61results about How to "Adjustable bandgap" patented technology

The invention relates to the field of controlled preparation of semi-conductivity single-walled carbon nanotubes, in particular to a method for preparing a narrow-band-gap-distribution high-purity semi-conductivity single-walled carbon nanotube through a partial-carbon-coated metal catalyst. By means of a segmented copolymer self-assembly method, a uniform-size copolymer thin film coated metal anion nanometer cluster is prepared; single-dispersion partial-carbon-coated metal catalyst nanoparticles are obtained by controlling the annealing, oxidizing and reducing conditions of solvents; nitrogen serves as in-situ etching gas, and the narrow-band-gap-distribution high-purity semi-conductivity single-walled carbon nanotube directly grows. The content of the semi-conductivity single-walled carbon nanotube is larger than 98%, and the band gap difference is 0.05 eV at least and can be adjusted. The direct controllable growth of the narrow-band-gap-distribution high-purity semi-conductivity single-walled carbon nanotube is achieved, the bottleneck of control and preparation of the narrow-band-gap-distribution high-purity semi-conductivity single-walled carbon nanotube at the present stage is broken through, and it is proved that the nanotube is an ideal tunnel material for establishing a thin film field effect transistor.

The invention provides a black-phosphorus quantum-dot photocatalyst with adjustable band gaps, a preparation method and application thereof. The black-phosphorus quantum-dot photocatalyst is prepared by a simple heating reaction method, the sizes and the band gaps of black-phosphorus quantum dots are regulated and controlled by changing a reaction solvent, and further the photocatalytic property of the black-phosphorus quantum-dot photocatalyst is enhanced. The researched black-phosphorus quantum dots can be effectively applied in organic pollutants such as photocatalytic-degradation rhodamine B and the like. The black-phosphorus quantum-dot photocatalyst has the advantages of no pollution, low cost, stability and simple preparation process and the like.

The invention discloses a preparation method of a large-sized mixed halogen methylamine lead-bromine-chlorine crystal. The preparation method comprises the following steps: step S1, stirring a monomethylamine water solution and a hydrobromic acid water solution, and drying by distillation; step S2, stirring a monomethylamine water solution and hydrochloric acid, and drying by distillation; step S3, dissolving PbBr2 with CH3NH3Br and dissolving PbCl2 with CH3NH3Cl into DMF and DMSO solvents to obtain a CH3NH3Pb(Br1-xClx)3 mother liquor; and changing the molar ratio of PbBr2 to PbCl2 to obtain CH3NH3Pb(Br1-xClx)3 mother liquor with different x values; and step S4, raising the temperature of the CH3NH3Pb(Br1-xClx)3 mother liquor to be 95 to 105 DEG C, maintaining a constant temperature until the crystal is separated out, and taking out the crystal when the size of the crystal is not increased any longer. The CH3NH3Pb(Br1-xClx)3 crystal with different halogen proportions can be obtained by changing the proportion of raw materials.