Colloidal CdSe nanoplatelets are thin semiconductor materials with atomic flatness surfaces and one-dimensional strong quantum confinement,and hence they own very narrow and anisotropic emission.Here,we present a poly...Colloidal CdSe nanoplatelets are thin semiconductor materials with atomic flatness surfaces and one-dimensional strong quantum confinement,and hence they own very narrow and anisotropic emission.Here,we present a polydimethylsiloxane(PDMS)assisted transferring method that can pick up single layer CdSe nanoplatelet films self-assembled on a liquid surface and then precisely transfer to a target.By layer-by-layer picking up and transferring,multiple layers of CdSe films can be built up to form CdSe stacks with each single layer having dominant in-plane transition dipole distribution,which both material and energic structures are analogous to traditional multiple quantum wells grown by molecular-beam epitaxy.Additionally,with the great flexibility of colloidal nanoplatelets and this transferring method,CdSe nanoplatelets films can be combined with other materials to form hybrid heterostructures.We transferred a single-layer CdSe film onto WS_(2) flakes,and precisely studied the fast energy transfer rate with controlled CdSe nanoplatelet orientation and by using a streak camera with a ps time resolution.展开更多
Colloidal II-VI nanoplatelets(NPLs)are solution-processable two-dimensional(2D)quantum dots that have vast potential in highperformance optoelectronic applications,including light-emitting diodes,sensors,and lasers.Su...Colloidal II-VI nanoplatelets(NPLs)are solution-processable two-dimensional(2D)quantum dots that have vast potential in highperformance optoelectronic applications,including light-emitting diodes,sensors,and lasers.Superior properties,such as ultrapure emission,giant oscillator strength transition,and directional dipoles,have been demonstrated in these NPLs,which can improve the efficiency of light-emitting diodes and lower the threshold of lasers.In this review,we present an overview of the current progress and propose perspectives on the most well-studied II-VI NPLs that are suitable for the optoelectronic applications.We emphasize that the control of the symmetrical shell growth of NPLs is critical for the practical utilization of the advantages of NPLs in these devices.展开更多
The on-chip measurement of polarization states plays an increasingly crucial role in modern sensing and imaging applications.While high-performance monolithic linearly polarized photodetectors have been extensively st...The on-chip measurement of polarization states plays an increasingly crucial role in modern sensing and imaging applications.While high-performance monolithic linearly polarized photodetectors have been extensively studied,integrated circularly polarized light(CPL)photodetectors are still hindered by inadequate discrimination capability.This study presents a broadband CPL photodetector utilizing achiral all-dielectric nanostructures,achieving an impressive discrimination ratio of~107 at a wavelength of 405 nm.Our device shows outstanding CPL discrimination capability across the visible band without requiring intensity calibration.It functions based on the CPL-dependent near-field modes within achiral structures:under left or right CPL illumination,distinct near-field modes are excited,resulting in asymmetric irradiation of the two electrodes and generating a photovoltage with directions determined by the chirality of the incident light field.The proposed design strategy facilitates ultra-compact CPL detection across diverse materials,structures,and spectral ranges,presenting a novel avenue for achieving high-performance monolithic CPL detection.展开更多
The quantum Toffoli gate is one of the most important three-qubit gates,but it is challenging to construct a chip according to the complicated traditional circuit.Using the optimized 3D configuration with an overpass ...The quantum Toffoli gate is one of the most important three-qubit gates,but it is challenging to construct a chip according to the complicated traditional circuit.Using the optimized 3D configuration with an overpass waveguide to reduce the circuit complexity,we successfully fabricate an on-chip path encoded photonic quantum Toffoli gate enabled by the 3D capability of the femtosecond laser direct writing(FLDW)for the first time to our knowledge,whose truth-table fidelity is higher than 85.5%.Furthermore,a path encoded four-qubit controlled-controlled-controlled NOT gate is written to confirm the scalability of this resource-saving technique.This work paves the way for the FLDW of more complex and powerful photonic quantum computation chips.展开更多
