Anomalous tunable visible to near infrared emission in the Mn2+-doped spinel MgGa2O4 and room-temperature upconversion in the Mn2+ and Yb3+-codoped spinel

Song, Enhai; Wang, J. L.; Yu, Dechao; Ye, Shi; Zhang, Q. Y.

doi:10.1039/c4tc01681e

Cited by 41 publications

(34 citation statements)

References 30 publications

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“…Obviously, the formation of Mn 2+ Mn 2+ dimers requires a the critical distance of ≈5 Å between two Mn 2+ ions . On average, higher doping concentration leads to lower distance among the activators.…”

Section: Resultsmentioning

confidence: 99%

“…However, emissions from the assumed superexchange reaction occurs outside the sensitivity range of the human eye, so it is irrelevant for applications in illumination or display . Furthermore, because a significant part of the incoming excitation energy is converted to infrared emission in this system, the output in visible (Vis) luminescence is comparably low …”

Section: Introductionmentioning

confidence: 99%

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Wavelength‐Tunability and Multiband Emission from Single‐Site Mn²⁺ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions

Song

Wang

et al. 2017

Advanced Optical Materials

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In modern phosphor materials, in contrast to single‐band emission, simultaneous photoluminescence through two or more emission bands enables broad and tailorable emission color, but requires fine control of activator precipitation on specific crystallographic sites. This presents a major obstacle in the design of tunable emitters, since dedicated control of site occupancy is rarely possible. Here, a new paradigm of tunability is considered, which overcomes this limitation. It is demonstrated in CaO:Mn2+ that single‐ and dual‐band emission can be generated by involving only a single type of crystallographic sites. This enables tailoring of the emission color alone through dopant concentration. The two emission bands exhibit different spectral, dynamic, and thermal characteristics, but very similar excitation spectra. While the variations in thermal quenching provide a tool for tunability, the variations in decay behavior suggest interesting potential for lifetime‐multiplexing and coding. Energy transfer is observed between the two emission bands, using time‐resolved emission spectra. From the analysis of crystal structure, spectral data, electron paramagnetic resonance analyses, and density functional theory calculations analyses, it is found that the emission bands at ≈600 and 660 nm originate from isolated Mn2+ ions and superexchange reactions in Mn2+ Mn2+ dimers, respectively.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wavelength‐Tunability and Multiband Emission from Single‐Site Mn²⁺ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions

Song

Wang

et al. 2017

Advanced Optical Materials

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“…The authors provided concrete evidence that lanthanide-doped nanocrystals have exceptionally high photostability against laser beam illumination (100-170 W cm À2 ) for 4 h. In a recent work by the same group, they suggested that the high photostability against photobleaching is a general characteristic of the UC nanocrystals, regardless of whether different host materials or core-shell strategies are implemented. 78 In both T 1g (G) -6 A 1g (S) [188][189][190] cases, superior photophysical stability of UC nanocrystals was further verified under high power density excitation up to 3 Â 10 6 W cm À2 (Fig. A high power density of 10 6 W cm À2 can be generated by focusing laser beam into a tiny volume with a diameter of less than 1 mm.…”

Section: Excitation By Continuous-wave (Cw) Lasermentioning

confidence: 99%

Probing the nature of upconversion nanocrystals: instrumentation matters

et al. 2015

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Probing the nature of nanocrystalline materials such as the surface state, crystal structure, morphology, composition, optical and magnetic characteristics is a crucial step in understanding their chemical and physical performance and in exploring their potential applications. Upconversion nanocrystals have recently attracted remarkable interest due to their unique nonlinear optical properties capable of converting incident near-infrared photons to visible and even ultraviolet emissions. These optical nanomaterials also hold great promise for a broad range of applications spanning from biolabeling to optoelectronic devices. In this review, we overview the instrumentation techniques commonly utilized for the characterization of upconversion nanocrystals. A considerable emphasis is placed on the analytical tools for probing the optical properties of the luminescent nanocrystals. The advantages and limitations of each analytical technique are compared in an effort to provide a general guideline, allowing optimal conditions to be employed for the characterization of such nanocrystals. Parallel efforts are devoted to new strategies that utilize a combination of advanced emerging tools to characterize such nanosized phosphors.

