In the present work, we explore the solar-blind ultraviolet（UV） photodetectors（PDs） with enhanced photoresponse,fabricated on Ga/Ga2O3 nanocomposite films. Through pre-burying metal Ga layers and thermally post-an...In the present work, we explore the solar-blind ultraviolet（UV） photodetectors（PDs） with enhanced photoresponse,fabricated on Ga/Ga2O3 nanocomposite films. Through pre-burying metal Ga layers and thermally post-annealing the laminated Ga2 O3/Ga/Ga2O3 structures, Ga/Ga2O3 nanocomposite films incorporated with Ga nanospheres are obtained. For the prototype PD, it is found that the photocurrent and photoresponsivity will first increase and then decrease monotonically with the thickness of the pre-buried Ga layer increasing. Each of all PDs shows a spectrum response peak at 260 nm, demonstrating the ability to detect solar-blind UV light. Adjustable photoresponse enhancement factors are achieved by means of the surface plasmon in the nanocomposite films. The PD with a 20 nm thick Ga interlayer exhibits the best solar-blind UV photoresponse characteristics with an extremely low dark current of 8.52 p A at 10-V bias, a very high light-to-dark ratio of ～ 8 × 10~5, a large photoresponsivity of 2.85 A/W at 15-V bias, and a maximum enhancement factor of ～ 220. Our research provides a simple and practical route to high performance solar-blind UV PDs and potential applications in the field of optoelectronics.展开更多
Reducing the oil-water interfacial tension(IFT)to ultra-low is believed the primary mechanism for surfactant-based enhanced oil recovery(EOR)process.However,field trials have shown that low concentration surfactant fl...Reducing the oil-water interfacial tension(IFT)to ultra-low is believed the primary mechanism for surfactant-based enhanced oil recovery(EOR)process.However,field trials have shown that low concentration surfactant flooding can also improve oil recovery without ultra-low IFT.To clarify the mechanism behind,the currently-used surfactant,naphthenic arylsulfonate(NAS),was used to unravel its function during surfactant flooding from the horizon of micron-and nano-scale.The solubilization capacity of NAS micelle to petroleum fractions was evaluated through light absorbance strategy,smallangle neutron scattering,dynamic light scattering and transmission electron microscopy.It was found that micellar solubilization plays a significant role during the surfactant flooding.In-situ emulsification was visualized in microfluidics with three types of microchips,respectively.A series of displacement tests were carried out with NAS solution pumping into oil-saturated chip.The results show that in-situ emulsification improve oil recovery mainly through blocking and entrainment effects.Results from this work aid in understanding the interaction between surfactant solution and petroleum fractions at low surfactant concentration,which is helpful for design surfactant-based displacing system for EOR process.展开更多
Hypoxanthine(Hx)is an important freshness indicator reflecting the initial freshness of aquatic products.In this work,a novel fluorescence method was established based on cysteine functionalized copper nanoclusters(Cy...Hypoxanthine(Hx)is an important freshness indicator reflecting the initial freshness of aquatic products.In this work,a novel fluorescence method was established based on cysteine functionalized copper nanoclusters(Cys-CuNCs)for monitoring Hx in fish.The as-synthesized Cys-CuNCs exhibit favorable fluorescent property.Importantly,the fluorescence can be quenched significantly when the solution contained a small amount of hydrogen peroxide(H_(2)O_(2)),which was due to both the oxidation of H_(2)O_(2) towards Cys-CuNCs and the resulting Cu(II).Owing to that Hx can generate H_(2)O_(2) under dissolved oxygen and xanthine oxidase(XOD),a fluorescent method for Hx was established.Under the optimal conditions,the Hx concentration in the range of 8–400μmol/L has a good linear relationship with the fluorescence quenching e fficiency,and the detection limit is 0.7μmol/L.Finally,the as-established sensor was applied to determine Hx content in carp.By comparing to the total volatile basic nitrogen(TVB-N)results,the proposed method was feasible in the evaluation of carp freshness.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11674405 and 11675280)the Fund from the Laboratory of Microfabrication in Institute of Physics,Chinese Academy of Sciences
