41results about How to "High pyroelectric coefficient" patented technology

The invention which relates to an FE-AFE phase change pyroelectric ceramic material belongs to the field of pyroelectric ceramic. The invention discloses the FE-AFE phase change pyroelectric ceramic material, a pyroelectric ceramic element and preparation methods of the material and the element. Chemical components of the ceramic material accord with a general chemical formula of (Pb1-3x / 2Lax)(ZryTizSn1-y-z)O3, wherein x is more than 0 and equal to or less than 0.025, y is from 0.38 to 0.46, and z is from 0.14 to 0.18; and the ceramic material is in a ferroelectric phase at room temperature and can generate an FE-AFE phase change with the temperature change with or without an extra electric field. The pyroelectric ceramic element has a large polarized change with the FE-AFE phase change after being polarized or under the effect of a direct current bias, so a large pyroelectric response is obtained, a pyroelectric coefficient is 2-4 times more than traditional pyroelectric coefficients, and heat stagnation substantially does not exist, so the pyroelectric ceramic element can be used in the uncooled infrared detection technology and the fields of heat-electrical energy transformation and the like.

The invention discloses a composite pyroelectric material and a preparation method thereof as well as a method used in the preparation of a silica-based thick film. The material is a composite material of polyvinylidene fluoride and Pb1+x(Sc0.5Ta0.5)O3 nano ceramic powder, wherein x is more than or equal to 0.05 and less than or equal to 0.1; and the volume percent of the nano ceramic powder is 30 to 70 percent. The preparation method of the composite pyroelectric material and the silica-based thick film thereof comprises the following steps: (1) scandium lead tantanate precursor sol is prepared and scandium lead tantanate nano power is prepared by means of the sol; (2) PVDF solution and scandium lead tantanate PVDF composite slurry are prepared; (3) after the pretreatment of silicone substrate is completed, a thermal insulation layer and a bottom electrode are deposited; (4) the spin coating and the deposition of a composite pyroelectric thick film are completed; and (5) an upper electrode is deposited and polarized. The composite pyroelectric material, which has the advantages of both organic pyroelectric material and inorganic pyroelectric material, has a small dielectric constant, low thermal conductivity and very high voltage response optimal value; meanwhile, because film-forming temperature is extremely low, the material is suitable to be used in semiconductor integration process; moreover, the thickness of the composite pyroelectric thick film can be controlled within 5 micron and 20 micron, which ensures higher film-forming efficiency.

The embodiment of the present invention discloses a method for manufacturing a conductive polymer pyroelectric nano film, which includes: preparing a conductive polymer nanowire film by a template method, then preparing a conductive polymer nanowire film by a LB film method, and finally using a chemical method to prepare a conductive polymer nanowire film. The nanowire film is doped and reduced to obtain a conductive polymer pyroelectric nano film structure. The conductive polymer pyroelectric nano film prepared by the invention has the advantages of high pyroelectric coefficient, low heat conduction and good stability, and has wide application in micro / nano energy collection and energy storage devices.

The invention discloses a method for preparing a porous barium strontium titanate field pyroelectric ceramic, comprising the following steps: firstly, mixing raw materials according to a stoichiometric ratio of respective chemical formula; pre-sintering the mixture at 800-1200 DEG C for 1-6 hours to obtain pre-sintered ceramic powder; then adding an organic substance pore-forming agent, mixing uniformly, tabletting and forming; heating again to remove organic substances; sintering, grinding, cleaning, adding an electrode and sintering the electrode. The porous BST field pyroelectric ceramic of the invention has the advantages of high pyroelectric coefficient, low dielectric loss, proper dielectric constant and excellent comprehensive pyroelectric property, and meets the requirements for manufacturing pyroelectric infrared detectors.

The invention relate to a method for preparing high-performance BST (barium strontium titanate) pyroelectric ceramics by adopting a post-annealing process. According to the method, BST ceramics obtained through sintering is subjected to annealing at the oxygen atmosphere, the annealing temperature ranges from 800 DEG C to 1,250 DEG C, the annealing time ranges from 2 hours to 5 hours, and then the high-performance BST pyroelectric ceramics can be prepared. According to the method for preparing the high-performance BST pyroelectric ceramics by adopting the post-annealing process, the annealing treatment is performed after the BST pyroelectric ceramics is obtained through sintering, and the high-performance BST pyroelectric ceramics can be prepared; the dielectric constant is high and can be higher than 9,500; the pyroelectric coefficient is high and can be higher than 18*10<-8>C / cm<2>K; and further, a sample is high in purity and performance and good in uniformity, manufacturing requirements of an uncooled infrared focal plane device can be met, and the problem that the BST ceramics cannot be sintered to high density is effectively solved.