摘要：
In the recent years, Mn4+-doped phosphors for indoor plant cultivation have received extensive concern owing to the far-red emission that can match well with the absorption spectra of plant pigments. Whereas, many Mn4+-doped phosphors still face some challenges such as poor light efficiency and low thermal stability. It is an effective way to resolve these problems via cation vacancies engineering. Herein, the Ca14-xAl10Zn6-yO35: Mn4+ phosphors are successfully synthesized by combustion method. The luminescence intensity of Ca14-xAl10Zn6-yO35: Mn4+ phosphor is enhanced through engineering Ca2+ and Zn2+ vacancies according to the charge compensation mechanism. The optimal content of each Ca2+ and Zn2+ vacancy is equal to be 0.3. Furthermore, the defect formation is accompanied with lattice distortion, which plays a vital role in driving the excited phonon traps to reduce the energy loss by non-radiation transitions. Therefore, the thermal stability of Ca14-xAl10Zn6-yO35: Mn4+ phosphor is also improved via engineering cation vacancies. In addition, the Ca14-xAl10Zn6-yO35: Mn4+ phosphors can be effectively excited by blue light and it exhibits far-red emission due to the Mn4+ spin-forbidden E-2 -> (4)A(2) transition. The results suggest that the Ca14-xAl10Zn6-yO35: Mn4+ phosphors can have a tremendous potential in indoor plant cultivation.
摘要：
Blue-violet light can not only enhance the total content of biomass and glucoside but also enrich the taste of the fruit. Thus, it is meaningful to study the blue-violet luminescent materials for plant cultivation. In this study, titanium (IV) -activated CaYAlO4 (CYAO) phosphors were synthesized by conventional high-temperature solid-state reaction. X-ray powder diffraction was employed to analyze the crystal-structure of CYAO. It is found that the doped Ti4+ ions do not change obviously the crystal structure of phosphors. Upon 246 nm excitation, CaYAl1-xO4:xTi(4+) phosphors exhibit broad blue-violet emission band peaking at 395 nm, which can be attributed to the charge transfer of Ti4+-O2-. Moreover, this phosphor exhibits strong thermal stability. The luminescence emission intensity at 150 degrees C maintained about 91 mol% of its initial value at room temperature. Additionally, the electron transition process and concentration quenching mechanism of CaYAl1-xO4:xTi(4+)are discussed in detail. The excellent luminescent properties indicate that CaYAl1-xO4:xTi(4+) phosphor may have promising application in indoor plant cultivation. Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.
摘要：
In this paper, a series of novel orange-red emission phosphors Sr8ZnY(PO4)(7):Sm3+ (SZYP:Sm3+) were synthesized by high-temperature solid-state reaction. The photoluminescence and concentration-dependent properties of this phosphor were investigated carefully through diffuse reflection spectra, excitation and emission spectra, Commission Internationale de l'Eclairage (CIE) chromaticity coordinate and decay times. SZYP:Sm3+ could be efficiently excited by n-UV and blue lights which center at 318, 345, 363, 376, 401, 410, 440 and 475 nm, respectively. The characteristic orange-red emission peaking at 563, 601 and 647 nm had been detected, which should be attributed to the characteristic f-f forbidden transition of Sm3+. The internal quantum efficiency (IQE) of ideal phosphor of SZYP:0.09Sm(3+) reached as high as 47%. In addition, The concentration quenching mechanism and thermal stability of SZYP:Sm3+ were further investigated. It was found SZYP:Sm3+ can maintain 93% of initial emission intensity at 150 degrees C and the corresponding activation energy was calculated to be 0.26 eV based on Arrhenius formula. The emission intensity of 1.0Mg(2+) and 0.02Al(3+) incorporated SZYP:0.09Sm(3+) reached up to 134% and 117% of the initial value, respectively. Moreover, (light-emitting diodes) LED devices were fabricated by employing the optimized samples as orange-red component with 365 nm n-UV chips. The desired emission in plant absorption region and extremely high thermal stability imply that SZYP:Sm3+ is suitable for the application in plant growth LED lighting. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
摘要：
In this paper, we introduced a bluish violet emitting phosphor Ca3Al4ZnO10:Ti (IV) (CAZO:Ti⁴⁺) synthesized by high‐temperature solid‐state reaction. Upon 265 nm excitation, a broad emission band spanned from 300 nm to 500 nm and centered at 370 nm was observed. In addition, the effects of flux and charge compensation to photoluminescence properties of CAZO:Ti⁴⁺ were systematically investigated. The results show that 103% improvement of emission intensity was achieved when 1% H3BO3 flux was introduced and 32.8% enhancement of it for 2% Ca²⁺ vacancies doped as charge compensator. Moreover, the lifetimes, band gap energy, concentration quenching mechanism as well as electron transition process of CAZO:Ti⁴⁺ were discussed. Due to the efficient broad bluish violet emitting, this phosphor may find a potential application in mercury vapor‐excited fluorescent lamp for plant growth. This article is protected by copyright. All rights reserved.