We report the direct observation of coupling between a single self-assembled InAs quantum dot and a wetting layer, based on strong diamagnetic shifts of many-body exciton states using magneto-photoluminescence spectro...We report the direct observation of coupling between a single self-assembled InAs quantum dot and a wetting layer, based on strong diamagnetic shifts of many-body exciton states using magneto-photoluminescence spectroscopy. An extremely large positive diamagnetic coefficient is observed when an electron in the wetting layer combines with a hole in the quantum dot; the coefficient is nearly one order of magnitude larger than that of the exciton states confined in the quantum dots. Recombination of electrons with holes in a quantum dot of the coupled system leads to an unusual negative diamagnetic effect, which is five times stronger than that in a pure quantum dot system. This effect can be attributed to the expansion of the wavefunction of remaining electrons in the wetting layer or the spread of electrons in the excited states of the quantum dot to the wetting layer after recombination. In this case, the wavefunction extent of the final states in the quantum dot plane is much larger than that of the initial states because of the absence of holes in the quantum dot to attract electrons. The properties of emitted photons that depend on the large electron wavefunction extents in the wetting layer indicate that the coupling occurs between systems of different dimensionality, which is also verified from the results obtained by applying a magnetic field in different configurations. This study paves a new way to observe hybrid states with zero- and two-dimensional structures, which could be useful for investigating the Kondo physics and implementing spin-based solid-state quantum information processing.展开更多
Perovskite-enabled optical devices have drawn intensive interest and have been considered promising candidates for integrated optoelectronic systems.As one of the important photonic functions,optical phase modulation ...Perovskite-enabled optical devices have drawn intensive interest and have been considered promising candidates for integrated optoelectronic systems.As one of the important photonic functions,optical phase modulation previously was demonstrated with perovskite substrate and complex refractive index engineering with laser scribing.Here we report on the new scheme of achieving efficient phase modulation by combining detour phase design with 40 nm ultrathin perovskite films composed of nanosized crystalline particles.Phase modulation was realized by binary amplitude patterning,which significantly simplifies the fabrication process.Perovskite nanocrystal films exhibit significantly weak ion migration effects under femtosecond laser writing,resulting in smooth edges along the laser ablated area and high diffractive optical quality.Fabrication of a detour-phased perovskite ultrathin planar lens with a diameter of 150μm using femtosecond laser scribing was experimentally demonstrated.A high-performance 3D focus was observed,and the fabrication showed a high tolerance with different laser writing powers.Furthermore,the high-quality imaging capability of perovskite ultrathin planar lenses with a suppressed background was also demonstrated.展开更多
Charge carrier dynamics essentially determines the performance of various optoelectronic applications of colloidal semiconductor nanocrystals.Among them,two-dimensional nanoplatelets provide new adjustment freedom for...Charge carrier dynamics essentially determines the performance of various optoelectronic applications of colloidal semiconductor nanocrystals.Among them,two-dimensional nanoplatelets provide new adjustment freedom for their unique core/crown heterostructures.Herein,we demonstrate that by fine-tuning the core size and the lateral quantum confinement,the charge carrier transfer rate from the crown to the core can be varied by one order of magnitude in CdSe/CdSeS core/alloy-crown nanoplatelets.In addition,the transfer can be affected by a carrier blocking mechanism,i.e.,the filled carriers hinder further possible transfer.Furthermore,we found that the biexciton interaction is oppositely affected by quantum confinement and electron delocalization,resulting in a non-monotonic variation of the biexciton binding energy with the emission wavelength.This work provides new observations and insights into the charge carrier transfer dynamics and exciton interactions in colloidal nanoplatelets and will promote their further applications in lasing,display,sensing,etc.展开更多
Two-dimensional(2D)materials are highly sensitive to substrates,interfaces,and the surrounding environments.Suspended 2D materials are free from substrate-induced effects,thus an ideal approach to study their intrinsi...Two-dimensional(2D)materials are highly sensitive to substrates,interfaces,and the surrounding environments.Suspended 2D materials are free from substrate-induced effects,thus an ideal approach to study their intrinsic properties.However,it is very challenging to prepare large-area suspended 2D materials with high efficiency.Here we report a universal method,based on pretreatments of densely patterned hole array substrates with either oxygenplasma or gold film deposition,to prepare large-area suspended mono-and few-layer 2D materials.Multiple structural,optical,and electrical characterization tools were used to fully evaluate the improved performance of various suspended 2D layers.Some of these observations reported in this study are:(1)Observation of a new Raman low frequency mode for the suspended MoS_(2);(2)Significantly stronger photoluminescence(PL)and second harmonic generation(SHG)signals of suspended WSe_(2),which enables the study of new optical transition processes;(3)The low energy electron diffraction pattern on suspended MoS_(2) also exhibits much sharper spots than that on the supported area;and(4)The mobility of suspended graphene device approaches 300000 cm^(2) V^(-1) s^(-1),which is desirable to explore the intrinsic properties of graphene.This work provides an innovative and efficient route for fabricating suspended 2D materials,and we expect that it can be broadly used for studying intrinsic properties of 2D materials and in applications of hybrid active nanophotonic and electronic devices.展开更多
