Co-reporter:Yinjian Zheng, Gancheng Xie, Xuejie Zhang, Zhijie Chen, Yijin Cai, Wen Yu, Hechou Liu, Junyang Shan, Ruimin Li, Yingliang Liu, and Bingfu Lei
ACS Omega July 2017? Volume 2(Issue 7) pp:3958-3958
Publication Date(Web):July 26, 2017
DOI:10.1021/acsomega.7b00657
Carbon dots (CDs) obtained from rapeseed pollen with a high production yield, good biocompatibility, good water solubility, low cost, and simple synthesis are systematically characterized. They can be directly added to Hoagland nutrient solution for planting hydroponically cultivated Lactuca sativa L. to explore their influence on the plants at different concentrations. By measuring lettuce indices of growth, morphology, nutrition quality, gas exchange, and content of photosynthetic pigment, amazing growth-promotion effects of CDs were discovered, and the mechanism was analyzed. Moreover, the in vivo transport route of CDs in lettuce was evaluated by macroscopic and microscopic observations under UV light excitation. The results demonstrate that pollen-derived CDs can be potentially used as a miraculous fertilizer for agricultural applications and as a great in vivo plant bioimaging probe.Topics: Biological imaging; Biological transport; Carbohydrates; Cell and Molecular biology; Dyes and Chromophores; Electromagnetic wave; Nanofabrication; Proteins; Quantum dots;
Co-reporter:Yue Zhu;Jin Wang;Mingyi Zhao;Chonghui Chen;Lingling Zheng;Yingliang Liu;Haoran Zhang
RSC Advances (2011-Present) 2017 vol. 7(Issue 14) pp:8230-8235
Publication Date(Web):2017/01/23
DOI:10.1039/C6RA28209A
Spectral tuning and thermal stability are important for the optimization and modification of phosphor materials. Herein we report a solid solution of Sr2Si1−xAlxO4−2xNx:Eu phosphors in which cation–anion substitution (Al3+–N3− replacing Si4+–O2−) leads to the co-existence of Eu2+ and Eu3+ activators even under a reducing atmosphere. X-ray diffraction, FT-IR, photoluminescence analysis, UV-vis absorption and fluorescence lifetime studies indicated that the structure reconstruction contributes to tunable emission colors and better thermal quenching behavior, which are valuable for pc-WLED applications.
Co-reporter:Yonghao Chen;Jiangling He;Chaofan Hu;Haoran Zhang;Yingliang Liu
Journal of Materials Chemistry C 2017 vol. 5(Issue 25) pp:6243-6250
Publication Date(Web):2017/06/29
DOI:10.1039/C7TC01615H
Phosphorescence is difficult to be observed from carbon dot powder due to the deliquescence and self-quenching in the aggregation state. In this study, aggregation-induced room temperature phosphorescence (RTP) is first reported in self-quenching-resistant nitrogen-doped carbon dot powder, which is suggested to take advantage of the moisture-resistance, rigidization and oxygen-barrier induced by PVA-chains. Furthermore, the optical mechanism of RTP as well as fluorescence is investigated through the abnormal excitation-responsive phenomena, and the potential application in temperature sensing is also preliminarily evaluated. This study may benefit in developing phosphorescence from undesirable aggregation through structure design and exploiting emerging applications for carbon dots.
Co-reporter:Li Wang;Haoran Zhang;Xiaohua Zhou;Yingliang Liu
RSC Advances (2011-Present) 2017 vol. 7(Issue 27) pp:16662-16667
Publication Date(Web):2017/03/14
DOI:10.1039/C7RA00227K
Light-emitting diodes (LEDs) are widely used for artificial lighting in plant factories and have been applied for disease prevention and for accelerating plant growth. In this study, a unique dual-emitting core–shell CDs/CaAlSiN3:Eu2+-silica powder was prepared by a one-pot sol–gel method. LED devices with multi-wavelength emission (623 nm red light and 465 nm blue light) were fabricated using the as-prepared dual-emitting core–shell CDs/CaAlSiN3:Eu2+-silica powder, and the electrical characteristics of these LED devices were evaluated. Furthermore, it was demonstrated that these LED devices could be used for plant growth lighting in plant factories. The LEDs prepared in the present study for plant growth lighting have the advantage of being convenient, low-cost, non-toxic, and stable compared with traditional LED devices for plant growth lighting.
Co-reporter:Li Wang;Haoran Zhang;Xiaohua Zhou;Yingliang Liu
RSC Advances (2011-Present) 2017 vol. 7(Issue 27) pp:16662-16667
Publication Date(Web):2017/03/14
DOI:10.1039/C7RA00227K
Light-emitting diodes (LEDs) are widely used for artificial lighting in plant factories and have been applied for disease prevention and for accelerating plant growth. In this study, a unique dual-emitting core–shell CDs/CaAlSiN3:Eu2+-silica powder was prepared by a one-pot sol–gel method. LED devices with multi-wavelength emission (623 nm red light and 465 nm blue light) were fabricated using the as-prepared dual-emitting core–shell CDs/CaAlSiN3:Eu2+-silica powder, and the electrical characteristics of these LED devices were evaluated. Furthermore, it was demonstrated that these LED devices could be used for plant growth lighting in plant factories. The LEDs prepared in the present study for plant growth lighting have the advantage of being convenient, low-cost, non-toxic, and stable compared with traditional LED devices for plant growth lighting.
