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
  • A novel reversible fluorescent probe for the highly sensitive detection of nitro and peroxide organic explosives using electrospun BaWO 4 nanofibers
Title: A novel reversible fluorescent probe for the highly sensitive detection of nitro and peroxide organic explosives using electrospun BaWO 4 nanofibers
Fabrication of highly stable, reversible, and efficient portable sensors for the detection of explosives for safety and security is challenging due to the robustness of the currently available detection tools, limiting their mass deployment to the explosion prone areas. This paper reports a new direction towards the sensing of nitro- and peroxide-based explosives using highly stable rare-earth-doped BaWO 4 nanofibers with remarkable sensitivity and reversibility. BaWO 4 nanofibers doped with Tb 3+ and Eu 3+ ions are fabricated through a sol–gel electrospinning process, and their emission characteristics and application as a fluorescent probe for the sensing of 2-nitrotoluene and H 2 O 2 , explosive taggants representing a broad class of explosives, are studied in detail. Scheelite structured BaWO 4 nanofibers exhibit excellent luminescence characteristics, and the rare-earth ion doping in the polycrystalline BaWO 4 nanofibers is tailored to achieve blue, green, red, and white light emissions. These nanofibers are extremely sensitive to 2-nitrotoluene and H 2 O 2 with rapid response time, and sensitivity is observed within the range of 1–400 ppb and 1–10 ppm, towards 2-nitrotoluene and H 2 O 2 , respectively. The fluorescence quenching of BaWO 4 nanofibers in the presence of 2-nitrotoluene and H 2 O 2 is exponential with the quenching constants up to 1.73 × 10 6 and 2.73 × 10 4 L mol −1 , respectively, which are significantly higher than those of most of the fluorescent probes based on metal–organic frameworks and conjugated organic materials. After exposing to 2-nitrotoluene, the luminescence of the nanofibers is retained completely upon heating at 120 °C for 10 min and the sensory response is retained as fresh nanofibers, and currently available fluorescent explosive sensors could not achieve such a recovery. The high sensitivity and selectivity of scalable rare-earth-doped BaWO 4 nanofibers provide a new platform for the simultaneous detection of two classes of explosives.  more » « less
Award ID(s):
1626376
PAR ID:
10172646
Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
Journal of Materials Chemistry C
Volume:
7
Issue:
47
ISSN:
2050-7526
Page Range / eLocation ID:
14949 to 14961
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; ; et al (, Journal of Materials Chemistry A)
    The sorption properties of [Zr 6 O 4 (OH) 4 (NH 3 + -BDC) 6 ]Cl 6 · x H 2 O ( MOR-1 ) and H 16 [Zr 6 O 16 (H 2 PATP) 4 ]Cl 8 · x H 2 O ( MOR-2 ) towards ReO 4 − and TcO 4 − were studied in detail. Both MOR-1 and MOR-2 are very effective sorbents for ReO 4 − and TcO 4 − anions, with MOR-2 showing the highest sorption capacity (up to 4.1 ± 0.4 mmol g −1 ) among the known metal organic materials. Importantly, the exceptional sorption capacity of MOR-2 is retained even under conditions simulating acidic nuclear waste. In addition, MOR-1 and MOR-2 exhibit selective luminescence ReO 4 − sensing properties, demonstrated for the first time for MOF materials. 
    more » « less
  2. ; ; ; ; ; ; ; ; (, RSC Advances)
    Fluorides are promising host materials for optical applications. This paper reports the photoluminescent (PL) and cathodoluminescent (CL) characteristics of barium hexafluorogermanate BaGeF 6 nanowires codoped with Ce 3+ , Tb 3+ and Sm 3+ rare earth ions, produced by a solvothermal route. The synthesized BaGeF 6 nanowires exhibit uniform morphology and size distribution. X-ray diffraction divulges the one-dimensional growth of crystalline BaGeF 6 structure, with the absence of any impurity phases. Visible luminescence is recorded from the nanowires in green and red regions, when the nanowires are codoped with Ce 3+ /Tb 3+ , and Ce 3+ /Tb 3+ /Sm 3+ , respectively, under a UV excitation source. The PL emission from the codoped BaGeF 6 nanowires, when excited by a 254 nm source, originates from the efficient energy transfer bridges between Ce 3+ , Tb 3+ and Sm 3+ ions. The decay time of the visible luminescent emission from the nanowires is in the order of subnanoseconds, being one of the shortest decay time records from inorganic scintillators. The CL emission from the BaGeF 6 nanowires in the tunable visible range reveals their potential use for the detection of high-energy radiation. The PL emissions are sensitive to H 2 O 2 at low concentrations, enabling their high-sensitivity detection of H 2 O 2 using BaGeF 6 nanowires. A comparison with BaSiF 6 nanowires is made in terms of decay time and its sensitivity towards H 2 O 2 . 
