Cr3+ sensitized near infrared emission in Al2O3:Cr,Nd/Yb phosphors

Tawalare, P.K.; Bhatkar, V.B.; Omanwar, S. K.; Moharil, S. V.

doi:10.1016/j.jallcom.2019.03.201

Cited by 24 publications

(13 citation statements)

References 54 publications

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“…A different method, used more in general for the preparation of bright lanthanide-based phosphors, relies on codoping Ln 3+ and other ions such as Bi 3+ , − Cr 3+ , − Mn 3/4+ , or Ce 3+ . − These ions possess allowed electronic transitions so that they can absorb the optical energy in a broadband fashion and funnel it to the emitting Ln 3+ centers. Although the energy of those allowed transitions is dependent on the crystal field experienced by the ion, the related absorption bands generally fall at the shorter-wavelength end of the visible spectrum, hence limiting the applicability of this strategy when absorption approaching near-infrared (NIR) is sought after.…”

Section: Introductionmentioning

confidence: 99%

Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence

2020

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The spectrally narrow, long-lived luminescence of lanthanide ions makes optical nanomaterials based on these elements uniquely attractive from both a fundamental and applicative standpoint. A highly coveted class of such nanomaterials is represented by colloidal lanthanide-doped semiconductor nanocrystals (LnSNCs). Therein, upon proper design, the poor light absorption intrinsically featured by lanthanides is compensated by the semiconductor moiety, which harvests the optical energy and funnel it to the luminescent metal center. Although a great deal of experimental effort has been invested to produce efficient nanomaterials of that sort, relatively modest results have been obtained thus far. As of late, halide perovskite nanocrystals have surged as materials of choice for doping lanthanides, but they have non-negligible shortcomings in terms of chemical stability, toxicity, and light absorption range. The limited gamut of currently available colloidal LnSNCs is unfortunate, given the tremendous technological impact that these nanomaterials could have in fields like biomedicine and optoelectronics. In this Review, we provide an overview of the field of colloidal LnSNCs, while distilling the lessons learnt in terms of material design. The result is a compendium of key aspects to consider when devising and synthesizing this class of nanomaterials, with a keen eye on the foreseeable technological scenarios where they are poised to become front runners.* In their book "Understanding Chemistry", Pimentel and Sprately commented how "Lanthanum has only one important oxidation state in aqueous solution, the +3 state. With few exceptions, this tells the whole boring story about the other 14 Lanthanides". Scheme 1. Aspects discussed in this Review about colloidal Ln 3+ -doped semiconductor nanocrystals (LnSNCs). * In 1798, B. M. Tassaert reported the first coordination compound of cobalt and ammonia without, however, fully understanding the material. Passing through S. M. Jörgensen's chain theory to explain metal complexes, it was only in 1893 that A. Werner finally realized the existence of a principal (oxidation state) and auxiliary (coordination number) for the metal in that "odd" class of complex compounds (as Tassaert first referred to them).* This last statement is only partially true. There are slight changes in the position of the 4f-4f emission lines of Ln 3+ depending on the coordination environment of the ion. The extent of such shifts is of up to a few hundred wavenumbers at most and they occur because of the so-called nephelauxetic effect, where changes in the bond length between Ln 3+ and the surrounding anions result in variation of 4f electronic distribution. * A Lewis acid is a species that accepts lone electron pairs from a donor species (Lewis bases). The less (more) the Lewis acid is polarizable, the harder (softer) its acid character is, according to the hard soft acids bases (HSAB) theory. This acidity can be regarded as a measure of how "thirsty" for electrons a species is.* Preliminary information a...

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Section: Introductionmentioning

confidence: 99%

Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence

2020

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“…The pc‐LED produced the NIR light output power of 26 mW at 100 mA drive current . Actually, Cr 3+ and Yb 3+ codoped NIR phosphors have been studied mostly as spectral converters for silicon solar cells applications . For this application, the phosphors were designed to have highly efficient energy transfer from Cr 3+ to Yb 3+ , and, therefore, the dominant emission of Yb 3+ located around 1000 nm matching well the spectral response of Si solar cell.…”

Section: Introductionmentioning

confidence: 99%

Efficient Super Broadband NIR Ca₂LuZr₂Al₃O₁₂:Cr³⁺,Yb³⁺ Garnet Phosphor for pc‐LED Light Source toward NIR Spectroscopy Applications

