Yining Wang,Mengmeng Shang,Yixin Sun,Minliang Deng,Xiaole Xing,Peipei Dang,Jun Lin
With the increasing demand for the application of near-infrared (NIR) spectroscopy in security, agriculture, medical and other fields, people have been seeking efficient and intelligent NIR light sources. Herein, Cr3+ doped Ca3Sc2Ge3O12 (CSGG) broadband NIR phosphors are successfully synthesized. Under excitation of 480 nm, the emission peak of CSGG:Cr3+ is located at 785 nm, and the full width at half maximum (FWHM) is 106 nm. Low photoluminescence spectra (7 K and 77 K) support the broadband NIR emission coming from two Cr3+ luminescence centers occupying ScO6 and CaO8 sites, respectively. CSGG:Cr3+ exhibits excellent thermal stability (97% at 100 °C) and low internal quantum efficiency (IQE = 22%). The introduction of Ce3+ leads to the enhancement of IQE from 22% to 61% due to the following two reasons: the energy transfer from Ce3+ to Cr3+ and the lattice distortion which improves the parity forbidden transition of Cr3+. The mechanism of excellent luminescence thermal stability is revealed from the following perspectives: thermal activation energy, the Huang–Rhys factor and the thermal ionization effect. Benefiting from the excellent performance of CSGG:Cr3+,Ce3+ NIR phosphors, the combination with blue light chips demonstrates their potential applications in night vision security, biological imaging, and nondestructive testing.
Yang Kaidong,Yang Yating,Sun Dongquan,Li Shihua,Song Xiaorong,Yang Huanghao
X-ray nanoscintillator-based photoresponsive therapy is emerging as a promising strategy to treat in vivo tumors, necessitating the development of nanoscintillators with X-ray-excited luminescence in the ultraviolet region (UV-XEL) for the photoactivation of therapeutic precursors. However, it remains a challenge to achieve high-efficiency X-ray-activated tumor therapy due to the limited UV-XEL efficacy. Herein, we developed novel Gd 3+ /Ce 3+ -codoped LiLuF 4 nanoscintillators with strong UV-XEL for in vivo tumor therapy. Significantly, through optimization of host materials, dopants, and energy transfer process, the developed nanoscintillators enabled effective enhancement of UV-XEL (up to 18-fold) as compared with the traditional Ce 3+ -doped counterparts. As a proof-of-concept study to evaluate the in vivo therapeutic applications of the nanoscintillators, we integrated them with nitric oxide (NO) precursors for controllably generating NO upon the X-ray exposure, achieving superior in vivo antitumor effect upon X-ray-induced synergetic NO therapy and radiotherapy. Moreover, X-ray-activated NO therapy can inhibit tumor metastasis into liver to suppress tumor regrowth and prolong mice survival. This work might motivate future development of X-ray nanoscintillators for treating diseases in deep tissue.
In this work, a near-infrared (NIR) phosphor Ca0.8Sr0.2O:Eu2+ was prepared via a solid-state method, and its luminescence properties were improved by co-doping with Ce3+ ions. The decay curves of Ca0.8Sr0.2O:Ce3+, Eu2+ confirmed that there was an obvious energy transfer from Ce3+ to Eu2+, which enhanced the quantum efficiency of Ca0.8Sr0.2O:Eu2+. The thermal stability can also be enhanced by introducing Ce, which reduces the probability of non-radiative transitions at elevated temperatures, thereby minimizing electron loss. An NIR light emitting diode (LED) was fabricated by combining a blue LED chip with Ca0.8Sr0.2O:Ce3+, Eu2+, which was applied for the concentration detection of ethanol solutions.
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