摘要：
The enhancement of surface functional groups of biochar is essential to improving the biochar contaminant adsorption. Current pyrolysis methods that are accompanied by activation are energy consuming and costly. Herein, a novel wet-pyrolysis system that was carried out in open air, with simultaneous conversion and modification to produce an effective biochar adsorbent, is described. Within this system, the surface of the biochar was oxidized partially to produce sufficient functional groups at the surface, whereas carbonization of thebiomass (miscanthus sacchariflora) occurs under an acidic catalyst. The characteristic results confirmed the attachment of abundant surface functional groups, including hydroxyl and carboxyl groups, which increased in content with the ongoing reaction time. Neutralization with sodium carbonate removed the hydrogen bonds and enhanced the adsorption properties. The biochar that was obtained by using this technique exhibited an excellent cadmium adsorption capacity of 197 mg.g(-1) and a high removal efficiency of 99%. Analysis of the Cd-loaded biochar indicated that adsorption occurred via ion exchange, and formed cadmium complexes. It could be concluded that this novel wet-pyrolysis system is a promising approach to produce biochar efficiently and cost-effectively for heavy-metal remediation. (C) 2019 Elsevier Ltd. All rights reserved.
作者机构：
[Zhuang, Shuxin; Peng, Zhengyu; Lu, Mi; Zhou, Litao; Lin, Daqin; Zhuang, SX] Xiamen Univ Technol, Sch Mat Sci & Engn, Key Lab Funct Mat & Applicat Fujian Prov, Xiamen 361024, Peoples R China.;[Zhou, Nan] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Wu, Qihui] Quanzhou Normal Univ, Sch Chem Engn & Mat Sci, Dept Chem Mat, Quanzhou 362000, Peoples R China.
通讯机构：
[Zhuang, SX; Lu, M] X;Xiamen Univ Technol, Sch Mat Sci & Engn, Key Lab Funct Mat & Applicat Fujian Prov, Xiamen 361024, Peoples R China.
关键词：
Dye-sensitized solar cells;Hydrothermal method;Cu modification;Zinc oxide
摘要：
The Cu-modified ZnO nanoflowers as photoanode material for dye sensitized solar cells are synthesized via a cetylmethylammonium bromide-assisted hydrothermal method. The main phase of the synthesized samples well matches the wurtzite type phase of ZnO. And the pure phase of Cu begins to appear and strengthen when the modified-Cu content excesses 1 wt%, indicating that Cu element not only dope into the lattice of ZnO but also cover on its surfaces. It is found that the morphologies of the ZnO samples can be tuned by the change of the modified-Cu content, from irregular nanoplates to cross-linked multi-leveled porous nanoflowers with a various Cu concentration of 0.5 wt%, 1 wt%, 1.5 wt% and 2 wt%, which further facilitate the dye adsorption and light-scattering. The photocurrent-voltage characteristics and electrochemical impedance spectroscopy are conducted to estimate the electrochemical properties of these solar cells with different Cu modification contents. Compared to the dye-sensitized solar cells with pure ZnO electrode, all the dye-sensitized solar cells with Cu-modified ZnO photoelectrodes present higher photovoltaic performance. The introduction of Cu into ZnO significantly enhances electron transport and retards charge recombination in the ZnO-dye interfaces, which induce the 84% improvement of short-circuit current density and 1.6 times enhancement of the power conversion efficiency for the dye-sensitized solar cells with 1.5 wt% Cu-modified ZnO photoelectrodes. (c) 2018 Elsevier Ltd. All rights reserved.
摘要：
Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review. Various fabrication methods of these oxides are introduced in detail, and their advantages and disadvantages are analyzed. Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides. As a bifunctional electrocatalyst, perovskite-type oxides are widely used in rechargeable metal-air batteries. The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized. This work is concentrated on the structural stability, the phase compositions, and catalytic performance of perovskite-type oxides in oxygen/air electrodes. The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.