Perovskite light-emitting diodes(PeLEDs)are attracting increasing attention owing to their impressive efficiencies and high luminance across the full visible light range.Further improvement of the external quantum eff...Perovskite light-emitting diodes(PeLEDs)are attracting increasing attention owing to their impressive efficiencies and high luminance across the full visible light range.Further improvement of the external quantum efficiency(EQE)of planar PeLEDs is limited by the light out-coupling efficiency.Introducing perovskite emitters with directional emission in PeLEDs is an effective way to improve light extraction.Here,we report that it is possible to achieve directional emission in mixed-dimensional perovskites by controlling the orientation of the emissive center in the film.Multiple characterization methods suggest that our mixed-dimensional perovskite film shows highly orientated transition dipole moments(TDMs)with the horizontal ratio of over 88%,substantially higher than that of the isotropic emitters.The horizontally dominated TDMs lead to PeLEDs with exceptional high light out-coupling efficiency of over 32%,enabling a high EQE of 18.2%.展开更多
基金supported by Beijing Natural Science Foundation(grant no.Z190005)the National Natural Science Foundation of China(grant nos.61875002)the National Key R&D Program of China(grant no.2018YFA0306302)。
文摘Colloidal CdSe nanoplatelets are thin semiconductor materials with atomic flatness surfaces and one-dimensional strong quantum confinement,and hence they own very narrow and anisotropic emission.Here,we present a polydimethylsiloxane(PDMS)assisted transferring method that can pick up single layer CdSe nanoplatelet films self-assembled on a liquid surface and then precisely transfer to a target.By layer-by-layer picking up and transferring,multiple layers of CdSe films can be built up to form CdSe stacks with each single layer having dominant in-plane transition dipole distribution,which both material and energic structures are analogous to traditional multiple quantum wells grown by molecular-beam epitaxy.Additionally,with the great flexibility of colloidal nanoplatelets and this transferring method,CdSe nanoplatelets films can be combined with other materials to form hybrid heterostructures.We transferred a single-layer CdSe film onto WS_(2) flakes,and precisely studied the fast energy transfer rate with controlled CdSe nanoplatelet orientation and by using a streak camera with a ps time resolution.
基金supported by the National Natural Science Foundation of China(Nos.62375004 and 61875002)China Postdoctoral Science Foundation(Nos.2023M731476,2023T160286 and 2024M751274)Beijing Postdoctoral Research Foundation.
文摘Colloidal II-VI nanoplatelets(NPLs)are solution-processable two-dimensional(2D)quantum dots that have vast potential in highperformance optoelectronic applications,including light-emitting diodes,sensors,and lasers.Superior properties,such as ultrapure emission,giant oscillator strength transition,and directional dipoles,have been demonstrated in these NPLs,which can improve the efficiency of light-emitting diodes and lower the threshold of lasers.In this review,we present an overview of the current progress and propose perspectives on the most well-studied II-VI NPLs that are suitable for the optoelectronic applications.We emphasize that the control of the symmetrical shell growth of NPLs is critical for the practical utilization of the advantages of NPLs in these devices.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030009)the National Key Research and Development Program of China(Grant No.2022YFA1604304)the National Natural Science Foundation of China(Grant No.92250305).
文摘The on-chip measurement of polarization states plays an increasingly crucial role in modern sensing and imaging applications.While high-performance monolithic linearly polarized photodetectors have been extensively studied,integrated circularly polarized light(CPL)photodetectors are still hindered by inadequate discrimination capability.This study presents a broadband CPL photodetector utilizing achiral all-dielectric nanostructures,achieving an impressive discrimination ratio of~107 at a wavelength of 405 nm.Our device shows outstanding CPL discrimination capability across the visible band without requiring intensity calibration.It functions based on the CPL-dependent near-field modes within achiral structures:under left or right CPL illumination,distinct near-field modes are excited,resulting in asymmetric irradiation of the two electrodes and generating a photovoltage with directions determined by the chirality of the incident light field.The proposed design strategy facilitates ultra-compact CPL detection across diverse materials,structures,and spectral ranges,presenting a novel avenue for achieving high-performance monolithic CPL detection.
