Yinhua Wang,Songchao Bai,Jie Sun,Hao Liang,Chao Li,Tianya Tan,Gang Yang,Jiwei Wang
Near-infrared (NIR) luminescent materials have been widely used in biomedicine, optical communication and other fields due to their unique photophysical properties. However, the development of efficient NIR luminescent materials is still a challenge. Herein, Sb 3+ , Tm 3+ co-doped Cs 2 NaYCl 6 double perovskite single crystals (SCs) have been synthesized. Benefiting from the crystal structure and rare earth lattice of rare earth-based double perovskite host, lanthanide ions can be doped effectively, and the optimal NIR photoluminescence quantum yield (PLQY) of Cs 2 NaYCl 6 :Sb 3+ , Tm 3+ SCs is up to 20.2%. The energy transfer mechanism was systematically surveyed by steady-state spectroscopy. Furthermore, a compact visible and NIR light emitting diode was fabricated by coating Cs 2 NaYCl 6 :Sb 3+ , Tm 3+ SCs on a commercial 320 nm LED chip. This light source has a promising application prospect in multifunctional lighting.
Plant cell imaging is critical for agricultural production and plant pathology study. Advanced upconversion nanoparticles (UCNPs) are being developed as fluorescent probes for imaging cells and tissues in vivo and in vitro. Unfortunately, the thick cellulosic walls as barriers together with hemicelluloses and pectin hinder the entrance of macromolecules into the epidermal plant cell. Hence, realizing satisfactory temporal and spatial resolution with UCNPs remains an arduous task. Here, bipyramidal LiErF4:1%Tm3+@LiYF4 core–shell UCNPs with a super-bright red emission upon 980 nm laser excitation are explored, where the introduction of Tm3+ ions permits alleviation of the energy loss at defective sites and a significant improvement of the upconversion output. The as-obtained bipyramidal UCNPs could readily puncture plant cell walls and further penetrate into cell membranes, facilitating improved tissue imaging of cellular internalization, as demonstrated with the luminescence images obtained by multiphoton laser-scanning microscopy. Hence our work opens up a new avenue for exploring effective upconversion nanoparticles for achieving high resolution imaging of plant tissues.
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