Macroscopic Models for the Radiative Relaxation Lifetime of Luminescent Centers Embedded in Surrounding Media

Two macroscopic models for the dependence of the spontaneous emission rate of luminescent ions or nanoparticles embedded in dielectric media of various optical refractive indexes are presented. The available experimental results on the spontaneous emission rate (lifetime) are examined using the two models. A simple criterion for how to choose the proper model for a given system is summarized.     

Review on the Role of Polymers in Luminescent Solar Concentrators

The use of luminescent solar concentrators (LSCs) offers an alternative approach to integrating photovoltaic technologies into the built environment. The research on LSCs has bloomed in the past decade in terms of searching for novel device architectures, developing new luminescent species, and employing unique host materials. This article will provide a concise review on LSCs and focus on the polymer host materials used in LSCs. Finally, we provide a brief outlook on the future development of this research area, particularly on the polymers used as host materials and luminescent species for LSCs. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 201–215     

Dye-integrated cholesteric photonic luminescent solar concentrator

We have developed organic dye-integrated thin-film liquid crystalline photonic luminescent solar concentrators (LSCs), where the chirality of the liquid crystal (LC) results in the formation of a one-dimensional photonic cavity. By varying the different LSC parameters, including dye concentration, spectral position of the photonic band-gap and the LC phase, and by using spectroscopic and electrical characterisation, we have systematically studied the effects of self-absorption, incident absorption and confinement of down-converted emission on optical efficiency. Our results demonstrate that the efficiency of our LSCs is significantly enhanced in the LC phase when the photonic band-gap is at long wavelengths (>600 nm), overcoming associated low incident absorption and higher self-absorption. We reach the significant conclusion that focusing on improving the confinement of dye-emitted photons, rather than on increasing incident absorption, is a more promising route to enhancing thin-film LC-based LSC performance.     

Increasing Luminescent Yield By Pulsed Laser Excitation

Luminescence of dyed systems induced by laser irradiation has been studied. Significant increases in luminescence yield have been observed as the laser pulse width decreases. For nanosecond pulses, the weaker emitting systems had the highest percentage of increase. For short pulses, metastable species are not expected to build up and quench the emission.     

Tailor-Made Amino Acids in Pharmaceutical Industry: Synthetic Approaches to Aza-Tryptophan Derivatives

Over the recent years there has been a noticeable upsurge of interest in aza-analogs of tryptophan which are isosteric to the latter and found numerous applications in medicinal, bioorganic chemistry, and peptide research. In the present review article, five aza-tryptophan derivatives are profiled, including aza-substitution in the positions 2, on the five-membered ring, as well as in positions 4, 5, 6, and 7 on the six-membered ring. A detailed and comprehensive literature overview of the synthetic methods for the preparation of these aza-tryptophans is presented and general facets of the biological properties and most promising applications are discussed.     

SrB_4O_7∶Eu磷光粉的制备及其发光性能

采用高温固相法合成了SrB4O7∶Eu荧光粉,并研究了不同原料、掺杂浓度、煅烧温度等因素对其发光性能的影响。发射光谱测试结果表明:SrB4O7∶Eu荧光粉的最佳Eu掺杂浓度为2%左右,进一步增大掺杂浓度会导致浓度猝灭。煅烧温度对基质组成影响较大,随着温度的升高,基质中BO4四面体所占比例增大,有利于Eu3+离子的还原。以水合硼酸锶为原料制得样品的发光强度高于以SrCO3和H3BO3为原料制得样品的发光强度。     

Playing with PtII and ZnII Coordination to Obtain Luminescent Metallomesogens

Blue–green luminescent terpyridine-containing Pt^II and Zn^II complexes are reported. Equipped with lipophilic gallate units, which act as monodentate ancillary coordinating ligands and/or as anions, they display low-temperature mesomorphic properties (lamello-columnar and hexagonal mesophases for Pt^II and Zn^II complexes, respectively). The mesomorphic properties were investigated by polarised optical microscopy, differential scanning calorimetry, thermogravimetric analysis and X-ray scattering of bulk materials and oriented thin films. The model of self-assembly into the lamello-columnar phase of the Pt^II complex has been described in detail. The optical properties of the complexes were investigated in the liquid and condensed liquid crystalline states, highlighting the delicate balance between the role of the metal in determining the type of excited state responsible for the emission, and the role of the ancillary ligand in driving intermolecular interactions for proper mesophase formation.     