基金National Key Research and Development Program of China(2018YFB1107205,2016YFA0301302)National Natural Science Foundation of China(12134001,61590933,61590932,11527901,11774333,62061160487)+2 种基金Joint Fund for Equipment Pre-research Space Science and Technology(6141B06140601)Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB24030601)Fundamental Research Funds for the Central Universities。
文摘The quantum Toffoli gate is one of the most important three-qubit gates,but it is challenging to construct a chip according to the complicated traditional circuit.Using the optimized 3D configuration with an overpass waveguide to reduce the circuit complexity,we successfully fabricate an on-chip path encoded photonic quantum Toffoli gate enabled by the 3D capability of the femtosecond laser direct writing(FLDW)for the first time to our knowledge,whose truth-table fidelity is higher than 85.5%.Furthermore,a path encoded four-qubit controlled-controlled-controlled NOT gate is written to confirm the scalability of this resource-saving technique.This work paves the way for the FLDW of more complex and powerful photonic quantum computation chips.
基金This work was supported by the National Basic Research Program of China （Nos. 2013CB328706 and 2014CB921003）, the National Natural Science Foundation of China （Nos. 91436101, 11174356, and 61275060）, the Strategic Priority Research Program of the Chinese Academy of Sciences （No. XDB07030200）, and the 100 Talents Program of Chinese Academy of Sciences. We thank Jean-Pierre Leburton for helpful discussions.
文摘We report the direct observation of coupling between a single self-assembled InAs quantum dot and a wetting layer, based on strong diamagnetic shifts of many-body exciton states using magneto-photoluminescence spectroscopy. An extremely large positive diamagnetic coefficient is observed when an electron in the wetting layer combines with a hole in the quantum dot; the coefficient is nearly one order of magnitude larger than that of the exciton states confined in the quantum dots. Recombination of electrons with holes in a quantum dot of the coupled system leads to an unusual negative diamagnetic effect, which is five times stronger than that in a pure quantum dot system. This effect can be attributed to the expansion of the wavefunction of remaining electrons in the wetting layer or the spread of electrons in the excited states of the quantum dot to the wetting layer after recombination. In this case, the wavefunction extent of the final states in the quantum dot plane is much larger than that of the initial states because of the absence of holes in the quantum dot to attract electrons. The properties of emitted photons that depend on the large electron wavefunction extents in the wetting layer indicate that the coupling occurs between systems of different dimensionality, which is also verified from the results obtained by applying a magnetic field in different configurations. This study paves a new way to observe hybrid states with zero- and two-dimensional structures, which could be useful for investigating the Kondo physics and implementing spin-based solid-state quantum information processing.
基金Guangdong Major Project of Basic and Applied Basic Research(2020B0301030009)National Natural Science Foundation of China(12004012,12004013,12041602,91750203,91850111,92150301)+1 种基金China Postdoctoral Science Foundation(2020M680220,2020M680230)National Key Research and Development Program of China(2018YFA0306302)。
文摘Perovskite-enabled optical devices have drawn intensive interest and have been considered promising candidates for integrated optoelectronic systems.As one of the important photonic functions,optical phase modulation previously was demonstrated with perovskite substrate and complex refractive index engineering with laser scribing.Here we report on the new scheme of achieving efficient phase modulation by combining detour phase design with 40 nm ultrathin perovskite films composed of nanosized crystalline particles.Phase modulation was realized by binary amplitude patterning,which significantly simplifies the fabrication process.Perovskite nanocrystal films exhibit significantly weak ion migration effects under femtosecond laser writing,resulting in smooth edges along the laser ablated area and high diffractive optical quality.Fabrication of a detour-phased perovskite ultrathin planar lens with a diameter of 150μm using femtosecond laser scribing was experimentally demonstrated.A high-performance 3D focus was observed,and the fabrication showed a high tolerance with different laser writing powers.Furthermore,the high-quality imaging capability of perovskite ultrathin planar lenses with a suppressed background was also demonstrated.