文摘In the present work, we explore the solar-blind ultraviolet（UV） photodetectors（PDs） with enhanced photoresponse,fabricated on Ga/Ga2O3 nanocomposite films. Through pre-burying metal Ga layers and thermally post-annealing the laminated Ga2 O3/Ga/Ga2O3 structures, Ga/Ga2O3 nanocomposite films incorporated with Ga nanospheres are obtained. For the prototype PD, it is found that the photocurrent and photoresponsivity will first increase and then decrease monotonically with the thickness of the pre-buried Ga layer increasing. Each of all PDs shows a spectrum response peak at 260 nm, demonstrating the ability to detect solar-blind UV light. Adjustable photoresponse enhancement factors are achieved by means of the surface plasmon in the nanocomposite films. The PD with a 20 nm thick Ga interlayer exhibits the best solar-blind UV photoresponse characteristics with an extremely low dark current of 8.52 p A at 10-V bias, a very high light-to-dark ratio of ～ 8 × 10~5, a large photoresponsivity of 2.85 A/W at 15-V bias, and a maximum enhancement factor of ～ 220. Our research provides a simple and practical route to high performance solar-blind UV PDs and potential applications in the field of optoelectronics.
基金Natural Science Foundation of China for its financial support(grant number:U1762218)
文摘Reducing the oil-water interfacial tension(IFT)to ultra-low is believed the primary mechanism for surfactant-based enhanced oil recovery(EOR)process.However,field trials have shown that low concentration surfactant flooding can also improve oil recovery without ultra-low IFT.To clarify the mechanism behind,the currently-used surfactant,naphthenic arylsulfonate(NAS),was used to unravel its function during surfactant flooding from the horizon of micron-and nano-scale.The solubilization capacity of NAS micelle to petroleum fractions was evaluated through light absorbance strategy,smallangle neutron scattering,dynamic light scattering and transmission electron microscopy.It was found that micellar solubilization plays a significant role during the surfactant flooding.In-situ emulsification was visualized in microfluidics with three types of microchips,respectively.A series of displacement tests were carried out with NAS solution pumping into oil-saturated chip.The results show that in-situ emulsification improve oil recovery mainly through blocking and entrainment effects.Results from this work aid in understanding the interaction between surfactant solution and petroleum fractions at low surfactant concentration,which is helpful for design surfactant-based displacing system for EOR process.
基金supported by the National Natural Science Foundation of China(No.31271875)the Natural Science Foundation of Zhejiang Province(No.Y16C160009)the Key Research Projects of Zhejiang(No.2515C02001),China
基金financially supported by the National Natural Science Foundation of China(32072299,21675062)the National Key R&D Program of China(2018YFD0901004)the Science and Technology Planning Project of Fujian Province,China(2020J01677)
文摘Hypoxanthine(Hx)is an important freshness indicator reflecting the initial freshness of aquatic products.In this work,a novel fluorescence method was established based on cysteine functionalized copper nanoclusters(Cys-CuNCs)for monitoring Hx in fish.The as-synthesized Cys-CuNCs exhibit favorable fluorescent property.Importantly,the fluorescence can be quenched significantly when the solution contained a small amount of hydrogen peroxide(H_(2)O_(2)),which was due to both the oxidation of H_(2)O_(2) towards Cys-CuNCs and the resulting Cu(II).Owing to that Hx can generate H_(2)O_(2) under dissolved oxygen and xanthine oxidase(XOD),a fluorescent method for Hx was established.Under the optimal conditions,the Hx concentration in the range of 8–400μmol/L has a good linear relationship with the fluorescence quenching e fficiency,and the detection limit is 0.7μmol/L.Finally,the as-established sensor was applied to determine Hx content in carp.By comparing to the total volatile basic nitrogen(TVB-N)results,the proposed method was feasible in the evaluation of carp freshness.
