Tunable luminescence and efficient energy transfer investigation of a borosilicate phosphor KBSi2O6: Bi3+, Eu3+ with hypersensitive thermal quenching.

Energy transfer between Bi3+ and Eu3+ has undergone substantial research but Bi3+ and Eu3+ co-doped luminescent materials with high energy transfer efficiency for temperature sensing are rarely investigated until now. Herein, Eu3+ and Bi3+ co-doped KBSi2O6 phosphors were successfully synthesized by solid-state reaction method. The phase purity structure as well as the element distribution were carefully investigated through X-ray diffraction structural refinement and energy dispersive spectrometer analysis. The characteristic luminescence property and luminescence kinetics of KBSi2O6: Bi3+, Eu3+ were investigated. By the large spectra overlap between the emission spectrum of Bi3+ and excitation spectrum of Eu3+, the energy transfer from Bi3+ to Eu3+ can be inferred. The corresponding decrease of the emission intensity and decay time of Bi3+ in KBSi2O6: Bi3+, Eu3+ provided direct evidence for the effective energy transfer from Bi3+ to Eu3+. The interaction and energy transfer mechanism between Bi3+ and Eu3+ ions were also studied. By increasing the Eu3+ concentration in KBSi2O6: Bi3+, Eu3+, the color-tunable emission from blue to red can be realized. KBSi2O6: Bi3+, Eu3+ shows hypersensitive thermal quenching behavior and the maximum absolute sensitivity (Sa) and relative sensitivity (Sr) are determined to be 1.87 %K-1 and 2.895 %K-1, respectively. All of the above results imply that KBSi2O6: Bi3+, Eu3+ phosphor can be a color-tunable phosphor for optical temperature sensing.

Controllable luminescence and efficient energy transfer investigation of a novel white light emission phosphor Ca19Na2Mg(PO4)14: Dy3+, Tm3+ with high thermal stability.

White light emission phosphors are widely researched for application in lighting and display fields. However, the poor thermal stability is a real problem for the known single-phased white phosphors, which limits their further application. In this paper, Ca19Na2Mg(PO4)14: xDy3+, yTm3+ (CNMP, 0 ≤ x ≤ 0.06, y = 0, 0.01) phosphors with adjustable emission and good thermal stability are synthesized. The X-ray diffraction and X-ray energy dispersive spectrometer measurement distinctly confirm the successful synthesis of CNMP: xDy3+, yTm3+ (CNMP, 0 ≤ x ≤ 0.06, y = 0, 0.01). The photoluminescence results reveal that CNMP: Dy3+ shows characteristic excitation peaks in the range of 350-450 nm, and mainly exhibits strong yellow emission around 575 nm ascribed to the 4F9/2-6H13/2 transitions of Dy3+. To compensate the deficiency of blue light emission of CNMP: Dy3+, the trivalent Tm3+ ion is co-doped owing to its characteristic blue emission at 450 nm due to its 1D2-3F4 transitions. Therefore, the emission of CNMP: Dy3+, Tm3+ can be tuned from blue light region with CIE coordinates of (0.1649, 0.0387) to white light region with CIE coordinates of (0.3001, 0.3003) and finally move to yellow light region with CIE coordinates of (0.3732, 0.4493) through adjusting the doping ratio of Dy3+/Tm3+. The energy transfer efficiency and the energy transfer mechanism from Tm3+ to Dy3+ are further investigated. Moreover, CNMP: Dy3+, Tm3+ exhibites a high thermal stability and the emission intensity still keeps 84% of the initial intensity of Dy3+ at 230 °C. These outstanding properties show that Ca19Na2Mg(PO4)14: Dy3+, Tm3+ have great advantages and potentiality for applying in solid state lighting.

The complete mitochondrial genome of Bombax ceiba.

Bombax ceiba is a beautiful and deciduous tree with important economic and ecological values. Here, we sequenced the intact mitochondrial genome (mitogenome) of B. ceiba on the PacBio sequencing platform (Pacific Biosciences, Menlo Park, CA). The mitogenome is 594,390 bp and is comprised of 35 protein-coding genes, two rRNA genes, and 25 tRNA genes. The phylogeny analysis suggested that B. ceiba was closely clustered with the genus Gossypium.

Complete chloroplast genome sequence of the red silk cotton tree (Bombax ceiba).

Bombax ceiba L. is a beautiful and deciduous tree with great ecological and economic importance. The third generation sequencing of chloroplast genome of B. ceiba was conducted on the PacBio sequencing platform (Pacific Biosciences). The complete chloroplast genome was 158,997 bp, which contains a large single-copy (LSC) region (89,021 bp), a small single-copy (SSC) region (21,110 bp), and two inverted repeats (IRs) (24,433 bp). In total, 116 genes were annotated, including 81 protein-coding genes, eight rRNA genes, and 27 tRNA genes. The phylogenetic tree showed that B. ceiba was closely clustered with one clade of Malvaceae.

Genetic diversity and phylogenetic relationships of seven Amorphophallus species in southwestern China revealed by chloroplast DNA sequences.

Plants species in the genus Amorphophallus are of great economic importance, as they are the only plants known to produce glucomannan. Although southwestern China has been recognized as one of the origin centres of Amorphophallus, only a few studies assessing its genetic diversity have been reported. To aid in the utilization and conservation of Amorphophallus species, we evaluated the genetic diversity and phylogenetic relationships among seven edible Amorphophallus species using three chloroplast DNA regions (rbcL, trnL and trnK-matK). The results showed that the genetic diversity at the population level was relatively low, with over half of the populations harbouring only one haplotype. The widely scattered species, A. konjac, had the largest genetic diversity, while the narrow endemic species, A. yuloensis, possessed only one haplotype. Phylogeny analysis identified three well-supported major lineages. Our study suggested that habitat fragmentation might be a driver of the genetic variation patterns within and between populations of Amorphophallus. A conservation strategy consisting of in situ conservation and germplasm collection is recommended.