Co-reporter:Wan Zhou;Jianle Zhuang;Wei Li;Chaofan Hu;Yingliang Liu
Journal of Materials Chemistry C 2017 vol. 5(Issue 32) pp:8014-8021
Publication Date(Web):2017/08/17
DOI:10.1039/C7TC01819C
Herein, unique S and N co-doped carbon dots (S,N-C-dots) were synthesized via a one-pot hydrothermal method. The S,N-C-dots not only possess a relatively high photoluminescence (PL) quantum yield (QY) (43%), but also present unique optical properties with dual-emission (blue and yellow) and excitation-independent characteristics. It is extremely rare for bare carbon dots (C-dots) to have dual-emission under single excitation wavelength. Herein, we achieved a series of solid-state lighting materials, such as silica-encapsulated C-dots (silica/C-dots), light conversion films (LCFs), and white-light-emitting diodes (WLEDs), using S,N-C-dots as a doping fluorophore. Moreover, we conducted some comparative experiments to prove that the unique properties of the S,N-C-dots were ascribed to the co-doping effects of S and N atoms. The yellow emission originates from the intrinsic state emission and the blue emission originates from the surface energy trap emission. This study presents a facile preparation of highly efficient dual-emissive S,N-C-dots and provides a new strategy to develop various solid-state lighting materials.
Co-reporter:Yinjian Zheng;Haoran Zhang;Wei Li;Yingliang Liu;Xuejie Zhang;Houcheng Liu
RSC Advances (2011-Present) 2017 vol. 7(Issue 53) pp:33459-33465
Publication Date(Web):2017/06/29
DOI:10.1039/C7RA04644H
Carbon dots (CDs), synthesized from biological sources, have attracted attention in bioimaging and bioscience due to their low cytotoxicity, water-soluble nature, and biocompatibility. However, there are a few reports on the absorption of elements and tracking the transporting systems in plants. Herein, we report pollen-CDs synthesized by a hydrothermal method that emit blue light under excitation of UV light, which can be used to track the absorption of nitrogen, phosphorus, and potassium, and mark the biological transport systems in Brassica parachinensis L. The pollen-CDs were transported via the vascular system of Brassica parachinensis L., confirmed by the confocal images. TEM results demonstrated that the pollen-CDs were enriched in the periplasmic space, which helps to enhance the absorption efficiency of potassium and inhibit the accumulation of nitrates in Brassica parachinensis L. The hydroponic experiment results demonstrated that Brassica parachinensis L. had the highest yield of 42.90 mg when 3.5 mg L−1 pollen-CDs were added to the nutrient solution. All the results demonstrated that the pollen-CDs have potential for application in hydroponically grown vegetables and biocompatible studies in vitro/in vivo imaging.
Co-reporter:Wei Li;Haoran Zhang;Yinjian Zheng;Shi Chen;Yingliang Liu;Jianle Zhuang;Wei-Ren Liu
Nanoscale (2009-Present) 2017 vol. 9(Issue 35) pp:12976-12983
Publication Date(Web):2017/09/14
DOI:10.1039/C7NR03217J
A new class of carbon dot (CD) grafted cellulose hybrid phosphors has been prepared in a facile and fast process. The reddish-orange emissive CDs can be effectively dispersed in cellulose matrices through hydrogen binding, and thus highly efficient orange-emissive CD-based phosphors were successfully obtained with a quantum yield of 44%. Moreover, the affinity of CDs for binding cellulose provides them the feasibility for fluorescence mapping of cellulosic plant cell walls. Several model plant tissues have been employed to investigate the pathway of CDs. Confocal analysis demonstrated that plant tissues can readily absorb CDs from aqueous solutions and bind them with cellulose-rich structures. These studies may open up new avenues for the exploration of CDs in long-wavelength emissive solid-state lighting and plant tissue imaging.
Co-reporter:Yinjian Zheng;Haiming Zhang;Haoran Zhang;Xuejie Zhang;Yingliang Liu
RSC Advances (2011-Present) 2017 vol. 7(Issue 61) pp:38498-38505
Publication Date(Web):2017/08/02
DOI:10.1039/C7RA05861F
The red emitting CaZnOS:Mn2+ long persistent phosphor was successfully prepared via a conventional high-temperature solid-state reaction method. The persistent luminescence emission of Mn2+-doped CaZnOS phosphor was investigated for the first time. Rare-earth trivalent ions were used as co-dopants to obtain a brighter red afterglow and longer persistence time. The optical properties of the as-prepared samples have been investigated systematically by employing photoluminescence spectroscopy, persistent luminescence spectroscopy, afterglow decay curves and thermoluminescence curves. In light of the experimental results of this study, a possible mechanism of persistent luminescence was illustrated and discussed in detail. These investigations provide a new and efficient long persistent phosphor.
Co-reporter:Yinjian Zheng;Haiming Zhang;Haoran Zhang;Xuejie Zhang;Yingliang Liu
RSC Advances (2011-Present) 2017 vol. 7(Issue 61) pp:38498-38505
Publication Date(Web):2017/08/02
DOI:10.1039/C7RA05861F
The red emitting CaZnOS:Mn2+ long persistent phosphor was successfully prepared via a conventional high-temperature solid-state reaction method. The persistent luminescence emission of Mn2+-doped CaZnOS phosphor was investigated for the first time. Rare-earth trivalent ions were used as co-dopants to obtain a brighter red afterglow and longer persistence time. The optical properties of the as-prepared samples have been investigated systematically by employing photoluminescence spectroscopy, persistent luminescence spectroscopy, afterglow decay curves and thermoluminescence curves. In light of the experimental results of this study, a possible mechanism of persistent luminescence was illustrated and discussed in detail. These investigations provide a new and efficient long persistent phosphor.
