Recent Advances in Multi-Site Luminescent Materials: Design, Identification and Regulation

Abstract

The development of novel phosphor materials with excellent performance and modification of their photoluminescence to meet the higher requirements for applications are the essential research subjects for luminescent materials. Multi-site luminescent materials with crystallographic sites for the activator ions that broaden the tunable range of luminescent spectra and even enhance the luminescent performance have attracted significant attention in the pursuit of high-quality luminescence for white light-emitting diodes. Here, we summarize multi-site luminescence characteristics based on the different kinds of host and activator ions, introduce the identifications of multi-site activator ions via optical analysis, provide a structural analysis and theoretical calculation methods, and introduce the regulation strategies and advance applications of multi-site phosphors. The review reveals the relationship between crystal structure and luminescent properties and discusses future opportunities for multi-site phosphors. This will provide guidance for the design and development of luminescent materials or other materials science.

Efficient, stable, broadband cyan‐emitting Ca‐substituted Ba9Lu2Si6O24:Eu2+ with multisite luminescence for NUV‐wLEDs

“…According to the structural analysis in the previous section, the new emission sub‐band can be attributed to Eu 2+ occupying Lu(Ca) sites, as shown in Figure 6(C). Therefore, a series of phosphors with four luminescence centers are synthesized by the nonequivalent substitution and the initial equivalent substitution of Eu 2+ , forming ultra‐wide emission spectra 42–44 . The new luminescence center Eu(Lu) is located in the center of [SiO4]‐[LuO6]‐[SiO4] network structure, which has stronger structure rigidity and higher symmetry 45,46 , resulting in the improvement of the quantum efficiency of phosphors.…”

“…Therefore, a series of phosphors with four luminescence centers are synthesized by the nonequivalent substitution and the initial equivalent substitution of Eu 2+ , forming ultra-wide emission spectra. [42][43][44] The new luminescence center Eu(Lu) is located in the center of [SiO4]-[LuO6]-[SiO4] network structure, which has stronger structure rigidity and higher symmetry 45,46 , resulting in the improvement of the quantum efficiency of phosphors. Similar to the sample x = 0.05, the samples x = 0.1, 0.15, 0.2, and 0.25 show broadband emission spectra, which can be divided into four different Gaussian sub-bands, which means that these samples have four luminescence centers, as shown in Figure S3.…”

Construction of thermally stable Tb3+-activated green-emitting phosphors: dual driving strategy of doping concentration and excitation wavelength

“…Many researchers have altered the structural characteristics of luminous materials in recent years by using them in various applications, including power meter sensors, WLEDs, optical thermometers, and pressure sensors. [1][2][3] Thermal quenching (TQ) has been a major limiting factor for conventional solidstate lighting. [4][5][6][7][8][9] The TQ characteristics of the luminescent material are required to meet specific requirements depending on its intended application.…”

Charge Transfer and Charge Trapping Processes in Ca- or Al-Co-doped Lu2SiO5 and Lu2Si2O7 Scintillators Activated by Pr3+ or Ce3+ Ions

“…All the abovementioned materials are excellent candidates for the detection of gamma rays in both positron emission tomography (PET), a very powerful medical imaging method to monitor metabolism, blood flow, or neurotransmission [ 7 ], and high energy calorimetry [ 2 , 8 ]. LYSO:Ce crystals are currently used in scintillation detectors in PET scanners, and various co-doping schemes have been reported in the last decade to further improve their performance [ 2 , 9 , 10 ]. In particular, co-doping LSO:Ce with divalent Ca 2+ or Mg 2+ ions has been shown to eliminate shallow electron traps and decrease the scintillation decay time from ~43 ns to ~30 ns while maintaining a high light output [ 8 , 11 , 12 ].…”