Lanthanide-based luminescent hybrid materials.

Uniform, spherical-shaped TiO2:Eu nanoparticles with different doping concentrations have been synthesized through controlled hydrolysis of titanium tetrabutoxide under appropriate pH and temperature in the presence of EuCl3·6H2O. Through air annealing at 500°C for 2 h, the amorphous, as-grown nanoparticles could be converted to a pure anatase phase. The morphology, structural, and optical properties of the annealed nanostructures were studied using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy [EDS], and UV-Visible diffuse reflectance spectroscopy techniques. Optoelectronic behaviors of the nanostructures were studied using micro-Raman and photoluminescence [PL] spectroscopies at room temperature. EDS results confirmed a systematic increase of Eu content in the as-prepared samples with the increase of nominal europium content in the reaction solution. With the increasing dopant concentration, crystallinity and crystallite size of the titania particles decreased gradually. Incorporation of europium in the titania particles induced a structural deformation and a blueshift of their absorption edge. While the room-temperature PL emission of the as-grown samples is dominated by the 5D0 - 7Fj transition of Eu+3 ions, the emission intensity reduced drastically after thermal annealing due to outwards segregation of dopant ions.

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Effects of crystallization and dopant concentration on the emission behavior of TiO2:Eu nanophosphors

Sasidharan Swarnalatha Lucky,†,§ Khee Chee Soo,‡ and Yong Zhang*,†,§,∥ †NUS Graduate School for Integrative Sciences & Engineering (NGS), National University of Singapore, Singapore, Singapore 117456 ‡Division of Medical Sciences, National Cancer Centre Singapore, Singapore, Singapore 169610 Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore, Singapore 117576 College of Chemistry and Life Sciences, Zhejiang Normal University, Zhejiang, P. R. China 321004

Nanoparticles in photodynamic therapy.

Yuming Yang,†,§ Qiang Zhao,‡,§ Wei Feng,† and Fuyou Li*,† †Department of Chemistry and State Key Laboratory of Molecular Engineering of Polymers and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, P. R. China ‡Key Laboratory for Organic Electronics and Information Displays (KLOEID) and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, Nanjing 210046, P. R. China.

Luminescent chemodosimeters for bioimaging.

Applications in Theranostics Guanying Chen,*,†,‡ Hailong Qiu,†,‡ Paras N. Prasad,*,‡,§ and Xiaoyuan Chen* †School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China ‡Department of Chemistry and the Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, New York 14260, United States Department of Chemistry, Korea University, Seoul 136-701, Korea Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892-2281, United States

Upconversion Nanoparticles: Design, Nanochemistry, and Applications in Theranostics

Karbowiak et al. recently commented on our Communication “Breakdown of Crystallographic Site Symmetry in Lanthanide-Doped NaYF4 Crystals”. [1] They attempted to criticize the crystal-field (CF) analysis of Eu in disordered NaYF4 based on their surmise. Unfortunately, there are numerous misunderstandings in their correspondence. In this reply, we respond to their comment and clarify our interpretations of the issues they raised. Regarding the adoption of the CF parameters (CFPs) of Eu in Gd2O3 as the starting values in the fit, it is true that the coordination environments of Gd2O3 and NaYF4 host are somewhat different. However, it should be pointed out that both aand b-NaYF4 are disordered crystals, where the site symmetry of Y isOh and C3h, respectively. [3] Once Eu ions are doped into such disordered crystals to substitute for Y, the symmetry of spectroscopic sites of Eu may differ drastically from that of crystallographic sites of Y, which is due to the mismatch of ionic radius between Eu and Y. The local site symmetry of Eu in NaYF4 can be revealed by the high-resolution emission spectra (Figure 1), selective excitation spectra, and photoluminescence (PL) decays at low temperature (Supporting Information, Figure S1). Note that our emission pattern of b-NaYF4:Eu 3+ is consistent with that reported by other groups. For instance, the line positions and splittings reported by Jia et al. are nearly identical to our results (Figure 1). In the PL pattern, the most crucial fingerprint to corroborate the low site symmetry in NaYF4:Eu 3+ crystals is the appearance of the D0!F0 peak. Furthermore, three and five CF transition lines of D0 to F1 and F2 were observed, which demonstrated the highest site symmetry of Eu in b-NaYF4, distorted from C3h, should be Cs. Such breakdown of crystallographic site symmetry in Eu-doped NaYF4 crystals was not only corroborated by these PL spectra, but also confirmed by the CF level fitting. To the best of our knowledge, until now no data on the CFPs of NaYF4 or other disordered crystals with similar structure and local site symmetry are available. The choice of the set of CFPs values of Gd2O3 as the starting ones in the fit is technically feasible based on the following considerations. First, as mentioned in Ref. [1], the highest spectroscopic site symmetries of Eu are found to descend from crystallographic Oh to Cs (or C2) in a-NaYF4, and from crystallographic C3h to Cs in b-NaYF4, respectively. Similar to the wellestablished CFP fitting strategy in this field, to rationally reduce the number of freely varied CFPs in the fit, we performed the energy level fitting by reasonably assuming the highest site symmetry of Cs for both aand b-NaYF4 in view of the same set of allowed CFPs for the site symmetry of Cs or C2. [7] Second, by using the CFPs of Gd2O3:Eu 3+ as starting values, the energy-level fitting yielded a relatively small root-mean-square deviations for aand b-NaYF4, namely, 13.5 and 13.8 cm 1 (with energy shifts in a range of 0–30 cm 1 for most of the levels), respectively, an important indicator for the goodness of the fit. Note that total 48 CF levels of Eu in a-NaYF4, instead of 41 levels as they criticized in their comment, were included in our fit. Figure 1. 10 K PL emission spectra of b-NaYF4:Eu 3+ reported in Ref. [5a] (upper) and our original work (lower), respectively. The CF transition line from D0 to F0 is marked by an asterisk.

