53 results about "Exciton binding energy" patented technology

Provided is a light emitting device formed of an indirect transition semiconductor configured from a semiconductor material having high exciton binding energy, wherein an active layer of the indirect transition semiconductor or an active region by a pn junction is formed, the light emitting device has an electrode for injecting current into the active layer or the active region, and the internal quantum efficiency is 10% or more.

The present invention provides a preparing method of ZnO quantum dot. Firstly, processing surface treatment to a substrate, then forming a layer nano-sphere assembled by itself by czochralski method in deionized water, the nano-sphere is used as a template for preparing ZnO quantum dot; further, depositing a layer ZnO film which thickness is 5nm-50nm by electron beam evaporation under the conditions of temperature between 25-100 DEG C, 10<-4>-10<-6> Torr vacuum; finally, dipping in toluol, and vibrating 2-5 min by ultrasonic to remove the nano-sphere in the template. The ZnO quantum dot prepared by the method has large growth area, regular arrangement, even distribution. The preparing method simply, economically and effectively produces ZnO quantum dot having larger range, and order. The ZnO oxide semiconductor energy gap is wide, direct wide band gap is transmitted, and exciton binding energy is large, the ZnO quantum dot material becomes expectations of high quantum dot laser and nan0-laser by adding the quantum confinement effect of the quantum dot.

Provided are an organic-inorganic-hybrid perovskite nanocrystal particle light-emitter having a two-dimensional structure, a method for producing the same, and a light emitting device using the same. The organic-inorganic-hybrid perovskite nanocrystal particle light-emitter having a two-dimensional structure comprises an organic-inorganic-hybrid perovskite nanocrystal structure having a two-dimensional structure which can be dispersed in an organic solvent. Accordingly, the nanocrystal particle light-emitter comprises an organic-inorganic-hybrid perovskite nanocrystal having a crystal structure combining FCC and BCC; forms a lamellar structure where organic planes and inorganic planes are accumulated in an alternating manner; and can exhibit high color purity by confining excitons in the inorganic planes. In addition, since the exciton diffusion distance decreases and exciton binding energy increases, it is possible to prevent exciton annihilation caused by thermal ionization and delocalization of charge carriers, such that the nanocrystal particle light-emitter can have high luminescence efficiency at room temperature.

The invention belongs to the technical field of photoelectric devices, and discloses a blue light perovskite light emitting diode and a preparation method thereof. A blue light emitting layer of the blue light perovskite light emitting diode comprises perovskite, doped alkali metal halides and large-group organic halides, and the large-group organic halide is organic amine chloride LCl or organicamine bromide LBr, wherein L is a positive monovalent organic amine ion of which the ion radius is greater than 300 picometers. According to the invention, the phase distribution of the blue light perovskite is regulated and controlled through the combined action of the large-group organic halide and the alkali metal halide, the formation of a two-dimensional perovskite phase with low exciton binding energy is reduced, and the formation of other low-dimensional perovskite phases with high exciton binding energy is improved, so that the exciton energy loss caused by a strong exciton-phonon coupling effect is inhibited, and the light emitting efficiency of the blue-light perovskite light emitting diode is improved.

The invention relates to a preparation method and application of solution-processable organic photovoltaic compound with thiophthene (benzoselenophene selenonaphthene) and thiophene (selenophene) as pi-bridge. The structural formula of the compound is shown as the formula I. According to the compound, on the basis of the pi-bridge, appropriate D and A units are selected, and the organic photoelectric compound has low exciton binding energy and can effectively reduce the highest occupied electron orbit energy level of the molecule, which makes it possible that a high-efficiency material acquires high open circuit voltage. The compound is used as the donor material of the active layer of an organic solar battery, and the highest open circuit voltage is higher than 1 V. A fluorinated receptorunit is used as an end group, the compound is not subjected to any additive treatment or thermal and solvent annealing treatment, the battery energy conversion efficiency of the forward structure ismore than 10%, the battery energy conversion efficiency of the reverse element structure reaches 11.5%, and the compound has significant application value.

The invention belongs to the technical field of light-emitting diodes, and discloses a blue-light perovskite thin film, preparation thereof and an inverted quasi-two-dimensional blue-light perovskite light-emitting diode. The method comprises the following steps of: 1) preparing lead bromide, large-group organic halide and cesium bromide into a perovskite precursor solution by adopting an organic solvent; and 2) spin-coating the precursor solution, dropwise adding an anti-solvent in the spin-coating process, and removing the solvent to obtain the blue-light perovskite thin film. The inverted quasi-two-dimensional blue-light perovskite light-emitting diode comprises a cathode, an electron transport layer, an interface layer, a light-emitting layer, a hole transport layer, a hole injection layer and an anode distributed from bottom to top sequentially, wherein the light-emitting layer is the blue-light perovskite thin film. According to the method, the exciton binding energy of the blue-light perovskite can be increased, the morphology of the thin film is improved, meanwhile, formation of a low-dimensional phase (n = 1) is inhibited, and the luminous efficiency of the quasi-two-dimensional blue-light perovskite is improved. The blue light perovskite thin film is used for a light emitting diode, and therefor, blue light emission is achieved, and the light emitting efficiency is improved.

