As promising electrode materials,transition metal oxides have attracted considerable attention owing to their excellent performance in electrochemical energy storage.However,their poor conductivity and fragile structu...As promising electrode materials,transition metal oxides have attracted considerable attention owing to their excellent performance in electrochemical energy storage.However,their poor conductivity and fragile structure limit their practical application.In this study,a binder-free nickel oxide/oxynitride network(NiON WS)bifunctional electrodes with cation multivalent states that exhibit high energy storage performance were synthesized for the first time.The massive active sites,high specific surface areas,and multiple cation valence states of NiON WS were advantageous for electrochemical redox reaction during its application in supercapacitors(1283.5 mF cm^(-2))and lithium-ion batteries(1345.0 mA h g^(-1)).Particularly,the NiON WS based flexible asymmetric SCs exhibit excellent capacitance and energy densities.First-principle calculations were employed to study the mechanism of the electrochemical performance improvement of NiON WS.This study demonstrates the potential of transition metal oxides electrode with high capacity and activity for electrochemical energy storage and conversion.展开更多
By modifying the salicylic-acid moiety with electron-withdrawing or –donating groups, three new terbium complexes(LⅠ·Tb, LⅡ·Tb, L·(Ⅲ)Tb) based on tripodal carboxylate ligands were synthesized. D...By modifying the salicylic-acid moiety with electron-withdrawing or –donating groups, three new terbium complexes(LⅠ·Tb, LⅡ·Tb, L·(Ⅲ)Tb) based on tripodal carboxylate ligands were synthesized. Due to different pull-push electronic effects of ligands, the fluorescence intensities of these terbium complexes significantly varied, that is: LⅡ·Tb 〉L(Ⅲ)·Tb〉 LⅠ·Tb. Meanwhile, the characteristic peaks at 492 nm(5D4→7F6) and 547 nm(5 D4→7F5) showed "Off–On–Off" fluorescence response to various p H conditions,which indicated that all of them can be used as the highly sensitive pH fluorescent probes. Notably, using LⅡ·Tb with the best fluorescence performance as a probe, some patients' urine samples can be easily monitored through the response triggered by pH value. Therefore, LⅡ·Tb has the potential to auxiliarily diagnose some diseases in clinical practice through p H detection of routine urine test.展开更多
In this work,a method to acquire freestanding GaN by using low temperature(LT)-GaN layer was put forward.To obtain porous structure and increase the crystallinity,LT-GaN layers were annealed at high temperature.The mo...In this work,a method to acquire freestanding GaN by using low temperature(LT)-GaN layer was put forward.To obtain porous structure and increase the crystallinity,LT-GaN layers were annealed at high temperature.The morphology of LTGaN layers with different thickness and annealing temperature before and after annealing was analyzed.Comparison of GaN films using different LT-GaN layers was made to acquire optimal LT-GaN process.According to HRXRD and Raman results,GaN grown on 800 nm LT-GaN layer which was annealed at 1090℃ has good crystal quality and small stress.The GaN film was successfully separated from the substrate after cooling down.The self-separation mechanism of this method was discussed.Cross-sectional EBSD mapping measurements were carried out to investigate the effect of LT-buffer layer on improvement of crystal quality and stress relief.The optical property of the obtained freestanding GaN film was also determined by PL measurement.展开更多
基金supported by the National Natural Science Foundation of China,China(Contract 51872164)Natural Science Foundation of Shandong Province,China(Contract ZR2018MEM013)+1 种基金China Postdoctoral Science Foundation,China(Contract 2019TQ0172,2019M662349)Shandong Provincial Key Research and Development Program,China(Contract 2019GGX103010)。
文摘As promising electrode materials,transition metal oxides have attracted considerable attention owing to their excellent performance in electrochemical energy storage.However,their poor conductivity and fragile structure limit their practical application.In this study,a binder-free nickel oxide/oxynitride network(NiON WS)bifunctional electrodes with cation multivalent states that exhibit high energy storage performance were synthesized for the first time.The massive active sites,high specific surface areas,and multiple cation valence states of NiON WS were advantageous for electrochemical redox reaction during its application in supercapacitors(1283.5 mF cm^(-2))and lithium-ion batteries(1345.0 mA h g^(-1)).Particularly,the NiON WS based flexible asymmetric SCs exhibit excellent capacitance and energy densities.First-principle calculations were employed to study the mechanism of the electrochemical performance improvement of NiON WS.This study demonstrates the potential of transition metal oxides electrode with high capacity and activity for electrochemical energy storage and conversion.
基金supported by the National Natural Science Foundation of China (Nos. 21572091 and 21472075)the Fundamental Research Funds for the Central Universities (No. lzujbky-2016-51) by Ministry of Education of China
文摘By modifying the salicylic-acid moiety with electron-withdrawing or –donating groups, three new terbium complexes(LⅠ·Tb, LⅡ·Tb, L·(Ⅲ)Tb) based on tripodal carboxylate ligands were synthesized. Due to different pull-push electronic effects of ligands, the fluorescence intensities of these terbium complexes significantly varied, that is: LⅡ·Tb 〉L(Ⅲ)·Tb〉 LⅠ·Tb. Meanwhile, the characteristic peaks at 492 nm(5D4→7F6) and 547 nm(5 D4→7F5) showed "Off–On–Off" fluorescence response to various p H conditions,which indicated that all of them can be used as the highly sensitive pH fluorescent probes. Notably, using LⅡ·Tb with the best fluorescence performance as a probe, some patients' urine samples can be easily monitored through the response triggered by pH value. Therefore, LⅡ·Tb has the potential to auxiliarily diagnose some diseases in clinical practice through p H detection of routine urine test.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51702226,51572153 and 51602177)the Natural Science Foundation of Shanxi Province(Grant No.201701D221078).
文摘In this work,a method to acquire freestanding GaN by using low temperature(LT)-GaN layer was put forward.To obtain porous structure and increase the crystallinity,LT-GaN layers were annealed at high temperature.The morphology of LTGaN layers with different thickness and annealing temperature before and after annealing was analyzed.Comparison of GaN films using different LT-GaN layers was made to acquire optimal LT-GaN process.According to HRXRD and Raman results,GaN grown on 800 nm LT-GaN layer which was annealed at 1090℃ has good crystal quality and small stress.The GaN film was successfully separated from the substrate after cooling down.The self-separation mechanism of this method was discussed.Cross-sectional EBSD mapping measurements were carried out to investigate the effect of LT-buffer layer on improvement of crystal quality and stress relief.The optical property of the obtained freestanding GaN film was also determined by PL measurement.