Layer-by-layer polyelectrolyte self-assembly, a common method for preparing high-quality ultra-thin films, was employed to direct the self-assembly behavior of polystyrene-block-poly(methyl methacrylate)(PS-b-PMMA) bl...Layer-by-layer polyelectrolyte self-assembly, a common method for preparing high-quality ultra-thin films, was employed to direct the self-assembly behavior of polystyrene-block-poly(methyl methacrylate)(PS-b-PMMA) block copolymer for the first time. Differing from the previous neutral polymer brushes anchored to silicon substrates via chemical modification, polyelectrolyte multilayers(PEMs) were anchored by electrostatic interaction and provided a stable, smooth, and neutral interface. In the present study, PS-b-PMMA was deposited on poly(acrylamide hydrochloride)/poly(acrylic acid)(PAH/PAA) PEMs prepared by layer-by-layer self-assembly to successfully yield vertical nanodomains after thermal annealing. Seven layered PEMs revealed an excellent, smooth surface, with a low roughness of 0.6 nm. The periodic structure with interlamellar spacing of 47 nm was determined by grazing-incidence small-angle X-ray scattering(GISAXS). The morphology of the PS-b-PMMA nanodomains depended on the polyanion-to-polycation concentration ratio, which is related to the interaction between the block copolymer and the substrate. Our results demonstrate that layer-by-layer self-assembly is a helpful method for the phase separation of block polymers and the fabrication of vertical, ordered nanodomains.展开更多
PbS colloidal quantum dots(QDs)show great promise for short-wave infrared(SWIR)photodetection due to their tunable photoresponse and cost-effective solution processability,positioning them as a strong competitor to In...PbS colloidal quantum dots(QDs)show great promise for short-wave infrared(SWIR)photodetection due to their tunable photoresponse and cost-effective solution processability,positioning them as a strong competitor to InGaAs technologies.Inverted device architectures,essential for compatibility with complementary metal-oxide-semiconductor(CMOS)readout circuits,face performance challenges due to limitations in the hole transport layer(HTL),such as porous NiO_(x)structures that cause surface recombination at low annealing temperatures.To overcome these challenges,herein,we develop a multi-HTL strategy integrating NiO_(x),1,2-ethanedithiol(EDT)-treated PbS,and self-assembled monolayers(SAMs)including[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz)and[2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid(MeO-2PACz),significantly boosting the performance of inverted PbS QD photodetectors,with full-fullerene-based electron transport layers(ETLs).We confirm that the SAMs can effectively block electron transfer and passivate surface defects between the HTL and active layer,with 2PACz achieving an external quantum efficiency of 53%at 1200 nm and MeO-2PACz reducing dark current to 220 nA/cm^(2),yielding a specific detectivity of 1.64×10^(12)Jones,which represents the highest reported value under similar testing conditions and in this spectral region.This multi-HTL strategy enables high-performance SWIR imaging compatible with CMOS and thin-film transistor(TFT)circuits,advancing QD-based photodetection technologies.展开更多
The fabrication of bit-patterned media （BPM） is crucial for new types of hard disk drives. The development of methods for the production of BPM is progressing rapidly. Conventional lithography reaches the limit rega...The fabrication of bit-patterned media （BPM） is crucial for new types of hard disk drives. The development of methods for the production of BPM is progressing rapidly. Conventional lithography reaches the limit regarding lateral resolution, and new routes are needed. In this study, we mainly focus on the dependence of the size and shape of magnetic nanodots on the Ar＋-ion etching duration, using silica dots as masks. Two-dimensional （2D） arrays of magnetic nanostructures are created using silica-filled diblock-copolymer micelles as templates. After the self-assembly of the micelles into 2D hexagonal arrays, the polymer shell is removed, and the SiO2 cores are utilized to transform the morphology into a （Co/Pt）2-multilayer via ion etching under normal incidence. The number of preparation steps is kept as low as possible to simplify the formation of the nanostructure arrays. High-resolution in situ grazing-incidence small-angle X-ray scattering （GISAXS） investigations are performed during the Ar＋-ion etching to monitor and control the fabrication process. The in situ investigation provides information on how the etching conditions can be improved for further ex situ experiments. The GISAXS patterns are compared with simulations. We observe that the dots change in shape from cylindrical to conical during the etching process. The magnetic behavior is studied by utilizing the magneto-optic Kerr effect. The Co/Pt dots exhibit different magnetic behaviors depending on their size, interparticle distance, and etching time. They show ferromagnetism with an easy axis of magnetization perpendicular to the film. A systematic dependence of the coercivitv on the dot size is observed.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 11605149, 11405259, U1932118, and U1732123)the Natural Science Foundation of Hunan Province (No. 2017JJ3309)+3 种基金the China Postdoctoral Science Foundation (No. 2017 M622595)the Zhejiang Public Service Technology Research Program/Analytical Test (No. LGC19F040001)the National Key R&D Program of China (No. 2017YFA0403000)the Science and Technology Commission of Shanghai Municipality (No. 17JC1400802)