Co-reporter:Yonghao Chen;Mingtao Zheng;Yong Xiao;Hanwu Dong;Haoran Zhang;Jianle Zhuang;Hang Hu;Yingliang Liu
Advanced Materials 2016 Volume 28( Issue 2) pp:312-318
Publication Date(Web):
DOI:10.1002/adma.201503380
Co-reporter:Wei Li, Yinjian Zheng, Haoran Zhang, Zulang Liu, Wei Su, Shi Chen, Yingliang Liu, Jianle Zhuang, and Bingfu Lei
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 31) pp:19939
Publication Date(Web):July 18, 2016
DOI:10.1021/acsami.6b07268
Fluorescent carbon dots (CDs) have been widely studied in bioscience and bioimaging, but the effect of CDs on plants has been rarely studied. Herein, mung bean was adopted as a model plant to study the phytotoxicity, uptake, and translocation of red emissive CDs in plants. The incubation with CDs at a concentration range from 0.1 to 1.0 mg/mL induced physiological response of mung bean plant and imposed no phytotoxicity on mung bean growth. The lengths of the root and stem presented an increasing trend up to the treatment of 0.4 mg/mL. Confocal imaging showed that CDs were transferred from the roots to the stems and leaves by the vascular system through the apoplastic pathway. The uptake kinetics study was performed and demonstrated that the CDs were abundantly incubated by mung beans during both germination and growth periods. Furthermore, in vivo visualization of CDs provides potential for their successful application as delivery vehicles in plants based on the unique optical properties.Keywords: bioimaging; carbon dots; fluorescent; mung bean; phytotoxicity
Co-reporter:Wei Li;Haoran Zhang;Shi Chen;Yingliang Liu;Jianle Zhuang
Advanced Optical Materials 2016 Volume 4( Issue 3) pp:427-434
Publication Date(Web):
DOI:10.1002/adom.201500572
A series of carbon dots (CDs) grafted CaAl12O19:Mn4+ (CAO) color-tunable hybrid phosphors have been synthesized via a facile sol-gel method. Through the hydrolysis and condensation reactions of the silica precursor, CDs can be incorporated into highly flexible hybrid materials through combining with a CaAl12O19:Mn4+ phosphor within silica gel networks for the fabrication of flexible displays and multicolor luminescent materials. By tuning the mass ratio of CDs/CAO and by adjusting the excitation wavelength, the color of the luminescence can be systematically tailored from purplish-red (0.504, 0.250) to greenish-blue (0.238, 0.192). Furthermore, the temperature-dependent luminescent properties of the CDs/CAO phosphors makes them suitable as thermometers with a wide linear temperature sensing range from 80 to 300 K.
Co-reporter:Li Wang, Haoran Zhang, Xiaohua Zhou, Yingliang Liu, Bingfu Lei
Journal of Colloid and Interface Science 2016 Volume 478() pp:256-262
Publication Date(Web):15 September 2016
DOI:10.1016/j.jcis.2016.06.026
In this paper, our effort was focused on preparation and oxygen sensing of luminescence carbon dots (CDs) assembled hollow mesoporous silica microspheres (HMSMs) and mesoporous silica microspheres (MSMs). MSMs doped with CDs showed shorter response time and recovery time comparing with HMSMs doped with CDs. This feature can be attributed to ordered channel structure of mesoporous carrier which can promote the gas diffusion effectively. While HMSMs doped with CDs shows a higher oxygen quenching response and the degree of quenching reach 80.35%. The response time was determined to be about 7 s and the emission intensities of the samples were effectively reduced as the concentration of oxygen increased. These results indicate that the system we have developed can be used for oxygen detection in wide concentration range and is especially accurate for very low oxygen concentrations. The obtained CDs grafted hollow mesoporous silica microspheres (HMSMs) and mesoporous silica microspheres (MSMs) samples appears to be a promising sensing material for environmental detection application and would also find applications in catalyst, electrode, or related fields.
Co-reporter:Yaqin You, Haoran Zhang, Yingliang Liu, Bingfu Lei
Carbohydrate Polymers 2016 Volume 151() pp:245-250
Publication Date(Web):20 October 2016
DOI:10.1016/j.carbpol.2016.05.063
•It’s the first time sunlight conversion property of carbon dots is discussed.•The hydrogen bond is formed between the carbon dots and carboxymethyl cellulose.•Furthermore, the mechanical properties of the composite film are improved.•Finally, this film is expected to apply in agriculture for sunlight conversion.Transparent sunlight conversion film based on carboxymethyl cellulose (CMC) and carbon dots (CDs) has been developed for the first time through dispersion of CDs in CMC aqueous solution. Due to the hydrogen bonds interaction, CMC can effectively absorb the CDs, whose surfaces are functionalized by lots of polar groups. The results from atomic force microscopy (AFM), scanning electron microscopy (SEM) confirm that the composite film possesses a homogeneous and compact structure. Besides, the CMC matrix neither competes for absorbing excitation light nor absorbs the emissions of CDs, which reserves the inherent optical properties of the individual CDs. The composite films can efficiently convert ultraviolet light to blue light. What’s more, the film is transparent and possesses excellent mechanical properties, expected to apply in the field of agricultural planting for sunlight conversion.
