, photochromic dyes, and luminescent phosphors directly into polyacrylonitrile (PAN) matrix, novel thermo-UV-sensing composite fibers with color-tunable luminescent ability are prepared via the facile wet-spinning process. The obtained fibers can be switched among four different colors with brilliant reversible color changes in response to temperature and UV irradiation both independently and in combination. Besides, the fibers can emit tunable emissions under in full spectral range 365 nm excitation. This work paves the way for as-prepared fibers for diverse applications including energy-free, wearable real-time monitors of the temperature/UV, and high-level information encryption.

Photoluminescence properties of tunable full-color-emitting CaZrO3: Ln (Ln = Tb3+, Eu3+, Tb3+/Eu3+) phosphors for white LEDs

A series of single-phase color-turning CaZrO3: Ln (Ln = Tb3+, Eu3+, Tb3+/Eu3+) phosphors was synthesized through citric acid-fueled combustion method. The as-prepared samples had the perovskite structure with Pnma space group and elements uniformly distributed in nanosized particles. CaZrO3: Eu3+ phosphor produced red luminescence due to the 5D0→7F2 transition at 619 nm CaZrO3: Tb3+ phosphor produced green and blue luminescence due to the 5D4→7F6, 5 transition at 487 nm and 548 nm. Under UV irradiation at 254 nm, the CaZrO3: Ln (Ln = Tb3+, Eu3+, Tb3+/Eu3+) phosphors achieved tunable full-color emission in a wide range from blue to green, warm white, and red. The corresponding CIE coordinates were (0.2546, 0.2413), (0.3196, 0.5085), (0.3603, 0.3896) and (0.6089, 0.3844). The energy transfer from ZrO32− to Tb3+ and then to Eu3+ was determined by the dipole-dipole mechanism in CaZrO3: 0.03 Tb3+, xEu3+ phosphors. The excellent temperature stability of CaZrO3: 0.03 Tb3+, 0.01Eu3+ phosphor (ΔE = 0.2659 eV) indicates that CaZrO3: Ln (Ln = Tb3+, Eu3+, Tb3+/Eu3+) phosphors have broad application prospects in W-LED devices.

A Continuously Tunable Full-Color Emission Nitrogen-Doped Carbon Dots and for Ultrasensitive and Highly Selective Detection of Ascorbic Acid.

Nitrogen-doped carbon dots exhibiting excitation-dependent full-color emissions (F-NCDs) were prepared via the one-step hydrothermal method with citric acid and phenylenediamine. Specifically, the emission wavelength of the F-NCDs tuned from 452 nm to 602 nm due to the introduction of new energy levels by C=O and C=N functional groups. We exploited its stability in illumination, ionic strength, and pH, as well as its specificity, sensitivity, especially in ascorbic acid (AA) detection. F-NCDs could measure the AA concentration in the linear ranges of 0~0.1 and 0.1~1 mmol/L with the detection limit (LOD, S/N = 3) as low as 2.6 nmol/L. Additionally, we successfully detected AA in bovine serum with our F-NCDs and obtained the result within 1 min. Because of full-color emission features, we believe our F-NCDs have a great potential in fluorescent sensor detection.

Conditional controlled nano coordination polymers with tunable full color light emitting

Nanosized coordination polymers (NCPs) and their thin films with tunable full-color fluorescence emission, simple preparation, and good biocompatibility are highly desirable for optical and biomedical applications. Changes in the reaction conditions for fluorescent NCP@PEI and its thin films with tunable full-color emission are the first to be presented as the result of surface modification of PEI-induced band gap changes. Significantly, a white emitting fluorescence-calculated CIE value of (0.308, 0.312) can be observed by mixing NCP@PEI, and NCP@PEI-based poly (vinyl alcohol) (PVA) films with tunable full-color emission were obtained. The reaction condition effect is of particular importance for optical applications, where it can provide a new route to design NCP- or metal organic framework-based materials.