A family of functional Ln‐organic framework constructed by iodine‐substituted aromatic polycarboxylic acid for turn‐off sensing of UO22+

With the rapid development of nuclear energy, one of the main constraints restricting the development of nuclear energy is the long‐term safe disposal of strong uranium waste. Here it is a great significance that we use four new synthetic Ln (III)‐based coordination polymers to test the uranium solution. In this study, four three‐dimensional coordination polymers 1 – 4 (CPs‐( 1–4 ); Ln = Eu, Gd, Sm, Nd) were successfully synthesized through 1:1 complexation of Ln (NO₃)₃·6H₂O with poly‐carboxylic acid ligand H₃TIBTC (2,4,6‐Triiodo‐1,3,5‐benzene tricarboxylic acid) which contains substituents of the carboxylic acid group and halogen atom, respectively. Based on the ligand being excellent fluorescent properties in the solution, it prompted us to further study the fluorescence properties of the coordination polymers. Experimental results show that the coordination polymers are favorable materials for the simultaneous selective detection uranium solution from water, being potentially useful in monitoring water quality and treating uranium‐wastewater.     

Bulk Mn2+ Doped 1D Hybrid Lead Halide Perovskite with Highly Efficient,Tunable and Stable Broadband Light Emissions

Mn²⁺ doped colloidal three-dimensional (3D) lead halide perovskite nanocrystal (PNC) has attracted intensive research attention; however, the low exciton binding energy and fatal optical instability of 3D PNC seriously hinder the optoelectronic application. Therefore, it remains significant to explore new stable host perovskite with strongly bound exciton to realize more desirable luminescent property. In this work, we utilized bulk one-dimensional (1D) hybrid perovskite of [AEP]PbBr₅ ⋅ H₂O (AEP=N-aminoethylpiperazine) as structural platform to rationally optimize the luminescent property by a controllable Mn²⁺ doping strategy. Significantly, the series of Mn²⁺-doped 1D [AEP]PbBr₅ ⋅ H₂O show enhanced energy transfer efficiency from the strongly bound excitons of host material to 3d electrons of Mn²⁺ ions, resulting in tunable broadband light emissions from weak yellow to strong red spectral range with highest photoluminescence quantum yield up to 28.41 %. More importantly, these Mn²⁺-doped 1D perovskites display ultrahigh structural and optical stabilities in humid atmosphere, water and high temperature exceeding the conventional 3D PNC. Combined highly efficient, tunable and stable broadband light emissions enable Mn²⁺-doped 1D perovskite as excellent down-converting phosphor showcasing the potential application in white light emitting diode. This work not only provides a profound understanding of low-dimensional perovskites but also opens a new way to rationally design high-performance broadband light emitting perovskites for solid-state lighting and displaying devices.     

A New 1D Zinc Coordination Polymer Constructed by 1-Naphthylacetate and 4,4＇-bpy：Synthesis,Structure and Luminescent Property

One new zinc coordination polymer,[Zn(NAA)2(4,4'-bpy)]n(1,HNAA = 1-naphthaleneacetic acid,4,4'-bpy = 4,4'-bipyridine),has been synthesized under hydrothermal conditions and characterized by elemental analysis,IR spectroscopy,thermogravimetric analysis(TGA),and single-crystal X-ray diffraction.Coordination polymer 1 is of monoclinic system,space group Cc with a = 9.8720(6),b = 16.7397(9),c = 17.0371(12) ,β = 104.8080(10)°,V = 2721.9(3)3,C34H26N2O4Zn,Z = 4,Mr = 591.94,Dc = 1.444 g/cm3,μ(MoKα) = 0.946 mm-1,F(000) = 1224,the final R = 0.0282 and wR = 0.0720 for 3300 observed reflections with I > 2σ(I).1 exhibits an interesting one-dimensional chain structure.Furthermore,the luminescent property of 1 has also been investigated.