Co-reporter:Haiming Zhang, Haoran Zhang, Weiren Liu, Yingliang Liu, Bingfu Lei, Jiankun Deng, Jinyuan Zhang, Siyuan Yan, Haobin Kuang, Jinda Zang
Ceramics International 2016 Volume 42(Issue 15) pp:16659-16665
Publication Date(Web):15 November 2016
DOI:10.1016/j.ceramint.2016.07.097
Abstract
In this paper, a series of Ce3+ doped Sr2MgAl22O36 (SMA) phosphors have been prepared by high temperature solid-state reaction method. The phase structure of prepared samples was checked by the powder X-ray diffraction (XRD). The morphology of the samples was inspected using a field-emission scanning electron microscope (SEM). Under different UV radiation, this phosphor exhibits different emission bands due to the Ce3+ ions located at different lattice sites. The corresponding luminescence and energy transfer mechanisms have been proposed in detail. The phosphor exhibits different concentration quenching mechanisms because the Ce3+ ions substitute two different crystallographic sites in the host. Moreover, the temperature dependent emission properties of SMA:Ce3+ were conducted from 30 °C to 200 °C, as much as 72.96% of the room-temperature emission intensity is retained at 150 °C. The SMA:Ce3+ phosphor exhibits bright blue emission with CIE coordinates (x=0.16, y=0.12) under UV excitation. The results indicate that SMA:Ce3+ phosphor has great potential applications in UV-pumped light emitting diodes.
Co-reporter:Haiming Zhang, Haoran Zhang, Jianle Zhuang, Hanwu Dong, Yue Zhu, Xiyun Ye, Yingliang Liu, Bingfu Lei
Ceramics International 2016 Volume 42(Issue 11) pp:13011-13017
Publication Date(Web):15 August 2016
DOI:10.1016/j.ceramint.2016.05.076
Abstract
H3BO3 was added during the preparation of Sr2MgAl22O36:Mn4+ phosphors by a high-temperature solid-state reaction method. The influence of H3BO3 flux on the crystal structure, particle morphology and photoluminescence properties of the Sr2MgAl22O36:Mn4+ phosphors was investigated by employing X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy, respectively. The results indicate that adding H3BO3 flux can improve the luminescence intensity and morphology, and reduce the synthesis temperature of the Sr2MgAl22O36 phosphor. The formation temperature of pure-phase Sr2MgAl22O36 was significantly decreased when H3BO3 flux as introduced. The excited state lifetime of the Sr2MgAl22O36:1.2 mol% Mn4+ phosphor by the addition of 2.0 wt% H3BO3 was ~1.02 ms. We demonstrated the potential of these phosphors to enhance sunlight harvesting by agricultural light conversion film testing. We propose that films containing the Sr2MgAl22O36:1.2 mol% Mn4+ phosphor can be applied to increase the production of agricultural plants.
Co-reporter:Jiangling He, Youling He, Jianle Zhuang, Haoran Zhang, Bingfu Lei, Yingliang Liu
Optical Materials 2016 Volume 62() pp:458-464
Publication Date(Web):December 2016
DOI:10.1016/j.optmat.2016.10.036
•It is the first report that direct recombination of CDs and Eu3+ solutions.•Tunable photoluminescence can meet the variable light component requirements for different species of plants.•CDs can be mixed with Eu3+ solutions under the reaction of PVA to prepare the light conversion film.In this work, blue-light-emitting carbon dots (CDs) were composited with red-light-emitting europium ions (Eu3+) solutions under the synergistic reaction of polyvinyl alcohol (PVA) to prepare the light conversion film. The formation mechanism of Eu3+/CDs/PVA film was detailedly discussed. It is the first report that this composite was synthesized through direct recombination of CDs and Eu3+ solutions instead of traditional methods based on Eu3+ coordination compound. Furthermore, tunable photoluminescence property can be successfully achieved by controlling the ratio of CDs to doped Eu3+, this property can meet the variable light component requirements for different species of plants.It is the first report that this composite was synthesized through direct recombination of CDs and Eu3+ solutions instead of traditional methods based on Eu3+ coordination compound. Tunable photoluminescence property can be successfully achieved by controlling the ratio of CDs to doped-Eu3+, this property can meet the variable light component requirements for different species of plants.
