Fluorescent carbon dots(CDs)have been widely studied in biosensing,imaging,information encryption,and optoelectronic devices due to excellent optical properties,such as photostability,tunable luminescence range,and re...Fluorescent carbon dots(CDs)have been widely studied in biosensing,imaging,information encryption,and optoelectronic devices due to excellent optical properties,such as photostability,tunable luminescence range,and resistance to photobleaching.In recent years,CDs have been explored for use in agriculture.Based on their light harvest and light conversion capacity,as well as their characteristics of easy synthesis and low toxicity,CDs show great potential in improving crop photosynthesis.In addition,CDs can also be used for smart and anticounterfeiting packing,food safety detection,and preservation of crops after harvest.In this study,the application of CDs with excellent optical properties in crops has been summarized,including preharvest processes(photosynthesis and plant imaging),and postharvest processes(crop preservation and food safety).Then the toxicity of CDs to crops is introduced.Finally,the present challenges and future prospects are discussed.展开更多
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 asymme...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 SrSi202N2：Eu2＋ is about 1.2 times higher than the commercial yellow phosphor YAG：Ce3＋ （P46-Y3）. The temperature- dependent luminescence characteristic of SrSi202N2：Eu2＋ has been investigated in this paper. With increasing temperature, the emission band of SrSi202N2：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 SrSi202N2：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 SrSi202N2：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.展开更多
As one of the most promising fluorescent nanomaterials, carbon dots(CDs) have been extensively studied for their fluorescent properties in solution. However, research on the synthesis of multicolor solid-state fluores...As one of the most promising fluorescent nanomaterials, carbon dots(CDs) have been extensively studied for their fluorescent properties in solution. However, research on the synthesis of multicolor solid-state fluorescence(SSF) CDs(from blue to red) is rarely reported. Herein, we used o-phenylenediamine, mphenylenediamine and p-phenylenediamine with dithiosalicylic acid(DTSA) in the solvothermal reaction using acetic acid as a solvent to obtain aggregation-induced emissive(AIE) CDs of red(620 nm), green(520 nm), and blue(478 nm), respectively. XPS spectra and TEM image show that with the red-shift of luminescence, the particle size and content of C=O of the CDs gradually increases. Finally, based on the non-matrix solid-state multicolor luminescence characteristics of CDs, the application of white light LED devices is realized. Besides, based on the fat-soluble properties of CDs, fingerprint detection applications are realized.展开更多
基金This work was supported by the National Natural Science Foundation of China(11874021,61675072,81601534 and 51402207)the Science and Technology Project of Guangdong Province of China(2017A020215059)the Science and Technology Project of Guangzhou City(201904010323).
基金supported by the National Natural Science Foundation of China(Nos.12174119 and 52172142)Science and Technology Program of Guangzhou,China(No.202103000059).
文摘Fluorescent carbon dots(CDs)have been widely studied in biosensing,imaging,information encryption,and optoelectronic devices due to excellent optical properties,such as photostability,tunable luminescence range,and resistance to photobleaching.In recent years,CDs have been explored for use in agriculture.Based on their light harvest and light conversion capacity,as well as their characteristics of easy synthesis and low toxicity,CDs show great potential in improving crop photosynthesis.In addition,CDs can also be used for smart and anticounterfeiting packing,food safety detection,and preservation of crops after harvest.In this study,the application of CDs with excellent optical properties in crops has been summarized,including preharvest processes(photosynthesis and plant imaging),and postharvest processes(crop preservation and food safety).Then the toxicity of CDs to crops is introduced.Finally,the present challenges and future prospects are discussed.
基金the financial supports of the National Natural Science Foundations of China (Nos.50903038, 21171071, 51203053, and 21071063)the project sponsored by SRF for ROCS, SEM (No. [2011] 1139)the project of the combination of Industry and Research by the Ministry of Education and Guangdong Province (No. 2012B091100181)
文摘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 SrSi202N2：Eu2＋ is about 1.2 times higher than the commercial yellow phosphor YAG：Ce3＋ （P46-Y3）. The temperature- dependent luminescence characteristic of SrSi202N2：Eu2＋ has been investigated in this paper. With increasing temperature, the emission band of SrSi202N2：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 SrSi202N2：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 SrSi202N2：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.
基金supported by the National Natural Science Foundation of China (No. 51602108)the Guangdong Basic and Applied Basic Research Foundation (Nos. 2020A1515011210, 2017A030313256)Guangzhou Science and Technology Project (Nos. 202007020005, 202102080288)。
文摘As one of the most promising fluorescent nanomaterials, carbon dots(CDs) have been extensively studied for their fluorescent properties in solution. However, research on the synthesis of multicolor solid-state fluorescence(SSF) CDs(from blue to red) is rarely reported. Herein, we used o-phenylenediamine, mphenylenediamine and p-phenylenediamine with dithiosalicylic acid(DTSA) in the solvothermal reaction using acetic acid as a solvent to obtain aggregation-induced emissive(AIE) CDs of red(620 nm), green(520 nm), and blue(478 nm), respectively. XPS spectra and TEM image show that with the red-shift of luminescence, the particle size and content of C=O of the CDs gradually increases. Finally, based on the non-matrix solid-state multicolor luminescence characteristics of CDs, the application of white light LED devices is realized. Besides, based on the fat-soluble properties of CDs, fingerprint detection applications are realized.
