In light science and applications,equally important roles are played by efficient light emitters/detectors and by the optical elements responsible for light extraction and delivery.The latter should be simple,cost eff...In light science and applications,equally important roles are played by efficient light emitters/detectors and by the optical elements responsible for light extraction and delivery.The latter should be simple,cost effective,broadband,versatile and compatible with other components of widely desired micro-optical systems.Ideally,they should also operate without high-numerical-aperture optics.Here,we demonstrate that all these requirements can be met with elliptical microlenses 3D printed on top of light emitters.Importantly,the microlenses we propose readily form the collected light into an ultra-low divergence beam(half-angle divergence below 1°)perfectly suited for ultra-longworking-distance optical measurements(600mm with a 1-inch collection lens),which are not accessible to date with other spectroscopic techniques.Our microlenses can be fabricated on a wide variety of samples,including semiconductor quantum dots and fragile van der Waals heterostructures made of novel two-dimensional materials,such as monolayer and few-layer transition metal dichalcogenides.展开更多
We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） n...We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） nanowires, monitored by the temperature and the bias voltage. At low temperature, in the Coulomb blockade regime, the current flow reveals an original cooperative multi-hopping process between 1D-segments of Au-NWs, minimising the charging energy cost. Above the Coulomb blockade threshold voltage and at high temperature, the charge transport evolves into a sequential tunneling regime between the nearest- nanowires. Our analysis shows that the effective length of the Au-NWs inside the bundle is similar to the 1D localisation length of the electronic wave function （of the order of 120 nm _＋ 20 nm）, but almost two orders of magnitude larger than the diameter of the nanowire. This result confirms the high structural quality of the Au-NW segments.展开更多
High magnetile field spectroscopy has been performed on lead chloride-based perovskite,a material that attracts significant interest for photovoltaic and photonic applications within the past decades.Optical propertie...High magnetile field spectroscopy has been performed on lead chloride-based perovskite,a material that attracts significant interest for photovoltaic and photonic applications within the past decades.Optical properties being mainly driven by the exciton states,we have mcasured the fundamental parameters,such as the exciton binding energy,effective mass,and dielectric constant.Among the inorganic halide perovskites,CsPbCl3 owns the largest exciton binding energy and effective mass.This blue emmitting compound has also been compared with lower band gap energy perovskites and other semiconducting phasces,showing comparable band gap dependences for binding energy and Bohr radius.展开更多
基金supported by the National Science Centre of Poland(NCN)Grants 2016/21/N/ST3/03379,2015/18/E/ST3/00559 and 2019/03/X/ST3/01969the EU Graphene Flagship project(No.785219)+3 种基金by the ATOMOPTO project(TEAM programme of the Foundation for Polish Science cofinanced by the EU within the ERD Fund)funded by the Polish Ministry of Science and Higher Education as part of the“Diamentowy Grant”project for the years 2018-2022support from the Elemental Strategy Initiative conducted by the MEXT,Japan and the CREST(JPMJCR15F3),JSTfunded by the European Regional Development Fund Operational Programme(POIG.02.01.00-14-122/09-00).
文摘In light science and applications,equally important roles are played by efficient light emitters/detectors and by the optical elements responsible for light extraction and delivery.The latter should be simple,cost effective,broadband,versatile and compatible with other components of widely desired micro-optical systems.Ideally,they should also operate without high-numerical-aperture optics.Here,we demonstrate that all these requirements can be met with elliptical microlenses 3D printed on top of light emitters.Importantly,the microlenses we propose readily form the collected light into an ultra-low divergence beam(half-angle divergence below 1°)perfectly suited for ultra-longworking-distance optical measurements(600mm with a 1-inch collection lens),which are not accessible to date with other spectroscopic techniques.Our microlenses can be fabricated on a wide variety of samples,including semiconductor quantum dots and fragile van der Waals heterostructures made of novel two-dimensional materials,such as monolayer and few-layer transition metal dichalcogenides.
文摘We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） nanowires, monitored by the temperature and the bias voltage. At low temperature, in the Coulomb blockade regime, the current flow reveals an original cooperative multi-hopping process between 1D-segments of Au-NWs, minimising the charging energy cost. Above the Coulomb blockade threshold voltage and at high temperature, the charge transport evolves into a sequential tunneling regime between the nearest- nanowires. Our analysis shows that the effective length of the Au-NWs inside the bundle is similar to the 1D localisation length of the electronic wave function （of the order of 120 nm _＋ 20 nm）, but almost two orders of magnitude larger than the diameter of the nanowire. This result confirms the high structural quality of the Au-NW segments.
基金Ministry of Education-Singapore(MOE2018-T2-2-0G8,MOE2018-T3-1-002,RG103/15 and RG113/16)National Science Centre Poland(OPUS 2015/33/B/ST3/01915)Agence Nationale dc la Rechcrche(ANR-18-CE30-0023-01,ANR-1O-LABX-0037-NEXT).
文摘High magnetile field spectroscopy has been performed on lead chloride-based perovskite,a material that attracts significant interest for photovoltaic and photonic applications within the past decades.Optical properties being mainly driven by the exciton states,we have mcasured the fundamental parameters,such as the exciton binding energy,effective mass,and dielectric constant.Among the inorganic halide perovskites,CsPbCl3 owns the largest exciton binding energy and effective mass.This blue emmitting compound has also been compared with lower band gap energy perovskites and other semiconducting phasces,showing comparable band gap dependences for binding energy and Bohr radius.