基金This work was supported by the National Natural Science Foundation of China(No.61875002)the National Key R&D Program of China(No.2018YFA0306302)+4 种基金the Beijing Natural Science Foundation(No.Z190005)the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices(No.KF202208)The author acknowledges the support of the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)the National Natural Science Foundation of China(Nos.11874130 and 22073022)the support from the DNL Cooperation Fund,CAS(No.DNL202016)of Dalian National Laboratory for Clean Energy。
文摘Charge carrier dynamics essentially determines the performance of various optoelectronic applications of colloidal semiconductor nanocrystals.Among them,two-dimensional nanoplatelets provide new adjustment freedom for their unique core/crown heterostructures.Herein,we demonstrate that by fine-tuning the core size and the lateral quantum confinement,the charge carrier transfer rate from the crown to the core can be varied by one order of magnitude in CdSe/CdSeS core/alloy-crown nanoplatelets.In addition,the transfer can be affected by a carrier blocking mechanism,i.e.,the filled carriers hinder further possible transfer.Furthermore,we found that the biexciton interaction is oppositely affected by quantum confinement and electron delocalization,resulting in a non-monotonic variation of the biexciton binding energy with the emission wavelength.This work provides new observations and insights into the charge carrier transfer dynamics and exciton interactions in colloidal nanoplatelets and will promote their further applications in lasing,display,sensing,etc.
基金National Key Research and Development Program of China,Grant/Award Numbers:2019YFA0308000,2018YFA0306302,2018YFA0305800,2018YFA0704201Youth Innovation Promotion Association of CAS,Grant/Award Numbers:2019007,2018013+5 种基金National Natural Science Foundation of China,Grant/Award Numbers:62022089,11874405,61725107,61971035,61725107,92163206,51772145National Basic Research Program of China,Grant/Award Number:2015CB921300Strategic Priority Research Program(B)of the Chinese Academy of Sciences,Grant/Award Numbers:XDB07020300,XDB30000000Research Program of Beijing Academy of Quantum Information Sciences,Grant/Award Number:Y18G06Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20180003333 high level talent training project of JiangSu and JiangHai talent program of NanTong。
文摘Two-dimensional(2D)materials are highly sensitive to substrates,interfaces,and the surrounding environments.Suspended 2D materials are free from substrate-induced effects,thus an ideal approach to study their intrinsic properties.However,it is very challenging to prepare large-area suspended 2D materials with high efficiency.Here we report a universal method,based on pretreatments of densely patterned hole array substrates with either oxygenplasma or gold film deposition,to prepare large-area suspended mono-and few-layer 2D materials.Multiple structural,optical,and electrical characterization tools were used to fully evaluate the improved performance of various suspended 2D layers.Some of these observations reported in this study are:(1)Observation of a new Raman low frequency mode for the suspended MoS_(2);(2)Significantly stronger photoluminescence(PL)and second harmonic generation(SHG)signals of suspended WSe_(2),which enables the study of new optical transition processes;(3)The low energy electron diffraction pattern on suspended MoS_(2) also exhibits much sharper spots than that on the supported area;and(4)The mobility of suspended graphene device approaches 300000 cm^(2) V^(-1) s^(-1),which is desirable to explore the intrinsic properties of graphene.This work provides an innovative and efficient route for fabricating suspended 2D materials,and we expect that it can be broadly used for studying intrinsic properties of 2D materials and in applications of hybrid active nanophotonic and electronic devices.
基金the Natural Science Foundation of China(52072337 and 51911530155)the Key Research and Development Program of Zhejiang Province(2021C01030)+1 种基金the China National Postdoctoral Program for Innovative Talents(BX20200288)the China Postdoctoral Science Foundation(2021M70278).
文摘Perovskite light-emitting diodes(PeLEDs)are attracting increasing attention owing to their impressive efficiencies and high luminance across the full visible light range.Further improvement of the external quantum efficiency(EQE)of planar PeLEDs is limited by the light out-coupling efficiency.Introducing perovskite emitters with directional emission in PeLEDs is an effective way to improve light extraction.Here,we report that it is possible to achieve directional emission in mixed-dimensional perovskites by controlling the orientation of the emissive center in the film.Multiple characterization methods suggest that our mixed-dimensional perovskite film shows highly orientated transition dipole moments(TDMs)with the horizontal ratio of over 88%,substantially higher than that of the isotropic emitters.The horizontally dominated TDMs lead to PeLEDs with exceptional high light out-coupling efficiency of over 32%,enabling a high EQE of 18.2%.
