skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Rare-earth single atom based luminescent composite nanomaterials: Tunable full-color single phosphor and applications in WLEDs
Title: Rare-earth single atom based luminescent composite nanomaterials: Tunable full-color single phosphor and applications in WLEDs
High-quality single-component white phosphors are instrumental in realizing high-efficiency devices. Rare earth fluorides and carbon quantum dots have great potential in the white light-emitting diode (WLED) field due to their unique advantages. Here, Rare-earth single atom based NaGdF4:Tb3+/Eu3+@C:N/Eu3+ single phosphor with tunable full-color luminescence was reported. The results of density functional theory (DFT) calculation and experimental characterization show that C atoms cannot be replaced by Eu3+, but C atoms are more favorable for anchoring Eu3+ single atoms. The DFT was employed to optimize the structures of the C:N/Eu3+ and NaGdF4:Tb3+/Eu3+, and calculate the work function, optical properties, and charge density difference. The obtained tunable full-color single phosphor can emit stable light from blue to red or even white. The constructed WLED devices also have stable and excellent color performance, that is, a color rendering index of up to 95 and a lower color temperature, and it has broad application possibilities in WLEDs.  more » « less
Award ID(s):
1945558
PAR ID:
10317153
Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
Nano Research
ISSN:
1998-0124
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, Journal of Materials Chemistry C)
    null (Ed.)
    There is a significant need to identify cyan-emitting phosphors capable of filling the “cyan-gap” (480–520 nm) in full-visible-spectrum phosphor-converted white light-emitting diodes (pc-wLEDs). Here, a new broadband cyan-emitting phosphor that enables addressing of this challenge is reported. The compound, Ba 2 CaB 2 Si 4 O 14 :Ce 3+ , presents a bright cyan emission peaking at 478 nm with a large full width at half maximum of 142 nm (6053 cm −1 ), and minimal thermal quenching. The photoluminescence properties originate from Ce 3+ residing at two different crystallographic sites, a [BaO 9 ] distorted elongated square pyramid and a [CaO 6 ] trigonal prism. This combination results in an efficient, broad emission covering the blue to green region of the visible spectrum. Fabricating a simple dichromatic ultraviolet ( λ ex = 370 nm) pumped pc-wLED using Ba 2 CaB 2 Si 4 O 14 :Ce 3+ along with a commercially available red phosphor demonstrates full-visible-spectrum white light with high color rendering index ( R a > 90) and tunable correlated color temperature, showing the potential of this material for achieving high-quality LED-based lighting. 
    more » « less
  2. ; ; ; ; ; ; (, Micromachines)
    We have demonstrated full-color and white-color micro light-emitting diodes (μLEDs) using InGaN/AlGaN core-shell nanowire heterostructures, grown on silicon substrate by molecular beam epitaxy. InGaN/AlGaN core-shell nanowire μLED arrays were fabricated with their wavelengths tunable from blue to red by controlling the indium composition in the device active regions. Moreover, our fabricated phosphor-free white-color μLEDs demonstrate strong and highly stable white-light emission with high color rendering index of ~ 94. The μLEDs are in circular shapes with the diameter varying from 30 to 100 μm. Such high-performance μLEDs are perfectly suitable for the next generation of high-resolution micro-display applications. 
    more » « less
  3. ; ; ; ; ; ; (, Advanced Optical Materials)
    Abstract The all‐inorganic metal halide perovskite CsPbX3(X = Cl, Br, and I) has received extensive attention in the field of white light‐emitting diodes (WLEDs) due to its high luminous intensity and high color purity. However, the shortcoming of poor stability directly affects the luminous performance of the WLED devices and reduces their luminous efficiency, which has become an urgent problem to be solved. Here, three‐color lead halide perovskite phosphors (blue‐emitting CsPbBr3synthesized at 20 °C (CPB‐20), green‐emitting CsPbBr3‐80 (CPB‐80)/CsPbBr3:SCN−(CPB:SCN−), and red‐emitting PEA2PbBr4(PPB)/PEA2PbBr4:Mn2+(PPB:Mn2+)) with higher stability and luminous intensity are simultaneously prepared and applied in WLEDs. Density functional theory is used to optimize the structures of CsPbBr3and PEA2PbBr4, and to calculate the work function, optical properties, and charge density difference. Not only the WLED devices with three‐color lead halide perovskite phosphors are constructed, but also WLED devices from warm white to cold white are realized by tuning the ratio of the different emissions, and a superior color quality (color rendering index of 96) and ideal correlated color temperature (CCT of 9376 K) are achieved. This work will set the stage for exploring low‐cost, environmentally friendly, high‐performance WLEDs. 
    more » « less
  4. ; ; ; (, Advanced Photonics Research)
    All‐inorganic copper(I) halides have recently emerged as attractive alternatives to lead‐based halide perovskites and rare‐earth‐doped inorganics for light emission applications. Most of the newly discovered all‐inorganic Cu(I) halides demonstrate high‐efficiency blue emission albeit with unusually poor tunability of photoluminescence (PL) properties. This work reports the facile preparation of three new copper(I) halides based on the guanidinium cation: (CN3H6)3CuCl4, (CN3H6)7Cu3Br10·3(C3H7NO), and (CN3H6)7Cu3I10·3(C3H7NO). A comprehensive characterization of PL is presented for these novel materials, which have highly tunable, dual blue–yellow emission responsive to both excitation wavelength and vacuum annealing. These have remarkable photoluminescence quantum yield (PLQY) values of up to 34.6% and color‐rendering indices (CRI) up to 97% for tunable, single‐phase white light emission with correlated color temperatures (CCT) ranging from 4851 to 18 921 K, demonstrating the excellent potential of Cu(I) halides for light emission applications. 
    more » « less
  5. ; ; ; ; ; ; ; ; (, Journal of Materials Chemistry A)
    Only when the interfacial charge separation is enhanced and the CO 2 activation is improved, can the heterojunction nanocomposite photocatalyst be brought into full play for the CO 2 reduction reaction (CO 2 RR). Here, Er 3+ single atom composite photocatalysts were successfully constructed based on both the special role of Er 3+ single atoms and the special advantages of the SrTiO 3 :Er 3+ /g-C 3 N 4 heterojunction in the field of photocatalysis for the first time. As we expected, the SrTiO 3 :Er 3+ /g-C 3 N 4 (22.35 and 16.90 μmol g −1 h −1 for CO and CH 4 ) exhibits about 5 times enhancement in visible-light photocatalytic activity compared to pure g-C 3 N 4 (4.60 and 3.40 μmol g −1 h −1 for CO and CH 4 ). In particular, the photocatalytic performance of SrTiO 3 :Er 3+ /g-C 3 N 4 is more than three times higher than that of SrTiO 3 /g-C 3 N 4 . From Er 3+ fluorescence quenching measurements, photoelectrochemical studies, transient PL studies and DFT calculations, it is verified that a small fraction of surface doping of Er 3+ formed Er single-atoms on SrTiO 3 building an energy transfer bridge between the interface of SrTiO 3 and g-C 3 N 4 , resulting in enhanced interfacial charge separation. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (AC HAADF-STEM) and adsorption energy calculations demonstrated that the exposed Er single-atoms outside the interface on SrTiO 3 preferentially activate the adsorbed CO 2 , leading to the high photoactivity for the CO 2 RR. A novel enhanced photocatalytic mechanism was proposed, in which Er single-atoms play dual roles of an energy transfer bridge and activating CO 2 to promote charge separation. This provides new insights and feasible routes to develop highly efficient photocatalytic materials by engineering rare-earth single-atom doping. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email