Co-reporter:Wei Li, Haoran Zhang, Shi Chen, Yingliang Liu, Jianle Zhuang, Bingfu Lei
Biosensors and Bioelectronics 2016 Volume 86() pp:706-713
Publication Date(Web):15 December 2016
DOI:10.1016/j.bios.2016.07.034
•The 4-NP imprinted ratiometric fluorescence sensors were constructed by incorporating carbon dots (CDs) and YVO4: Eu3+ nanoparticles (NPs) within silica networks.•The obtained ratiometric fluorescence sensors have a linear range of 0-12.0 μM and the limit of detection as low as 0.15 μM in the determination of 4-NP.A facilely prepared ratiometric fluorescent molecularly imprinted sensor has been constructed for highly sensitive and selective detection of 4-nitrophenol (4-NP) using carbon dots (CDs) as the target sensitive fluorophore and YVO4: Eu3+ nanoparticles (NPs) as the reference fluorophore. Through the hydrolysis and condensation reactions of the silica precursor, CDs and YVO4 Eu3+ NPs can be incorporated into silica networks through silylation reaction by one pot synthesis procedure. The as-prepared fluorescent molecularly imprinted sensor shows characteristic fluorescence emissions of CDs (blue) and YVO4:Eu3+ (red) under a single excitation wavelength. With the addition of 4-NP, the fluorescence of CDs is selectively quenched, resulting in the ratiometric fluorescence response. Under optimum conditions, the proposed sensor exhibits a high sensitivity with a linear range from 0 to 12.0 μM and shows the limit of detection as low as 0.15 μM in the determination of 4-NP, which is probably benefits from the tailor-made imprinted cavities for binding 4-NP. Furthermore, the proposed method was successfully applied for the determination of 4-NP in real water samples and human urine samples with great potentials for monitoring of 4-NP in environmental application.
Co-reporter:Jin Wang, Haoran Zhang, Bingfu Lei, Zhiguo Xia, Hanwu Dong, Yingliang Liu, Mingtao Zheng and Yong Xiao
Journal of Materials Chemistry A 2015 vol. 3(Issue 17) pp:4445-4451
Publication Date(Web):11 Mar 2015
DOI:10.1039/C5TC00236B
Red-emitting CaAlSiN3:Eu2+ phosphors with different doping contents have been synthesized by solid-state reaction using calcium hydride as a calcium source. The emergence of persistent luminescence in CaAlSiN3:Eu2+ was originated from electron traps introduced by the partial substitutions of O in N sites to form positive trap levels at low Eu2+ concentration. The broad thermoluminescence emission bands indicated multiple trap levels, in which the shallow traps were mainly responsible for the red persistent luminescence; besides, the deep trap electrons could be efficiently released under extra NIR (980 nm) stimulation, resulting in enhanced photoluminescence and phosphorescence. It is expected that the enhanced emission under UV-NIR simultaneous excitation may be a promising technique to investigate the trap distributions in optical energy storage materials.
Co-reporter:Yonghao Chen, Bingfu Lei, Mingtao Zheng, Haoran Zhang, Jianle Zhuang and Yingliang Liu
Nanoscale 2015 vol. 7(Issue 47) pp:20142-20148
Publication Date(Web):05 Nov 2015
DOI:10.1039/C5NR05637C
A unique dual-emitting core–shell carbon dot–silica–phosphor (CDSP) was constructed from carbon dots (CDs), tetraethoxysilane (TEOS) and Sr2Si5N8:Eu2+ phosphor through a one-pot sol–gel method. Blue emitting CDs uniformly disperse in the silica layer covering the orange emitting phosphor via a polymerization process, which makes CDSP achieve even white light emission. Tunable photoluminescence of CDSP is observed and the preferable white light emission is achieved through changing the excitation wavelength or controlling the mass ratio of the phosphor. When CDSP powders with a phosphor rate of 3.9% and 5.1% are excited at a wavelength of 400 nm, preferable white light emission is observed, with Commission Internationale de l'Eclairage (CIE) coordinates of (0.32, 0.32) and (0.34, 0.32), respectively. Furthermore, CDSP can mix well with epoxy resin to emit strong and even white light, and based on this, a CDSP-based white LED with a high colour rendering index (CRI) of 94 was fabricated.
Co-reporter:Jin Wang, Haoran Zhang, Yingliang Liu, Hanwu Dong, Bingfu Lei, Mingtao Zheng, Yong Xiao, Mingying Peng and Jing Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 37) pp:9572-9579
Publication Date(Web):18 Aug 2015
DOI:10.1039/C5TC01849H
Probing intrinsic luminescence behaviors in known inorganic hosts is still of great importance to understand corresponding mechanisms and guide their possible applications. Nitride phosphor Ba2Si5N8:Eu2+, which shows interesting reddish-orange persistent luminescence but more famous for phosphor-conversion in white-LEDs, lacks adequate inquiries about two-peak emission, the full temperature range of thermal quenching and trap distribution. In this article, temperature-dependent photoluminescence, afterglow decay curves and photo-stimulated persistent luminescence of Ba2Si5N8:Eu2+ phosphors were investigated in detail. Evaluation of energy transfer at two emitting sites and luminescence quenching was based on careful investigation of photoluminescence at various temperatures. Furthermore, we proposed an integrated temperature-dependent afterglow decay curve method to estimate the trap density distribution in Ba2Si5N8:Eu2+ phosphor, accompanied by thermo-luminescence and photo-stimulated persistent luminescence analysis. Results indicate that integrating afterglow decay curves of various temperatures can be a useful attempt to detect trap distribution in charge carrier trapped materials.