    more » « less
  3. ; ; ; (, New Journal of Chemistry)
    New optical materials with efficient luminescence and scintillation properties have drawn a great deal of attention due to the demand for optoelectronic devices and medical theranostics. Their nanomaterials are expected to reduce the cost while incrementing the efficiency for potential lighting and scintillator applications. In this study, we have developed praseodymium-doped lanthanum hafnate (La 2 Hf 2 O 7 :Pr 3+ ) pyrochlore nanoparticles (NPs) using a combined co-precipitation and relatively low-temperature molten salt synthesis procedure. XRD and Raman investigations confirmed ordered pyrochlore phase for the as-synthesized undoped and Pr 3+ -doped La 2 Hf 2 O 7 NPs. The emission profile displayed the involvement of both the 3 P 0 and 1 D 2 states in the photoluminescence process, however, the intensity of the emission from the 1 D 2 states was found to be higher than that from the 3 P 0 states. This can have a huge implication on the design of novel red phosphors for possible application in solid-state lighting. As a function of the Pr 3+ concentration, we found that the 0.1%Pr 3+ doped La 2 Hf 2 O 7 NPs possessed the strongest emission intensity with a quantum yield of 20.54 ± 0.1%. The concentration quenching, in this case, is mainly induced by the cross-relaxation process 3 P 0 + 3 H 4 → 1 D 2 + 3 H 6 . Emission kinetics studies showed that the fast decaying species arise because of the Pr 3+ ions occupying the Hf 4+ sites, whereas the slow decaying species can be attributed to the Pr 3+ ions occupying the La 3+ sites in the pyrochlore structure of La 2 Hf 2 O 7 . X-ray excited luminescence (XEL) showed a strong red-light emission, which showed that the material is a promising scintillator for radiation detection. In addition, the photon counts were found to be much higher when the NPs are exposed to X-rays when compared to ultraviolet light. Altogether, these La 2 Hf 2 O 7 :Pr 3+ NPs have great potential as a good down-conversion phosphor as well as scintillator material. 
    more » « less
  4. ; ; ; ; (, Dalton Transactions)
    A new synthetic route to access pristine and rare-earth-doped BaFBr nanocrystals is described. Central to this route is an organic–inorganic hybrid precursor of formula Ba 5 (CF 2 BrCOO) 10 (H 2 O) 7 that serves as a dual-halogen source. Thermolysis of this precursor in a mixture of high-boiling point organic solvents yields spherical BaFBr nanocrystals (≈20 nm in diameter). Yb:Er:BaFBr nanocuboids (≈26 nm in length) are obtained following the same route. Rare-earth-doped nanocrystals display NIR-to-visible photon upconversion under 980 nm excitation. The temperature-dependence of the green emission from Er 3+ may be exploited for optical temperature sensing between 150 and 450 K, achieving a sensitivity of 1.1 × 10 −2 K −1 and a mean calculated temperature of 300.9 ± 1.5 K at 300 K. The synthetic route presented herein not only enables access to unexplored upconverting materials but also, and more importantly, creates the opportunity to develop solution-processable photostimulable phosphors based on BaFBr. 
    more » « less
  5. ; ; ; ; ; (, Materials Advances)
    The development of macroscopic aerogels from 1D systems, such as nanofibers, has resulted in a novel pathway to obtain porous and lightweight architectures. In this work, bright green, red, and tunable color emitting aerogels were obtained with luminescent nanofibers as the precursor system. A simple, low cost, and environmentally friendly process is followed where luminescent fillers are encapsulated within fibers which were subsequently freeze-dried to form 3D aerogels and sponge-like structures. Moreover, the aerogels/sponge-like structures show higher photoluminescence intensity than the fiber mats due to an increase of porosity which provides higher and direct interaction with the fillers and therefore an efficient light absorption resulting in higher luminescence. Manganese doped zinc germanate (Mn: Zn 2 GeO 4 ) nanorods and chromium doped zinc gallate (Cr: ZnGa 2 O 4 ) nanoparticles were used as the source of green and red emissions respectively. By precisely adjusting the stoichiometric ratios of nanorods and nanoparticles within the nanofibers, a broad spectrum output is obtained from the final aerogels. We foresee that these types of photoluminescent aerogels have promising potential applications in a variety of fields such as display devices, solid-state lighting, sensors, etc. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email