Zhang

et al. 2020

Advanced Optical Materials

198

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Super broadband near‐infrared (NIR) phosphor converted light‐emitting diodes (pc‐LEDs) are future light sources in NIR spectroscopy applications such as food testing. At present, a few blue LED excitable super broadband NIR phosphors (bandwidth > 300 nm) have been developed producing the NIR output powers below 26 mW at 100 mA input current after LED packaging. Here, an efficient super broadband NIR phosphor achieved by doping Yb3+ is reported in the NIR Ca2LuZr2Al3O12:Cr3+ (CLZA:Cr3+) garnet phosphor developed previously. Benefited from the superposition of Cr3+ emission and highly efficient Yb3+ emission excited by energy transfer from Cr3+, the codoped CLZA:Cr3+,Yb3+ phosphor shows a bandwidth of 320 nm and an internal quantum efficiency of 77.2% both higher than that (150 nm and 69.1%) of singly doped CLZA:Cr3+ phosphor. The codoped phosphor converts LED produced 41.8 mW NIR output at 100 mA input current. The pc‐LED as a light source is also well applied to the NIR transmission spectra measurement of water. The results indicate the great potential of CLZA:Cr3+,Yb3+ phosphor in super broadband NIR pc‐LED applications.

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“…In the case of Al 2 O 3 host material the strong crystal field strength is expected. Therefore narrow 2 E→ 4 A 2 emission band at 696 nm is dominant in the spectrum [17]. It can be noticed that the increase of the temperature causes the reduction of luminescent intensity of both emissions, pointing to the phenomenon of luminescence thermal quenching.…”

Section: Resultsmentioning

confidence: 92%

“…This wavelength of irradiation provides the emission of Cr 3+ ions coming from the d-d electronic transition from excited states 2 E g and 4 T 2 to the ground state 4 A 2 . The 2 E g → 4 A 2 and 4 T 2 → 4 A 2 electronic transitions lead to the generation of two emission bands, namely the narrow emission line with the maximum at 695 nm and the broad emission band, centred at 709 nm, respectively [17]. As it is well known, transition metal ions are strongly susceptible to luminescence thermal quenching.…”

Section: Resultsmentioning

confidence: 99%

“…The energy at which this inter-section occurs, called activation energy, describes how efficient luminescence of transition metal ion will be quenched at elevated temperatures. In the case of Cr 3+ ions, which are one of the most extensively investigated, the 2 E excited state parabola intersects with the 4 T 2 one [11,12,[17][18][19][20]. Therefore at higher temperatures the non-radiative depopulation leads to the quenching of Cr 3+ emission intensity.…”

Section: Resultsmentioning

confidence: 99%

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ZrB2 matrix composites with Cr3+/Nd3+ doped Al2O3 luminescent nanoparticles for non-contact temperature sensing

Naughton-Duszová¹,

Marciniak²,

Dubiel³

et al. 2020

PAC

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The effect of the addition of Cr 3+ /Nd 3+ doped Al 2 O 3 nanoparticles (Al 2 O 3 co-doped with 1% Cr 3+ and 1% Nd 3+ ions) on the mechanical and luminescent properties of ZrB 2 ceramic composites was investigated. ZrB 2 based composites with addition of 8, 16 and 32 wt.% of alumina nanoparticles were prepared by spark plasma sintering (SPS). Microstructure characteristics were studied by scanning electron microscopy (SEM), elastic modulus by ultrasonic wave transition method, hardness and fracture toughness by the Vickers indentation methods. The addition of alumina nanoparticles had positive effect on the mechanical properties of the composites. Thus, the hardness increased from 14.5 to 16.2 GPa and the fracture toughness from 3.91 to 5.89 MPa•m 1/2 in comparison to the values of the monolithic ZrB 2 system. The composite with the highest additive content showed evident luminescent character and the increase of the temperature caused a reduction of luminescent intensity. This is the first report which shows luminescent properties of ZrB 2 composites. Moreover, for the first time, luminescent properties of Cr 3+ ions were used to develop ZrB 2 matrix composites with Cr 3+ /Nd 3+ doped Al 2 O 3 particles with the self-temperature readout functionality via luminescent thermometry.

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Cr3+ sensitized near infrared emission in Al2O3:Cr,Nd/Yb phosphors

Cited by 24 publications

References 54 publications

Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence

Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence

Efficient Super Broadband NIR Ca₂LuZr₂Al₃O₁₂:Cr³⁺,Yb³⁺ Garnet Phosphor for pc‐LED Light Source toward NIR Spectroscopy Applications

ZrB2 matrix composites with Cr3+/Nd3+ doped Al2O3 luminescent nanoparticles for non-contact temperature sensing

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Cr3+ sensitized near infrared emission in Al2O3:Cr,Nd/Yb phosphors

Cited by 24 publications

References 54 publications

Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence

Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence

Efficient Super Broadband NIR Ca2LuZr2Al3O12:Cr3+,Yb3+ Garnet Phosphor for pc‐LED Light Source toward NIR Spectroscopy Applications

ZrB2 matrix composites with Cr3+/Nd3+ doped Al2O3 luminescent nanoparticles for non-contact temperature sensing

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Efficient Super Broadband NIR Ca₂LuZr₂Al₃O₁₂:Cr³⁺,Yb³⁺ Garnet Phosphor for pc‐LED Light Source toward NIR Spectroscopy Applications