Oxygen/nitrogen-related surface states controlled carbon nanodots with tunable full-color luminescence: Mechanism and bio-imaging

Fluorescent carbon nanodots (CNDs) have exhibited attractive potential for biomedical applications due to their intriguing luminescent properties and good biocompatibility. One interesting property of CNDs is that they typically show different emission colors upon optical excitation using different wavelengths. However, it is still a challenge to obtain emissions covering the entire visible spectrum with comparable intensity with only one type of CND. Herein, CNDs with tunable full-color luminescence are successful prepared by a solvothermal approach, show broad absorption (200–700 nm) and fluorescence emission (nearly cover the entire visible region: from 400 to 700 nm) with comparable fluorescence intensities. The oxidation (o-CNDs) and reduction (r-CNDs) of CNDs surface would lead to the shifting of photoluminescence band into blue/green and red-light region, respectively. Further spectroscopic analyses and structural characterizations of CNDs (pristine state), o-CNDs (oxidation state) and r-CNDs (reduction state) demonstrate that O-related defect states (CO) and N-related defect states (CN) on surface of CNDs should be responsible for blue/green and red fluorescence emissions, respectively. Moreover, the CNDs are found to be biocompatible, as verified by in vitro cells assay and in vivo histological analysis. In vivo fluorescence imaging assay demonstrates that CNDs can be excreted through intestine and bladder system. The tunable full-color emission, good biocompatibility and metabolism suggest that the CNDs are promising fluorescent probes for biomedical applications.

Carbon nanodots with intense emission from green to red and their multifunctional applications

In this report, carbon nanodots (CDs) with tunable full-color emission were successfully synthesized by a solvothermal method. By changing the carbon source (p-phenylenediamine or o-phenylenediamine) and the concentration, green, yellow, orange and red CDs (GCDs, YCDs, OCDs and RCDs) were successfully fabricated. As the concentration of the starting materials was increased, the emission peak was red-shifted. The shifted peaks showed strong intensity and an obvious color change. This concentration-dependent effect was attributed to the reabsorption phenomenon. Carbon source was critical in determining the fluorescence properties and the quantum yield (QY) of full-color CDs was high. The CDs also presented a distinct pH sensitivity. The PL intensity of RCDs showed linear decreases over decreasing pH from 11 to 4 and from 4 to 2. Fluorescent oil carrying CDs was successfully applied for various purposes such as anti-counterfeiting, information encryption and storage purposes. An RCD film was successfully fabricated that could improve the correlated color temperature and color rendering index of white light-emitting diodes.

Hybridizing Carbon Nitride Colloids with a Shell of Water-Soluble Conjugated Polymers for Tunable Full-Color Emission and Synergistic Cell Imaging.

We present the preparation of a new multicolor emission system constructed from two complementary conjugated materials that are highly photoluminescent, that is, phenyl-modified carbon nitride (PhCN) colloids as the core and water-soluble conjugated polymers (WSCPs) adsorbed as the shell. The fluorescence bands of the PhCN and WSCPs effectively complement each other and the overall emission can be simply adjusted to fully cover the visible light spectrum with white light emission also accessible. Photophysical insights imply that the interactions between PhCN and WSCPs preserve the binary system from emission distortion and degradation, which is essential to delicately tune the overall fluorescence bands. Notably, the continuously tunable emission color is achieved under single-wavelength excitation (365 nm). This hybrid shows a synergistic permeation performance in cell imaging, that is, PhCN nanoparticles help the WSCP to enter the cells and therefore multicolor cellular imaging achieved.

Air-Stable Spirofluorene-Containing Ladder-Type Bis(alkynyl)borane Compounds with Readily Tunable Full Color Emission Properties.

A series of air-stable spiro-fused ladder-type boron(III) compounds has been designed, synthesized, and the electrochemistry and photophysical behavior have been characterized. By simply varying the substituents on the pyridine ring and extending the π-conjugation of the spiro framework, the emission color of these compounds can be easily fine-tuned spanning the visible spectrum from blue to red. All compounds exhibit a broad and structureless emission band across the entire visible region, assigned as an intramolecular charge-transfer transition originating from the thiophene of the spiro framework to the pyridine-borane moieties. In addition, these compounds demonstrate high photoluminescence quantum yields of up to 0.81 in dichloromethane solution and 0.86 in doped thin films. Some of the compounds have also been employed as emissive materials, in which solution-processed organic light-emitting devices (OLEDs) with tunable emission colors spanning the visible spectrum from blue, green to red have been realized, demonstrating the potential applications of these boron compounds in OLEDs.