文摘Layer-by-layer polyelectrolyte self-assembly, a common method for preparing high-quality ultra-thin films, was employed to direct the self-assembly behavior of polystyrene-block-poly(methyl methacrylate)(PS-b-PMMA) block copolymer for the first time. Differing from the previous neutral polymer brushes anchored to silicon substrates via chemical modification, polyelectrolyte multilayers(PEMs) were anchored by electrostatic interaction and provided a stable, smooth, and neutral interface. In the present study, PS-b-PMMA was deposited on poly(acrylamide hydrochloride)/poly(acrylic acid)(PAH/PAA) PEMs prepared by layer-by-layer self-assembly to successfully yield vertical nanodomains after thermal annealing. Seven layered PEMs revealed an excellent, smooth surface, with a low roughness of 0.6 nm. The periodic structure with interlamellar spacing of 47 nm was determined by grazing-incidence small-angle X-ray scattering(GISAXS). The morphology of the PS-b-PMMA nanodomains depended on the polyanion-to-polycation concentration ratio, which is related to the interaction between the block copolymer and the substrate. Our results demonstrate that layer-by-layer self-assembly is a helpful method for the phase separation of block polymers and the fabrication of vertical, ordered nanodomains.
基金supported by National Natural Science Foundation of China(No.12204318)Shenzhen Science and Technology Program(Nos.RCYX20221008092908030 and JCYJ20241202124709012)Natural Science Foundation of Top Talent of SZTU(Nos.GDRC202340 and GDRC202345).
文摘PbS colloidal quantum dots(QDs)show great promise for short-wave infrared(SWIR)photodetection due to their tunable photoresponse and cost-effective solution processability,positioning them as a strong competitor to InGaAs technologies.Inverted device architectures,essential for compatibility with complementary metal-oxide-semiconductor(CMOS)readout circuits,face performance challenges due to limitations in the hole transport layer(HTL),such as porous NiO_(x)structures that cause surface recombination at low annealing temperatures.To overcome these challenges,herein,we develop a multi-HTL strategy integrating NiO_(x),1,2-ethanedithiol(EDT)-treated PbS,and self-assembled monolayers(SAMs)including[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz)and[2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid(MeO-2PACz),significantly boosting the performance of inverted PbS QD photodetectors,with full-fullerene-based electron transport layers(ETLs).We confirm that the SAMs can effectively block electron transfer and passivate surface defects between the HTL and active layer,with 2PACz achieving an external quantum efficiency of 53%at 1200 nm and MeO-2PACz reducing dark current to 220 nA/cm^(2),yielding a specific detectivity of 1.64×10^(12)Jones,which represents the highest reported value under similar testing conditions and in this spectral region.This multi-HTL strategy enables high-performance SWIR imaging compatible with CMOS and thin-film transistor(TFT)circuits,advancing QD-based photodetection technologies.
文摘The fabrication of bit-patterned media （BPM） is crucial for new types of hard disk drives. The development of methods for the production of BPM is progressing rapidly. Conventional lithography reaches the limit regarding lateral resolution, and new routes are needed. In this study, we mainly focus on the dependence of the size and shape of magnetic nanodots on the Ar＋-ion etching duration, using silica dots as masks. Two-dimensional （2D） arrays of magnetic nanostructures are created using silica-filled diblock-copolymer micelles as templates. After the self-assembly of the micelles into 2D hexagonal arrays, the polymer shell is removed, and the SiO2 cores are utilized to transform the morphology into a （Co/Pt）2-multilayer via ion etching under normal incidence. The number of preparation steps is kept as low as possible to simplify the formation of the nanostructure arrays. High-resolution in situ grazing-incidence small-angle X-ray scattering （GISAXS） investigations are performed during the Ar＋-ion etching to monitor and control the fabrication process. The in situ investigation provides information on how the etching conditions can be improved for further ex situ experiments. The GISAXS patterns are compared with simulations. We observe that the dots change in shape from cylindrical to conical during the etching process. The magnetic behavior is studied by utilizing the magneto-optic Kerr effect. The Co/Pt dots exhibit different magnetic behaviors depending on their size, interparticle distance, and etching time. They show ferromagnetism with an easy axis of magnetization perpendicular to the film. A systematic dependence of the coercivitv on the dot size is observed.