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“…It was suggested that tetrahedrally (weak crystal field) and octahedrally (strong crystal field) coordinated Mn 2+ ions tend to give rise to green and orange-to-red emission, respectively. [25][26][27][28] We hypothesized that a continued increase in Ca 2+ doping concentration might lead to variations in the crystal field around Mn 2+ ions. To prove this, we performed extended www.advopticalmat.de X-ray absorption fine structure (EXAFS) measurement of NaGdF 4 :Ca/Mn (x/30 mol%) nanoparticles (x = 5 and 40) ( Figure 3b).…”

Section: Tuning Long-lived Mn(ii) Upconversion Luminescence Through Amentioning

confidence: 99%

Tuning Long‐Lived Mn(II) Upconversion Luminescence through Alkaline‐Earth Metal Doping and Energy‐Level Tailoring

Liu

Qin

et al. 2019

Advanced Optical Materials

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Crystal‐site engineering of hexagonal‐phase NaGdF4:Mn through alkaline‐earth metal (A2+) doping is used to tune the upconversion luminescence of the Mn2+ dopants. Experimental and calculated results show the ability of A2+ doping to alter the occupancy site of Mn2+ ion from Na+ to Gd3+, thus enabling an emission change from green (520 nm) to yellow (583 nm) upon excitation at 980 nm. The yellow emission of Mn2+ shows a long emission lifetime of 65 ms, more than three times longer than the green emission of Mn2+ (20 ms). The combination of tunable long‐lived Mn2+ emission with lanthanide emission at a single‐particle level provides a convenient route to triple transient upconversion color codes upon dynamic excitation, which offers an attractive optical feature particularly suitable for efficient document encoding.

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Anomalous tunable visible to near infrared emission in the Mn²⁺-doped spinel MgGa₂O₄ and room-temperature upconversion in the Mn²⁺ and Yb³⁺-codoped spinel

Abstract: In contrast to common visible emission, an anomalous near-infrared emission at 790 nm has been demonstrated in spinel structure MgGa2O4:Mn2+ with heavy Mn2+ doping.

Cited by 41 publications

References 30 publications

Wavelength‐Tunability and Multiband Emission from Single‐Site Mn²⁺ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions

Wavelength‐Tunability and Multiband Emission from Single‐Site Mn²⁺ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions

Probing the nature of upconversion nanocrystals: instrumentation matters

Tuning Long‐Lived Mn(II) Upconversion Luminescence through Alkaline‐Earth Metal Doping and Energy‐Level Tailoring

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Anomalous tunable visible to near infrared emission in the Mn2+-doped spinel MgGa2O4 and room-temperature upconversion in the Mn2+ and Yb3+-codoped spinel

Abstract: In contrast to common visible emission, an anomalous near-infrared emission at 790 nm has been demonstrated in spinel structure MgGa2O4:Mn2+ with heavy Mn2+ doping.

Cited by 41 publications

References 30 publications

Wavelength‐Tunability and Multiband Emission from Single‐Site Mn2+ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions

Wavelength‐Tunability and Multiband Emission from Single‐Site Mn2+ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions

Probing the nature of upconversion nanocrystals: instrumentation matters

Tuning Long‐Lived Mn(II) Upconversion Luminescence through Alkaline‐Earth Metal Doping and Energy‐Level Tailoring

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Product

Resources

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Anomalous tunable visible to near infrared emission in the Mn²⁺-doped spinel MgGa₂O₄ and room-temperature upconversion in the Mn²⁺ and Yb³⁺-codoped spinel

Wavelength‐Tunability and Multiband Emission from Single‐Site Mn²⁺ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions

Wavelength‐Tunability and Multiband Emission from Single‐Site Mn²⁺ Doped CaO Through Antiferromagnetic Coupling and Tailored Superexchange Reactions