A single-phase Ba9Lu2Si6O24:Eu2+, Ce3+, Mn2+ phosphor with tunable full-color emission for NUV-based white LED applications

We obtained a single phase BLS:Eu2+, Ce3+, Mn2+ phosphor by solid-state reactions. Eu2+, Ce3+, and Mn2+ gives rise to the blue, green, and red emission, respectively. The Mn2+ red emission can be effectively enhanced via energy transfers from both Eu2+ and Ce3+. Thus a tunable full color emission from 410 to 750nm was realized in this single phosphor. The Eu2+→Mn2+ energy transfer mechanism was investigated by the fluorescence decay curves. This single phosphor exhibits an efficient excitation band covering from 390 to 410nm, which matches well with the emission light of the efficient NUV chips. The optimized BLS:Eu2+, Ce3+, Mn2+ phosphor shows a high quantum efficient of ∼62% and a good color stability. When this single phosphor was combined with a 395nm NUV-chip, an ideal white LED with a high color render index (CRI) of 85 and a correlated color temperature (CCT) of 6300K was obtained. This demonstrates the promising application of the BLS:Eu2+, Ce3+, Mn2+ single phosphor for the NUV-based white LEDs.

Self-Targeting Fluorescent Carbon Dots for Diagnosis of Brain Cancer Cells.

A new type of carbon dots (CD-Asp) with targeting function toward brain cancer glioma was synthesized via a straightforward pyrolysis route by using D-glucose and L-aspartic acid as starting materials. The as-prepared CD-Asp exhibits not only excellent biocompatibility and tunable full-color emission, but also significant capability of targeting C6 glioma cells without the aid of any extra targeting molecules. In vivo fluorescence images showed high-contrast biodistribution of CD-Asp 15 min after tail vein injection. A much stronger fluorescent signal was detected in the glioma site than that in normal brain, indicating their ability to freely penetrate the blood-brain barrier and precisely targeting glioma tissue. However, its counterparts, the CDs synthesized from D-glucose (CD-G), L-asparic acid (CD-A), or D-glucose and L-glutamic acid (CD-Glu) have no or low selectivity for glioma. Therefore, CD-Asp could act as a fluorescence imaging and targeting agent for noninvasive glioma diagnosis. This work highlights the potential application of CDs for constructing an intelligent nanomedicine with integration of diagnostic, targeting, and therapeutic functions.

Reply to Comment on “Carbon Dots with Continuously Tunable Full-Color Emission and Their Application in Ratiometric pH Sensing”

ADVERTISEMENT RETURN TO ISSUEPREVCommentsNEXTReply to Comment on “Carbon Dots with Continuously Tunable Full-Color Emission and Their Application in Ratiometric pH Sensing”Minjie Li* and Sean Xiao-An Zhang*View Author Information State Key Lab of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Avenue, Changchun, 130012, China*(M.L.) E-mail: [email protected]*(S.X.-A.Z.) E-mail: [email protected]Cite this: Chem. Mater. 2014, 26, 20, 6084Publication Date (Web):October 1, 2014Publication History Received4 September 2014Revised5 September 2014Published online8 October 2014Published inissue 28 October 2014https://doi.org/10.1021/cm503256mCopyright © 2014 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1017Altmetric-Citations3LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (145 KB) Get e-AlertsSUBJECTS:Carbon,Ethanol,Evaporation,Lipids,Mixtures Get e-Alerts

Comment on “Carbon Dots with Continuously Tunable Full-Color Emission and Their Application in Ratiometric pH Sensing”

ADVERTISEMENT RETURN TO ISSUEPREVCommentsNEXTComment on “Carbon Dots with Continuously Tunable Full-Color Emission and Their Application in Ratiometric pH Sensing”Edwin A. ChandrossView Author Information MaterialsChemistry LLC, Murray Hill, New Jersey 07974, United StatesCite this: Chem. Mater. 2014, 26, 20, 6083Publication Date (Web):September 2, 2014Publication History Received30 July 2014Published online8 October 2014Published inissue 28 October 2014https://doi.org/10.1021/cm5028157Copyright © 2014 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1314Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (144 KB) Get e-AlertsSUBJECTS:Fluorescence,Mixtures,Nanodots,Oxygen,Solutions Get e-Alerts

Increased Eu²⁺ content and codoping Mn²⁺ induced tunable full-color emitting phosphor Ba(1.55)Ca(0.45)SiO₄:Eu²⁺,Mn²⁺.