Co-reporter:Haoran Zhang, Hanwu Dong, Bingfu Lei, Peng Wang, Jinfang Li, Yingliang Liu, Jing Wang, Yong Xiao, Mingtao Zheng, Jianxin Meng
Optical Materials 2014 Volume 36(Issue 11) pp:1846-1849
Publication Date(Web):September 2014
DOI:10.1016/j.optmat.2014.02.029
•Single phase of Ca2Si5N8:Eu2+, Tm3+, Dy3+ tridoped phosphor was obtained.•Effects of Dy3+ on the luminescent properties of CSN:E,T,D have been investigated.•Enhanced performance of CSN:E,T,D phosphor by co-doping with Dy3+ was achieved.•Balanced defect trap’s micro-environment is helpful for enhanced performance.Two types of reddish-orange afterglow emitting nitride phosphors Ca2Si5N8:Eu2+, Tm3+ (CSN:E, T) and Ca2Si5N8:Eu2+, Tm3+, Dy3+ (CSN:E, T, D) were synthesized via a solid-state reaction route and were comparatively investigated. Comparing with the di-doped CSN:E, T phosphor, the tri-doped CSN:E, T, D samples show higher afterglow intensity and longer duration time which can be attributed to the balanced defect micro-environment caused by the presence of Dy3+.
Co-reporter:Jin Wang, Haoran Zhang, Bingfu Lei, Hanwu Dong, Haiming Zhang, Yingliang Liu, Nuolin Lai, Yun Fang, Zhijie Chen
Optical Materials 2014 Volume 36(Issue 11) pp:1855-1858
Publication Date(Web):September 2014
DOI:10.1016/j.optmat.2014.04.048
•Nitride phosphor SrCaSi5N8: Eu2+, Tm3+ was synthesized by solid state reaction.•The phosphor showed strong red emission with broad peak half-width.•Excellent persistent luminescence was observed due to suitable traps depth.•Interesting photo-stimulated luminescence with short response time, erasable and rewriting ability were observed.The red persistent and photo-stimulated luminescent (PSL) nitride phosphor, SrCaSi5N8: Eu2+, Tm3+ solid solution, had been synthesized through conventional high temperature solid-state reaction. The SrCaSi5N8: Eu2+, Tm3+ phosphor shows strong photoluminescence (PL) and weak PSL (λem = 647 nm), both originating from the 4f65d–4f7 transition of Eu2+. Thermoluminescence (TL) glow curves measured at various stimulating conditions (UV excitation, in dark, laser stimulation after UV irradiation) show the same peak positions at 345 K and 360 K but great differences in the intensities. The afterglow decay curve presents excellent long-lasting red phosphorescence with a decay time of 30 min (⩾0.32 mcd/m2) after turning off the activating light. Moreover, the laser stimulated luminescence spectra, which feature sharp rising and falling edges (monitored at 647 nm) as the infrared laser diode (980 nm) excitation was turned on and off periodically, exhibit interesting rapidly responsive, erasable and rewritable abilities.
Co-reporter:Haoran Zhang, Zhiping Xue, Bingfu Lei, Hanwu Dong, Haiming Zhang, Suqing Deng, Mingtao Zheng, Yingliang Liu, Yong Xiao
Optical Materials 2014 Volume 36(Issue 11) pp:1802-1807
Publication Date(Web):September 2014
DOI:10.1016/j.optmat.2014.02.010
•The PLNS were fabricated by treating blocky SrAl2O4 phosphors via a special top-down method.•This way is simple and the final products with excellent luminescent properties compared with other methods.•The PLNS show similar photoluminescence intensity compared with commercial counterpart.•The PLNS have potential applications in optical fiber temperature sensor and bioimaging.By using commercial SrAl2O4:Eu2+,Dy3+ phosphor as raw material, we have developed a novel and simple top-down method to fabricate SrAl2O4:Eu2+,Dy3+ nanosheets that are useful for potential practical applications, especially as fluorescent labels for biomolecules and mechano-optical nano-devices. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) results demonstrate that the treated samples are still pure-phase of SrAl2O4:Eu2+,Dy3+. The field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results indicate that the treated SrAl2O4:Eu2+,Dy3+ phosphors are built up by nanosheets bundles. Excitation and emission spectra, afterglow emission spectra and decay curves are used to analyze the luminescence properties of SrAl2O4:Eu2+,Dy3+ nanosheets, and the results show that, compared with commercial samples, the treated samples show similar spectra characteristic including the spectra shapes and the band position. Furthermore, the fluorescence and afterglow intensity of SrAl2O4:Eu2+,Dy3+ nanosheets can be tuned linearly by changing the circumstance temperatures, which further indicates its potential applications in fiber-optical thermometer materials.
Co-reporter:Haobin Feng, Mingtao Zheng, Hanwu Dong, Bingfu Lei, Haoran Zhang, Yong Xiao, Yingliang Liu
Optical Materials 2014 Volume 36(Issue 11) pp:1787-1791
Publication Date(Web):September 2014
DOI:10.1016/j.optmat.2014.04.044
•Emission color tunable carbonaceous fluorescent nanoparticles (CFNs) were synthesized by carbonizing of silk cocoon.•Quantum yield of the CFNs is as high as 23%.•Hybrid CFNs/PVA thin film was obtained.•Afterglow emission from hybrid CFNs/PVA thin film was observed for the first time.Carbonaceous fluorescent nanoparticles (CFNs) with broad particle distribution were synthesized by thermal-treatment using carbonation of silk cocoon as raw materials. The experimental results showed tunable emission wavelength of the nanoparticles. The quantum yield of the CFNs was calculated to be 23%. A CFNs/PVA hybrid thin film was prepared from a blend of the CFNs with polyvinyl alcohol (PVA) showing interesting green afterglow which could be observed by naked eyes. The afterglow spectrum revealed that the CFNs/PVA thin film had a broad afterglow emission peak located at 520 nm. The afterglow intensity decay curve of the film showed visually recognizable period longer than 140 s. The PVA–PVA hydrogen bonding in the PVA matrix may play a key role for the afterglow.
