In this work,monodisperseβ-NaLuF_(4):Yb,Er microcrystals with intense upconversion emission were synthesized via a modified hydrothermal method.With the increase of reactant concentration,their production yield is in...In this work,monodisperseβ-NaLuF_(4):Yb,Er microcrystals with intense upconversion emission were synthesized via a modified hydrothermal method.With the increase of reactant concentration,their production yield is increased obviously,and the upconversion emission intensity inβ-NaLuF_(4):Yb,Er microcrystals is also enhanced significantly.The luminescence enhancement should be attributed to minimal internal OH defects,validated by a combination of analytical X-ray diffraction(XRD),energy dispersive spectrum(EDS),and Eu^(3+)structural probe measurements.We also reveal that high Na^(+):RE~(3+)ratio in theβ-NaLuF_(4):Yb,Er microcrystals prepared under Na^(~)+-rich reaction will arouse the increased repulsive energy ofβ-NaLuF_(4)microcrystals between F^(~)-and OH^(~)-anions and then facilitate the substitution of large OH^(-)ions by small F^(~)-ions under F^(~)--rich reaction conditions.Minimal OH^(-)concentrations can limit nonradiative relaxation and promote excitation energy harvesting for high upconversion efficiency.The presented results not only offer a facile method for the simultaneous production yield and luminescence intensity increase ofβ-NaREF_(4)microcrystals,but also uncover a better insight into the upconversion emission alterations,which is favorable to broaden their practical applications.展开更多
Plastic waste is generally resistant to natural degradation and has become a major environmental pollution problem globally. The pollution of ecosystems seriously affects the health and survival of organisms,including...Plastic waste is generally resistant to natural degradation and has become a major environmental pollution problem globally. The pollution of ecosystems seriously affects the health and survival of organisms,including humans. Much attention has been paid to finding suitable ways to convert plastic waste into high-value-added carbon materials. To this end, we report the high production yield(60%–85%) of carbon dots(CDs) for solid-state fluorescence(SSF) obtained by a one-step solvothermal method using waste expanded polystyrene as the precursor. The SSF mechanism of the CDs was also explored. Their emission wavelength, with a large full width at half maximum of 150–200 nm, exhibited tunable photoluminescence from white to yellow and orange. CDs powder was used to fabricate single-component white and multi-colour light-emitting diodes on UV chips. Overall, plastic waste was converted into tunable solid-state fluorescent CDs powder, which has promising applications in carbon-based lighting, by a simple solvothermal method that provides a viable method for recycling plastic waste.展开更多
基金Project supported by the National Natural Science Foundation of China(11504317,51503177)the International Partnership Program of Chinese Academy of Sciences(121522KYSB20190022)。
文摘In this work,monodisperseβ-NaLuF_(4):Yb,Er microcrystals with intense upconversion emission were synthesized via a modified hydrothermal method.With the increase of reactant concentration,their production yield is increased obviously,and the upconversion emission intensity inβ-NaLuF_(4):Yb,Er microcrystals is also enhanced significantly.The luminescence enhancement should be attributed to minimal internal OH defects,validated by a combination of analytical X-ray diffraction(XRD),energy dispersive spectrum(EDS),and Eu^(3+)structural probe measurements.We also reveal that high Na^(+):RE~(3+)ratio in theβ-NaLuF_(4):Yb,Er microcrystals prepared under Na^(~)+-rich reaction will arouse the increased repulsive energy ofβ-NaLuF_(4)microcrystals between F^(~)-and OH^(~)-anions and then facilitate the substitution of large OH^(-)ions by small F^(~)-ions under F^(~)--rich reaction conditions.Minimal OH^(-)concentrations can limit nonradiative relaxation and promote excitation energy harvesting for high upconversion efficiency.The presented results not only offer a facile method for the simultaneous production yield and luminescence intensity increase ofβ-NaREF_(4)microcrystals,but also uncover a better insight into the upconversion emission alterations,which is favorable to broaden their practical applications.
基金financially supported by the National Natural Science Foundation of China (21905253, 51973200)the China Postdoctoral Science Foundation (2018M640681, 2019T120632)
文摘Plastic waste is generally resistant to natural degradation and has become a major environmental pollution problem globally. The pollution of ecosystems seriously affects the health and survival of organisms,including humans. Much attention has been paid to finding suitable ways to convert plastic waste into high-value-added carbon materials. To this end, we report the high production yield(60%–85%) of carbon dots(CDs) for solid-state fluorescence(SSF) obtained by a one-step solvothermal method using waste expanded polystyrene as the precursor. The SSF mechanism of the CDs was also explored. Their emission wavelength, with a large full width at half maximum of 150–200 nm, exhibited tunable photoluminescence from white to yellow and orange. CDs powder was used to fabricate single-component white and multi-colour light-emitting diodes on UV chips. Overall, plastic waste was converted into tunable solid-state fluorescent CDs powder, which has promising applications in carbon-based lighting, by a simple solvothermal method that provides a viable method for recycling plastic waste.