We demonstrated that a new intermediate composition of Ba(1.55)Ca(0.45)SiO4 between the orthosilicates Ca2SiO4 and Ba2SiO4 yields the best phosphor hosts, and interesting luminescence properties can be found from the Eu(2+) singly doped and/or Eu(2+)/Mn(2+) codoped Ba(1.55)Ca(0.45)SiO4 phosphors. The phosphors can be excited by near-ultraviolet (nUV) light at wavelengths ranging from 200 to 450 nm matching well with the nUV light-emitting diode (LED) chips. As a result of fine-tuning the activators of different Eu(2+) content and Eu(2+)/Mn(2+) couples with different ratios, tunable full-color emission under UV light excitation can be realized by combining the blue emission (460 nm) and green emission (520 nm) originating from Eu(2+) with the red emission (595 nm) from Mn(2+) in the Ba(1.55)Ca(0.45)SiO4 host lattice. Energy-transfer efficiency between Eu(2+) and Mn(2+) increases and tunable emission can be obtained with increasing Mn(2+) doping content. These results indicate that the Ba(1.55)Ca(0.45)SiO4:Eu(2+),Mn(2+) phosphor will have potential use in nUV chip pumped white LED devices.

Carbon Dots with Continuously Tunable Full-Color Emission and Their Application in Ratiometric pH Sensing

Two types of carbon dots (C dots) exhibiting respective excitation-independent blue emission and excitation-dependent full-color emissions have been synthesized via a mild one-pot process from chlo...

Red emission of additional Pr³⁺ and adjusting effect of additional Mg²⁺ in Ca₃Sc₂Si₃O₁₂:Ce³⁺, Mn²⁺ phosphor.

In this Letter, we report the addition of Pr3+ and Mg2+ in CSS:Ce3+, Mn2+ phosphor for improving the performances of white light-emitting diodes (LEDs). The additional trivalent Pr3+ will occupy the Ca2+ site in this host like the situation of Ce3+, its concentration can be enhanced by the addition of Mg2+ in Sc3+ site due to the substitution of Mg2+ for Sc3+ can compensate the charge mismatch between Pr3+ and Ca2+. Based on the efficient Ce3+→Pr3+ and Mn2+→Pr3+ energy transfers (ETs) and the compensation effect of Mg2+, the additional Pr3+ in our present phosphors exhibits an intense red-emission around 610 nm, which is significant for enhancing the color rendering property. In addition, we also find that the additional Mg2+ in Sc3+ site can markedly adjust the photoluminescence (PL) spectrum shape of our phosphor by controlling the distribution of Mn2+ at Ca2+ and Sc3+ sites. A new tunable full-color emission is obtained via the ETs (Ce3+→Mn2+, Ce3+→Pr3+ and Mn2+→Pr3+) and the adjusting effect of Mg2+ in our present phosphors. Finally, a white LED with higher color rendering index of 90, lower correlated color temperature of 4980 K, and chromaticity coordinates of (0.34, 0.31) was obtained by combining the single CSS:0.08Ce3+, 0.01Pr3+, 0.3Mn2+, 0.2Mg2+ phosphor with a blue-emitting InGaN LED chip.

All-silicon solid films with highly efficient and tunable full-color photoluminescence

Silicon nanocrystals with the most probable diameter of 2 nm are surface passivated by glycerol and deposited on porous silicon (PS) substrate with intrinsic red photoluminescence. Tunable full-color emission is observed from this composite film and the quantum efficiency varies from 17% to 28% under different excitation wavelengths. Spectral analysis reveals that the full-color emission arises from combined quantum confinement in the silicon and PS nanocrystals with glycerol passivation. The nanostructured all-silicon film is robust and compatible with microelectronic processing.

Tunable full-color emission of two-unit stacked organic light emitting diodes with dual-metal intermediate electrode

The color-tunable stacked organic light-emitting devices (SOLEDs) with independently-addressable intermediate Al/Au electrode are examined. High brightness color-tunable SOLED can be achieved by properly optimizing the Al/Au electrode and using appropriate electron- and hole-injection layer. Full-color emission is achieved in a simple device structure with features of (1) only two-unit SOLED, and (2) the intermediate electrode is the Al/Au dual metal layers which are easy to process and have no damage to the organic layer.