Surface-enhanced Raman spectroscopy （SERS） is a fast analytical technique for trace chemicals; however, it requires the active SERS-substrates to adsorb analytes, thus limiting target species to those with the desir...Surface-enhanced Raman spectroscopy （SERS） is a fast analytical technique for trace chemicals; however, it requires the active SERS-substrates to adsorb analytes, thus limiting target species to those with the desired affinity for substrates. Here we present networked polyacrylic acid sodium salt （PAAS） film entrapped Ag-nanocubes （denoted as Ag-nanocubes@PAAS） as an effective SERS-substrate for analytes with and without high affinity. Once the analyte aqueous solution is cast on the dry Ag-nanocubes@PAAS substrate, the bibulous PAAS becomes swollen forcing the Ag-nanocubes loose, while the analytes diffuse in the interstices among the Ag-nanocubes. When dried, the PAAS shrinks and pulls the Ag-nanocubes back to their previous aggregated state, while the PAAS network ＂detains＂ the analytes in the small gaps between the Ag-nanocubes for SERS detection. The strategy has been proven effective for not only single- analytes but also multi-analytes without strong affinity for Ag, showing its potential in SERS-based simultaneous multi-analyte detection of both adsorbable and non-adsorbable pollutants in the environment.展开更多
Tin oxide（SnO2） is a promising wide bandgap semiconductor for next generation ultraviolet（UV） nonpolar optoelectronic devices applications.The development of SnO2-based optoelectronic devices is obsessed by its lo...Tin oxide（SnO2） is a promising wide bandgap semiconductor for next generation ultraviolet（UV） nonpolar optoelectronic devices applications.The development of SnO2-based optoelectronic devices is obsessed by its low exciton emission efficiency.In this study,quantum confined SnO2nanocrystals have been fabricated via pulsed laser ablation in water.The SnO2quantum dots（QDs） possess high performance exciton emission at 297-300 nm light in water.The exciton emission intensity and wavelength can be slightly tuned by laser pulse energy and irradiation time.Optical gain has been observed in SnO2QDs.Therefore,SnO2QDs can be a promising luminescence material for the realization of deep UV nanoemitter and lasing devices.展开更多
文摘Surface-enhanced Raman spectroscopy （SERS） is a fast analytical technique for trace chemicals; however, it requires the active SERS-substrates to adsorb analytes, thus limiting target species to those with the desired affinity for substrates. Here we present networked polyacrylic acid sodium salt （PAAS） film entrapped Ag-nanocubes （denoted as Ag-nanocubes@PAAS） as an effective SERS-substrate for analytes with and without high affinity. Once the analyte aqueous solution is cast on the dry Ag-nanocubes@PAAS substrate, the bibulous PAAS becomes swollen forcing the Ag-nanocubes loose, while the analytes diffuse in the interstices among the Ag-nanocubes. When dried, the PAAS shrinks and pulls the Ag-nanocubes back to their previous aggregated state, while the PAAS network ＂detains＂ the analytes in the small gaps between the Ag-nanocubes for SERS detection. The strategy has been proven effective for not only single- analytes but also multi-analytes without strong affinity for Ag, showing its potential in SERS-based simultaneous multi-analyte detection of both adsorbable and non-adsorbable pollutants in the environment.
基金the financial support of the project from the National Natural Science Foundation of China(Grant Nos.11004197,11374309,and 11104270)China Postdoctoral Science Foundation Funded Project(Grant No.2013M541847)"Hong Kong Scholars Program"(Grant Nos.XJ2011039,and 201104336)
文摘Tin oxide（SnO2） is a promising wide bandgap semiconductor for next generation ultraviolet（UV） nonpolar optoelectronic devices applications.The development of SnO2-based optoelectronic devices is obsessed by its low exciton emission efficiency.In this study,quantum confined SnO2nanocrystals have been fabricated via pulsed laser ablation in water.The SnO2quantum dots（QDs） possess high performance exciton emission at 297-300 nm light in water.The exciton emission intensity and wavelength can be slightly tuned by laser pulse energy and irradiation time.Optical gain has been observed in SnO2QDs.Therefore,SnO2QDs can be a promising luminescence material for the realization of deep UV nanoemitter and lasing devices.