Co-reporter:Jinlan Qin, Chaofan Hu, Bingfu Lei, Jinfang Li, Yingliang Liu, Shuiping Ye, Miaozhu Pan
Journal of Materials Science & Technology 2014 Volume 30(Issue 3) pp:290-294
Publication Date(Web):March 2014
DOI:10.1016/j.jmst.2013.08.009
The yellow SrSi2O2N2:Eu2+ phosphor has been synthesized by using a simple solid-state reaction method with Sr2SiO4:Eu2+ as the precursor. It shows a broad excitation band extending from 250 to 520 nm and an asymmetric emission band with a main peak at about 550 nm. The emission intensity of the SrSi2O2N2:Eu2+ is about 1.2 times higher than the commercial yellow phosphor YAG:Ce3+ (P46-Y3). The temperature-dependent luminescence characteristic of SrSi2O2N2:Eu2+ has been investigated in this paper. With increasing temperature, the emission band of SrSi2O2N2:Eu2+ shows anomalous blue-shift along with decreasing emission intensity and the broadening full width at half maximum (FWHM). Particularly, compared with YAG:Ce3+ (P46-Y3), the yellow SrSi2O2N2:Eu2+ phosphors exhibit higher thermal stability due to their weaker electron-phonon coupling strength (1.1), lower stokes shift (0.0576 eV) and larger activation energy (0.288 eV). All these results indicate that SrSi2O2N2:Eu2+ yellow phosphors have potential application for white light-emitting diodes (LEDs). What's more, an energy level scheme is constructed to explain the anomalous blue-shift phenomenon.
Co-reporter:Jinlan Qin, Haoran Zhang, Bingfu Lei, Hanwu Dong, Yingliang Liu, Jianxin Meng, Mingtao Zheng, Yong Xiao
Journal of Luminescence 2014 152() pp: 230-233
Publication Date(Web):
DOI:10.1016/j.jlumin.2013.10.001
Co-reporter:Suqing Deng, Zhiping Xue, Qu Yang, Yingliang Liu, Bingfu Lei, Yong Xiao, Mingtao Zheng
Applied Surface Science 2013 Volume 282() pp:315-319
Publication Date(Web):1 October 2013
DOI:10.1016/j.apsusc.2013.05.125
Highlights
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A facile combustion method has been developed to modify phosphors.
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MAl2B2O7 layer was formed on the surface of aluminate phosphors.
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Little influence occurred on the luminescence property.
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Water resistance of the phosphors was enhanced greatly.
Co-reporter:Zhiping XUE, Suqing DENG, Yingliang LIU, Bingfu LEI, Yong XIAO, Mingtao ZHENG
Journal of Rare Earths 2013 Volume 31(Issue 3) pp:241-246
Publication Date(Web):March 2013
DOI:10.1016/S1002-0721(12)60265-8
SrAl2O4:Eu2+,Dy3+ hollow microspheres were successfully prepared through a facile and mild solvothermal co-precipitation combining with a postcalcining process. The structure and particle morphology were investigated by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM) pictures, respectively. The mechanism for the formation of spherical SrAl2O4:Eu2+,Dy3+ phosphor was preliminary presented. After being irradiated with ultraviolet (UV) light, the spherical phosphor emitted long-lasting green phosphorescence. Both the photoluminescence (PL) spectra and luminance decay, compared with that of commercial bulky powders, revealed that the phosphors had efficient luminescent and long lasting properties. It was considered that the SrAl2O4:Eu2+,Dy3+ hollow microspheres had promising long-lasting phosphorescence with potential scale-dependent applications in photonic devices.Schematic illustration of growth process
Co-reporter:Suqing Deng, Zhiping Xue, Yingliang Liu, Bingfu Lei, Yong Xiao, Mingtao Zheng
Journal of Alloys and Compounds 2012 Volume 542() pp:207-212
Publication Date(Web):25 November 2012
DOI:10.1016/j.jallcom.2012.07.060
A red long-lasting phosphorescent material, monodisperse Y2O2S:Eu3+, Mg2+, Ti4+ hollow nanospheres have been prepared successfully by a thiourea-based homogeneous precipitation combining with a postcalcining process. Self-assembly and Ostwald ripening process occured to form hollow structure of amorphous precursors. The crystalstructure and particle morphology were investigated by the X-ray diffraction (XRD) patterns, Fourier Transform Infrared (FT-IR) spectra, scanning and transmission electron microscopy (SEM and TEM) pictures, respectively. A possible growth mechanism was proposed to reveal the formation process. Luminescence properties of the Y2O2S:Eu3+, Mg2+, Ti4+ hollow nanosphere compared with bulk material were analyzed by measuring the excitation spectra, emission spectra, afterglow decay curve and thermoluminescence curve. It was considered that this synthetic route may have potential applications for fabricating other lanthanide oxysulfides.Graphical abstractHighlights► Self-assembly and Ostwald ripening process occured to form hollow structure of amorphous precursors. ► The hollow phosphor with diameters of 90–150 nm inherited the sphere-like shape from the precursor after calcined at CS2 atmosphere. ► The long-lasting phosphorescence was due to the persistent energy transfer from the traps to the Ti4+ and Mg2+ ions.
