Going beyond an improved colour gamut,an asymmetric colour contrast,which depends on the viewing direction,and its ability to readily deliver information could create opportunities for a wide range of applications,suc...Going beyond an improved colour gamut,an asymmetric colour contrast,which depends on the viewing direction,and its ability to readily deliver information could create opportunities for a wide range of applications,such as nextgeneration optical switches,colour displays,and security features in anti-counterfeiting devices.Here,we propose a simple Fabry–Perot etalon architecture capable of generating viewing-direction-sensitive colour contrasts and encrypting pre-inscribed information upon immersion in particular solvents(optical camouflage).Based on the experimental verification of the theoretical modelling,we have discovered a completely new and exotic optical phenomenon involving a tuneable colour switch for viewing-direction-dependent information delivery,which we define as asymmetric optical camouflage.展开更多
We demonstrate the dipole-assisted carrier transport properties of bis(trifluoromethane)sulfonamide(TFSI)-treated O-ReS_(2) field-effect transistors.Pristine ReS_(2) was compared with defect-mediated ReS_(2) to confir...We demonstrate the dipole-assisted carrier transport properties of bis(trifluoromethane)sulfonamide(TFSI)-treated O-ReS_(2) field-effect transistors.Pristine ReS_(2) was compared with defect-mediated ReS_(2) to confirm whether the presence of defects on the interface enhances the interaction between O-ReS_(2) and TFSI molecules.Prior to the experiment,density functional theory(DFT)calculation was performed,and the result indicated that the charge transfer between TFSI and O-ReS_(2) is more sensitive to external electric fields than that between TFSI and pristine ReS_(2).After TFSI treatment,the drain current of O-ReS_(2) FET was significantly increased up to 1,113.4 times except in the range of−0.32–0.76 V owing to Schottky barrier modulation from dipole polarization of TFSI molecules,contrary to a significant degradation in device performance in pristine ReS_(2) FET.Moreover,in the treated O-ReS_(2) device,the dipole direction was highly influenced by the voltage sweep direction,generating a significant area of hysteresis in I–V and transfer characteristics,which was further verified by the surface potential result.Furthermore,the dipole state was enhanced according to the wavelength of the light source and photocurrent.These results indicate that TFSI-treated ReS_(2) FET has large potential for use as next-generation memristor,memory,and photodetector.展开更多
Palladium is the most prominent material in both scientific and industrial research on gas storage,purification,detection,and catalysis due to its unique properties as a catalyst and hydrogen absorber.Advancing the dy...Palladium is the most prominent material in both scientific and industrial research on gas storage,purification,detection,and catalysis due to its unique properties as a catalyst and hydrogen absorber.Advancing the dynamic optical phenomena of palladium reacting with hydrogen,transduction of the gas-matter reaction into light-matter interaction is attempted to visualize the dynamic surface chemistry and reaction behaviors.The simple geometry of the metal-dielectric-metal structure,Fabry-Perot etalon,is employed for a colorimetric reactor,to display the catalytic reaction of the exposed gas via water-film/bubble formation at the dielectric/palladium interface.The adsorption/desorption behavior and catalytic reaction of hydrogen and oxygen on the palladium surface display highly repeatable and dramatic color changes based on two distinct water formation trends:the foggy effect by water bubbles and the whiteout effect by water film formation.Simulations and experiments demonstrate the robustness of the proposed Fabry-Perot etalon as an excellent platform for monitoring the opto-physical phenomena driven by heterogeneous catalysis.展开更多
基金supported in part by KIST intramural grants(Nos.2E30506,2V07880,and 2E30140)supported by the Basic Science Research Programme through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(2020R1A4A1019518)+1 种基金supported by NRF grant funded by MSIT(2020R1A2B5B03002005)support from the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2020R1C1C1013474).
文摘Going beyond an improved colour gamut,an asymmetric colour contrast,which depends on the viewing direction,and its ability to readily deliver information could create opportunities for a wide range of applications,such as nextgeneration optical switches,colour displays,and security features in anti-counterfeiting devices.Here,we propose a simple Fabry–Perot etalon architecture capable of generating viewing-direction-sensitive colour contrasts and encrypting pre-inscribed information upon immersion in particular solvents(optical camouflage).Based on the experimental verification of the theoretical modelling,we have discovered a completely new and exotic optical phenomenon involving a tuneable colour switch for viewing-direction-dependent information delivery,which we define as asymmetric optical camouflage.
基金This work was supported by the national research foundation of Korea(NRF)grant funded by the Korea government(MIST)(Nos.NRF-2019R1A2C2090443,NRF-2017M3A7B4041987,NRF-2020M3F6A1081009,and NRF-2017M1A3A3A02015033)Korea Electric Power Corporation.(Grant No.R19XO01-23).
文摘We demonstrate the dipole-assisted carrier transport properties of bis(trifluoromethane)sulfonamide(TFSI)-treated O-ReS_(2) field-effect transistors.Pristine ReS_(2) was compared with defect-mediated ReS_(2) to confirm whether the presence of defects on the interface enhances the interaction between O-ReS_(2) and TFSI molecules.Prior to the experiment,density functional theory(DFT)calculation was performed,and the result indicated that the charge transfer between TFSI and O-ReS_(2) is more sensitive to external electric fields than that between TFSI and pristine ReS_(2).After TFSI treatment,the drain current of O-ReS_(2) FET was significantly increased up to 1,113.4 times except in the range of−0.32–0.76 V owing to Schottky barrier modulation from dipole polarization of TFSI molecules,contrary to a significant degradation in device performance in pristine ReS_(2) FET.Moreover,in the treated O-ReS_(2) device,the dipole direction was highly influenced by the voltage sweep direction,generating a significant area of hysteresis in I–V and transfer characteristics,which was further verified by the surface potential result.Furthermore,the dipole state was enhanced according to the wavelength of the light source and photocurrent.These results indicate that TFSI-treated ReS_(2) FET has large potential for use as next-generation memristor,memory,and photodetector.
基金National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2021R1A2C2009236 and No.2020M3H5A108110413)Y.-S.R.acknowledges support from a grant of the Information and Communications Promotion Fund(ICT promotion fund)through the National IT Industry Promotion Agency(NIPA),and Korea University Grant(K2311801)Y.P acknowledges support from KIST Institutional grants(No.2E32451 and 2V09640).
文摘Palladium is the most prominent material in both scientific and industrial research on gas storage,purification,detection,and catalysis due to its unique properties as a catalyst and hydrogen absorber.Advancing the dynamic optical phenomena of palladium reacting with hydrogen,transduction of the gas-matter reaction into light-matter interaction is attempted to visualize the dynamic surface chemistry and reaction behaviors.The simple geometry of the metal-dielectric-metal structure,Fabry-Perot etalon,is employed for a colorimetric reactor,to display the catalytic reaction of the exposed gas via water-film/bubble formation at the dielectric/palladium interface.The adsorption/desorption behavior and catalytic reaction of hydrogen and oxygen on the palladium surface display highly repeatable and dramatic color changes based on two distinct water formation trends:the foggy effect by water bubbles and the whiteout effect by water film formation.Simulations and experiments demonstrate the robustness of the proposed Fabry-Perot etalon as an excellent platform for monitoring the opto-physical phenomena driven by heterogeneous catalysis.