Reply to Comment on “Breakdown of Crystallographic Site Symmetry in Lanthanide‐Doped NaYF4 Crystals”

Highly efficient NIR-II luminescent I-III-VI semiconductor nanoprobes based on AgInTe2:Zn/ZnS nanocrystals.

Modulator-directed assembly of hybrid composites based on metal-organic frameworks and upconversion nanoparticles

Development of new mechanochromic luminescent (MCL) materials from aggregation-induced emission luminogens (AIEgens) has attracted wide attention due to their potential application in multiple areas. However, rational design and crafting of new MCL materials from the simple AIEgens skeleton is still a big challenge because of the undesirable concentration quenching effect. In this study, we have constructed a new class of MCL materials by adding one phenyl as a new rotator and incorporating one pair of electron donor (D) and acceptor (A) into the system of rofecoxib skeleton. This strategy endowed the compounds (Y1-Y8) with tunable emission behavior and some of them with the AIE effect and reversible MCL behavior. These properties may be caused by the highly twisted conformation and loosely molecular packing modes, which were elucidated clearly by analyzing the data of single-crystal X-ray diffraction, powder X-ray diffraction, and differential scanning calorimetry. Further investigation revealed that Y7 displayed acidochromic property due to the protonation of the nitrogen atom. Moreover, Y7, as a typical compound, showed its potential applications in the area of anticounterfeiting, pH sensor, and LD-specific bioimaging.

New Rofecoxib-Based Mechanochromic Luminescent Materials and Investigations on Their Aggregation-Induced Emission, Acidochromism, and LD-Specific Bioimaging.

-butyl)titanate dissolved in absolute ethanol (40 mL), the mixture wasstirred vigorously with a magnetic stirrer at room temperature.After continuous stirring for 3 h, the obtained cloudy mixturewas transferred to 50-mL Teﬂon-lined autoclaves and thensubjected to solvothermal treatment for5hat120°C. Coolingto room temperature led to the white precipitates that werecollected by centrifugation and washed with absolute ethanolfor several times. The precipitates were dried at 60 °C for 12 hand then heat treated at 500 °Cfor2htoyield the ﬁnal products.Hereafter, without special explanation, the samples TiO

Xueyuan Chen

Papers

Reply to Comment on “Breakdown of Crystallographic Site Symmetry in Lanthanide‐Doped NaYF4 Crystals”

Highly efficient NIR-II luminescent I-III-VI semiconductor nanoprobes based on AgInTe2:Zn/ZnS nanocrystals.

Modulator-directed assembly of hybrid composites based on metal-organic frameworks and upconversion nanoparticles

New Rofecoxib-Based Mechanochromic Luminescent Materials and Investigations on Their Aggregation-Induced Emission, Acidochromism, and LD-Specific Bioimaging.

Ions Incorporated in Anatase Titania Nanocrystals