Co-reporter:Youling He, Jiangling He, Haoran Zhang, Yingliang Liu, Bingfu Lei
Journal of Colloid and Interface Science (15 June 2017) Volume 496() pp:
Publication Date(Web):15 June 2017
DOI:10.1016/j.jcis.2017.02.013
Owning to the hydrogen-band interactions, blue-light-emitting luminescent carbon dots (CDs) synthesized by one-pot hydrothermal treatment were successfully assembled into Eu3+ doped mesoporous aluminas (MAs). Interesting, dual-emissive CDs/MAs co-doped materials with higher quantum yield (QY), long-term stability, mesoporous structure, high thermal stability, and large surface areas were obtained. Furthermore, the obtained CDs/MAs co-doped materials possessed tunable color, and excellent temperature sensitivity due to the existing of energy transfer between CDs and Eu3+ ion. The energy transfer efficiency (η) and energy transfer probability (P) for CDs/Eu3+ co-doped materials possessed a monotonous tendency with the change of Eu3+ content. More importantly, the dual-emissive colors can be regularly adjusted through regulating their excitation wavelength or relative mass ratio. In addition, the emission intensity of the CDs/MAs co-doped materials gradually decreased with increasing temperature showing the clear temperature dependence, this dual-emissive thermometer was with high sensitivity, owning a great fitted curve in the range from 100 to 360 K under a single wavelength excitation.
Co-reporter:Haiming Zhang, Haoran Zhang, Yingliang Liu, Bingfu Lei, Jiankun Deng, Wei-Ren Liu, Yuan Zeng, Lingling Zheng, Minyi Zhao
Materials Chemistry and Physics (1 June 2017) Volume 193() pp:302-310
Publication Date(Web):1 June 2017
DOI:10.1016/j.matchemphys.2017.02.042
Co-reporter:Yonghao Chen, Jiangling He, Chaofan Hu, Haoran Zhang, Bingfu Lei and Yingliang Liu
Journal of Materials Chemistry A 2017 - vol. 5(Issue 25) pp:NaN6250-6250
Publication Date(Web):2017/05/23
DOI:10.1039/C7TC01615H
Phosphorescence is difficult to be observed from carbon dot powder due to the deliquescence and self-quenching in the aggregation state. In this study, aggregation-induced room temperature phosphorescence (RTP) is first reported in self-quenching-resistant nitrogen-doped carbon dot powder, which is suggested to take advantage of the moisture-resistance, rigidization and oxygen-barrier induced by PVA-chains. Furthermore, the optical mechanism of RTP as well as fluorescence is investigated through the abnormal excitation-responsive phenomena, and the potential application in temperature sensing is also preliminarily evaluated. This study may benefit in developing phosphorescence from undesirable aggregation through structure design and exploiting emerging applications for carbon dots.
Co-reporter:Jin Wang, Haoran Zhang, Bingfu Lei, Zhiguo Xia, Hanwu Dong, Yingliang Liu, Mingtao Zheng and Yong Xiao
Journal of Materials Chemistry A 2015 - vol. 3(Issue 17) pp:NaN4451-4451
Publication Date(Web):2015/03/11
DOI:10.1039/C5TC00236B
Red-emitting CaAlSiN3:Eu2+ phosphors with different doping contents have been synthesized by solid-state reaction using calcium hydride as a calcium source. The emergence of persistent luminescence in CaAlSiN3:Eu2+ was originated from electron traps introduced by the partial substitutions of O in N sites to form positive trap levels at low Eu2+ concentration. The broad thermoluminescence emission bands indicated multiple trap levels, in which the shallow traps were mainly responsible for the red persistent luminescence; besides, the deep trap electrons could be efficiently released under extra NIR (980 nm) stimulation, resulting in enhanced photoluminescence and phosphorescence. It is expected that the enhanced emission under UV-NIR simultaneous excitation may be a promising technique to investigate the trap distributions in optical energy storage materials.
Co-reporter:Jin Wang, Haoran Zhang, Yingliang Liu, Hanwu Dong, Bingfu Lei, Mingtao Zheng, Yong Xiao, Mingying Peng and Jing Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 37) pp:NaN9579-9579
Publication Date(Web):2015/08/18
DOI:10.1039/C5TC01849H
Probing intrinsic luminescence behaviors in known inorganic hosts is still of great importance to understand corresponding mechanisms and guide their possible applications. Nitride phosphor Ba2Si5N8:Eu2+, which shows interesting reddish-orange persistent luminescence but more famous for phosphor-conversion in white-LEDs, lacks adequate inquiries about two-peak emission, the full temperature range of thermal quenching and trap distribution. In this article, temperature-dependent photoluminescence, afterglow decay curves and photo-stimulated persistent luminescence of Ba2Si5N8:Eu2+ phosphors were investigated in detail. Evaluation of energy transfer at two emitting sites and luminescence quenching was based on careful investigation of photoluminescence at various temperatures. Furthermore, we proposed an integrated temperature-dependent afterglow decay curve method to estimate the trap density distribution in Ba2Si5N8:Eu2+ phosphor, accompanied by thermo-luminescence and photo-stimulated persistent luminescence analysis. Results indicate that integrating afterglow decay curves of various temperatures can be a useful attempt to detect trap distribution in charge carrier trapped materials.
