Achieving high thermal stability of different rare-earth ions in a single matrix host via the manipulation of the local structure by a solid solution

Luminescence Properties and Energy Transfer in SrLa2Sc2O7 Co-Doped with Bi3+/M (M = Eu3+, Mn4+, or Yb3+)

Series of Eu³⁺/Mn⁴⁺/Yb³⁺-doped SrLa₂Sc₂O₇:Bi³⁺ (SLSO: Bi³⁺) were synthesized by a high-temperature solid-state method, and the energy transfer of Bi³⁺→Eu³⁺/Mn⁴⁺/Yb³⁺ was observed. Under ultraviolet radiation, a 550 nm emission peak was observed, which is attributed to Bi³⁺ occupying the Sr²⁺/La³⁺ sites. Additionally, the other peaks were found to be 615, 707, and 980 nm, which are assigned to the Re³⁺ (Eu³⁺ and Yb³⁺) and Mn⁴⁺ occupying two different cationic sites. An obvious energy transfer (ET) from Bi³⁺ to Eu³⁺/Mn⁴⁺/Yb³⁺ was observed, and the tunable color, emitting from yellow to red, was obtained; the ET efficiency was about 86.2%, 78.6%, and 27.5% in SLSO, respectively. We found that the large overlap area between the emission spectrum of the sensitizer and the excitation spectrum of the activator could produce efficient energy transfer, which provided the idea for designing experiments in the future for some highly efficient energy transfer processes.

Inorganic Lanthanide Compounds with f-d Transition: From Materials to Electroluminescence Devices

With the rapid development of the panel display market, demand for efficient light emitters as active layers in electroluminescence (EL) devices has significantly increased. Luminescent inorganic lanthanide compounds (ILCs) with a characteristic f-d transition are particularly preferred for EL devices because of their high photoluminescent quantum yield, short excited-state lifetime, tunable emission spectra, and high thermal stability. In this Perspective, we first present an overview of inorganic lanthanide compounds with an emphasis on the mechanisms and characteristics of f-d emission. Then, the comprehensive advances of lanthanide element-doped inorganic compounds for EL study in recent decades are summarized. Moreover, the recent progress in directly employing ILCs for EL applications and rational improvement strategies in EL performance are highlighted. Last, we summarize the current challenges and opportunities of ILC-based EL devices as well as future improvement directions.

Tailored Up-conversion Luminescence Output of Al-modulated KYbF4: Er3+ Nanocrystals for Low-Temperature Sensor

The up-conversion features of lanthanide-doped nanocrystals endow them promising application in optical encoding, optical temperature sensing, bioimaging, diagnostics, and therapeutics. Here, tailoring the local structure to enhance the up-conversion luminescence...

Local Structure Modulation-Induced Highly Efficient Red-Emitting Ba2Gd1-xYxNbO6:Mn4+ Phosphors for Warm WLEDs

Modulating the crystal field environment around the emitting ions is an effective strategy to improve the luminescence performance of the practical effective phosphor materials. Here, smaller Y³⁺ ions are introduced into substituting the Gd³⁺ sites in Ba₂GdNbO₆:Mn⁴⁺ phosphor to modify the optical properties, including the enhanced luminescence intensity, redshift, and longer lifetime of the Mn⁴⁺ ions. The substitution of smaller Y³⁺ ions leads to lattice contraction and then strengthens pressure on the local structure, enhances lattice rigidity, and suppresses nonradiative transition. Moreover, the prototype phosphor-converted light-emitting diode (LED) demonstrates a continuous change photoelectric performance with a correlated color temperature of 4883-7876 K and a color rendering index of 64.1-83.2, suggesting that it can be one of the most prospective fluorescent materials applied as a warm red component for white LEDss. Thus, the smaller ion partial substitution can provide a concise approach to modulate the crystal field environment around the emitting ions for excellent luminescence properties of phosphors toward the modern artificial light.