A novel Cr3+-doped stannate far red phosphor for plant lighting: structure evolution, broad-narrow spectrum tuning and application prospect

Chen

Advanced Optical Materials

et al. 2023

Applications in near‐infrared (NIR) have been explored significantly in many fields, including bioimaging, night vision, plant growth, and chemical analysis. Different emission profiles are required within the same industry. Developing luminescent materials with different tuning methods is reliable for controlling the NIR regions (NIR‐I, 700–1000 nm; NIR‐II, 1000–1700 nm). Spinel phosphors are promising candidates due to their ability to modulate the crystal field. Understanding the parameters that influence the degree of inversion in spinel compounds is crucial to harness the variability of the spinel structure. Cr3+ and Ni2+ are ideal activators for NIR‐I and NIR‐II emissions, respectively. However, there is a need for phosphors that emit in the NIR‐II region when excited by visible light. Although the energy transfer method combining two activators is considered, this review focuses on different types of spinel structures, discussing their types and common strategies to tune the host structure. The goal is to achieve desired shift and broadness of the entire NIR spectrum, highlighting the importance of spectrum tuning for practical applications.

Section: Nir-i Emissionmentioning

confidence: 99%

Section: Cosubstitution (Same System)mentioning

confidence: 99%

Section: Cosubstitution (Same System)mentioning

confidence: 99%

Section: Cosubstitution (Same System)mentioning

confidence: 99%

Section: Cosubstitution (Same System)mentioning

confidence: 99%

See 3 more Smart Citations

Tunable Spinel Structure Phosphors: Dynamic Change in Near‐Infrared Windows and Their Applications

Chen

Advanced Optical Materials

et al. 2023

Advanced Optical Materials

Novel Cr³⁺‐Doped Garnet Phosphor with Broadband Efficient Far‐Red Emission for Photochrome Matching Plant‐Lighting

Dai,

Zou,

Zhang

et al. 2023

Cr3+‐doped phosphors are highly recognized in various fields for their remarkable luminous efficiency and spectral flexibility, including modern agriculture and horticulture. However, the shortage of suitable Cr3+‐doped phosphors for far‐red LED devices has inhibited their popularization in plant lighting. Herein, an innovative Cr3+‐doped phosphor Ca2YAl3Ge2O12:Cr3+ (CYAG:Cr3+), achieving a broad far‐red emission at 770 nm upon 450 nm blue light excitation is designed. The optimal CYAG:Cr3+ phosphor exhibits a high internal quantum yield of 78.2% and low thermal‐quenching behavior of 85%@373 K. Thus, the fabricated phosphor‐converted LEDs (pc‐LEDs) for plant far‐red lighting have a high output power of 33.3 mW and photovoltaic conversion efficiency of 11.5% at 100 mA. The potential of CYAG:Cr3+ in plant lighting is assessed by supplementing the far‐red lighting of Italian lettuce with fabricated pc‐LEDs, and the biomass of Italian lettuce is significantly increased by 33%. The successful development of CYAG:Cr3+ phosphors provides a high‐quality option for plant far‐red light devices and further stimulates the development of new Cr3+‐doped plant‐lighting phosphors.

Laser & Photonics Reviews

Cr³⁺‐Cr³⁺ Ion Pair Induced Fast Energy Migration in Cr³⁺ Doped Na‐β‐Al₂O₃ Ultra‐Wide Near‐Infrared Phosphors for NIR Spectroscopy Application

Pang,

Wang,

Yan

et al. 2023

Technological progress has promoted the development of ultra‐wide near‐infrared (NIR) luminescent materials as a new NIR light source. The ultra‐wide near‐infrared (NIR) emission in Na(Al,Ga)11O17:xCr3+(NAGO:xCr3+) phosphors is achieved by constructing unique Cr3+‐Cr3+ion pair confined structure. The Cr3+‐Cr3+ ion pairs can be observed at a low concentration of Cr3+ ions(x = 0.04), the increase of Ga3+ ion would promote the formation of Cr3+‐Cr3+ ion pairs, thereby effectively enhancing the energy migration process from high‐energy Cr3+ ions to low‐energy Cr3+ ones. Herein, the full width at half maximum can be finely adjusted in a wide range from 17 to 223 nm, while the emission peaks can shift from 704 to 860 nm. NAGO:xCr3+ exhibits the longest‐wavelength emission in the known Cr3+‐doped galliates and aluminates phosphors. The study further reveals the inherent mechanism of affect on the photoluminescence properties for Cr3+‐Cr3+ ion pairs. The quantum efficiency of optimal NaAl11O17:0.004Cr3+ (sharp emission) and NaGa11O17:0.02Cr3+(ultra‐wide emission) samples reaches 87.6% and 46.6% with high thermal stability (84.47% and 67.52%@150 °C), respectively. The comprehensive properties are excellent among known phosphors with similar property. Multifunctional applications of NAGO:xCr3+ in agricultural production, quality inspection, and imaging fields are also demonstrated.