Red-Emitting SrGa₂O₄:Cu²⁺ Phosphor with Super-Long Persistent Luminescence

Abstract

The red afterglow of current rare-earth-activated long persistent luminescence (LPL) phosphors is largely still less than 6 h, in contrast to the 20 or 30 h long blue-or green-emitting ones, becoming the main obstacle to realize their multiscenario applications in practice. Herein, we report a rare-earth-free redemitting LPL phosphor SrGa 2 O 4 :Cu 2+ that can exhibit an afterglow at about 622 nm lasting over 30 h, which can largely match with the luminance of current blue-or green-emitting LPL phosphors. We find that the Cu 2+ ion could be charged by ultraviolet light from 280 to 420 nm, and the emission has a very broad band with a full width at half-maximum of about 150 nm. Combining the thermoluminescence measurement and the first-principles calculation, we find that the O vacancies and the −1 charged Ga vacancies could store the holes and contribute to the LPL of SrGa 2 O 4 :Cu 2+ . Our results may dramatically promote and expand its potential applications and stimulate the research of the multicolor LPL phosphors in future.

From Ancient Blue Pigment to Unconventional NIR Phosphor: A Thermal-Stable Near-Infrared I/II Broadband Emission from Ca1–xSrxCuSi4O10 Solid Solution

“…Cu 2+ with 3d 9 configuration could show green emission in CaF 2 , orange emission in SrZrO 3 , red emission in SrGa 2 O 4 , and infrared emission in YGaO 3 , Ca 10 (PO4) 6 (OH) 2 , and KZnF 3 . 22 Generally, the d-d transition of Cu 2+ in most of the reported phosphors would produce an infrared emission, since the crystal field splitting exerted on the Cu 2+ ion is usually weak.…”

“…As an alternative, Cu 2+ is an eco-friendly and chemically stable emitting center with high absorption efficiency, strong NIR luminescence, good chemical and photochemical stability. Cu 2+ with 3 d 9 configuration could show green emission in CaF 2 , orange emission in SrZrO 3 , red emission in SrGa 2 O 4 , and infrared emission in YGaO 3 , Ca 10 (PO4) 6 (OH) 2 , and KZnF 3 . Generally, the d - d transition of Cu 2+ in most of the reported phosphors would produce an infrared emission, since the crystal field splitting exerted on the Cu 2+ ion is usually weak.…”

Unveiling the Potential of Sunlight‐Driven Multifunctional Blue Long Persistent Luminescent Materials via Cutting‐Edge Trap Modulation Strategies

“…The increased rate provides sufficient energy for the electrons to overcome the binding forces of the traps and escape. [47] However, merely knowing the types of traps is far from sufficient for analyzing the traps in LPL materials. Accurate knowledge of trap depths is also essential because the depth of traps determines the energy barrier that released captured charge carriers need to overcome.…”

Novel dual spectral conversion via Eu2+, Cu+-coactivated core–shell-structured CaS@CaZnOS phosphors for efficient photosynthesis of plants

“…Three types of single-LCAs, i.e. , ultraviolet light to blue light (VTB), ultraviolet light to red light (VTR), green light to red light (GTR), such as Ca 1.1 Sr 0.9 SiO 4 :Ce 3+ ,Li + (VTB), 18 MZnOS:Bi 3+ /Cu + (M = Ca, Sr) (VTB), 19–23 CaS:Eu 2+ (GTR), 24–28 CaO:Eu 2+ (GTR), 29,30 SrGa 2 O 4 :Cu 2+ (VTR), 31 SrMgAl 10− y Ga y O 17 :Mn 4+ (VTR) 32 are all single-LCAs. A spectral mismatch between the sun and plants results in a waste of sunlight.…”