The invention discloses a ZnO-based nanorod / quantum well composite ultraviolet light-emitting diode and a preparation method thereof. The light-emitting diode comprises a substrate. The substrate is provided with an n-type ZnO thin film layer, a ZnO nanorod array, a ZnO / Zn1-xMgxO quantum well active layer, a p-type NiO thin film layer and a first electrode from the bottom up in sequence. A second electrode and the ZnO nanorod array are arranged on the n-type ZnO thin film layer in parallel; and the ZnO / Zn1-xMgxO quantum well active layer covers the ZnO nanorod array, 0.1<=x<=0.3. The light-emitting diode electroluminescent peak wavelength is around 374 nm, and full width at half maximum of the photoluminescence peak is around 17 nm; the light-emitting diode structure can give full play to the advantages of direct broadband gap and high exciton binding energy of the ZnO material and the like, so that polarization effect is reduced effectively, material and interface quality can be improved, effective area of the active layer is increased, light extraction efficiency is improved and spectrum monochromaticity is improved; and besides, low-temperature preparation can be realized, cost is low and industrialization can be realized easily.

The invention provides a method for growing monocrystals, and especially relates to a method for growing red-light octagonal leadless two-dimensional perovskite monocrystals. The monocrystals are (CH3NH3)2MnCl4 concretely, and the method for growing the red-light octagonal leadless two-dimensional perovskite monocrystals is a double-crystallization transformation technology. The double-crystallization transformation technolog comprises the following two steps: A) manganese chloride (MnCl2), methylamine chloride (CH3NH3Cl) and a solution system composed of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) in proportion is slowly crystallized to obtain square red-light (CH3NH3)2MnCl4 leadless two-dimensional perovskite monocrystals; and B) the square red-light leadless two-dimensional perovskite monocrystals obtained in step A) are placed in a hydrochloric acid solution with a concentration of 36-38%, and the obtained solution is slowly crystallized to obtain the octagonal (CH3NH3)2MnCl4 leadless two-dimensional perovskite monocrystals. The (CH3NH3)2MnCl4 leadless two-dimensional perovskite monocrystals have the advantages of great exciton binding energy, good luminescence property and high stability, and especially are of great significance to develop luminescent materials and apply the materials in LEDs.

The invention discloses a p-type conjugated polymer containing 3,4-dicyanothiophene, and a preparation method and an application thereof. The method comprises the following steps: mixing a thiophene unit monomer containing 3,4-dicyanothiophene, a monomer containing a conjugated unit Ar1 and a monomer containing a conjugated unit Ar2, then performing polymerization reaction under catalysis of a catalyst, and purifying the obtained reaction product to obtain the p-type conjugated polymer containing 3,4-dicyanothiophene. The polymer provided by the invention is simple to synthesize, the introduction of a cyano group can regulate the energy level of the molecule, and the cyano group has a low molecular orbital energy level and a wide optical band gap, and can achieve good optical absorption complementation with an n-type organic semiconductor material; and compared with conjugated polymers free from the cyano substituent, the conjugated polymer containing 3,4-dicyanothiophene has the advantages of large dipole moment, high dielectric constant, facilitation of the reduction of exciton binding energy, promotion of the separation of electrons and holes, and realization of the preparationof high-performance organic solar cells.

The invention belongs to the technical field of detectors. The invention provides an optical detector based on surface plasmon polariton electrical modulation transition metal sulfide exciton bindingenergy, a preparation method and application thereof. The method comprises the following steps of: evaporating a gold nano disc array serving as a plasmon array into a channel of a two-dimensional molybdenum disulfide optical detector; and achieving dynamic regulation and control of interaction between molybdenum disulfide excitons and plasmon under different back gate voltages, so that the problem of low quantum efficiency of a two-dimensional semiconductor is overcome, and the problem of low light absorption and luminous efficiency of a two-dimensional optical detector is improved.

The invention discloses a bromine inorganic salt perovskite thin film and a preparation method thereof. The molecular formula of the bromine inorganic salt perovskite thin film is [PbBr2-MBr-CsBr-MBr]n-PbBr2, wherein the MBr is NaBr, LiBr or KBr, and the LiBr is NaBr, LiBr or KBr; n is 1 to 10; the preparation method comprises the following steps: putting a base material to be deposited into a vacuum sealed chamber; evaporating sources of PbBr2, CsBr and MBr are started in sequence and deposited on the base material in a layered mode to form a [PbBr2-MBr-CsBr-MBr] perovskite layer, cyclic deposition is conducted for a plurality of periods, a single layer of PbBr2 is deposited on the uppermost layer, annealing treatment is conducted, and the bromine inorganic salt perovskite thin film is formed. The bromine inorganic salt perovskite thin film provided by the invention has good conductivity; the perovskite light-emitting diode with the bromine inorganic salt perovskite thin film as thelight-emitting layer has the characteristics of high carrier mobility, high exciton binding energy, high light-emitting efficiency, high element abundance, low cost and the like.

The invention discloses a perovskite thin film and a preparation method and application thereof. The preparation method of the perovskite thin film comprises the following steps of 1) mixing CsI, CsBrand PbI2 to prepare a perovskite precursor solution, 2) preparing an ethyl ammonium iodide solution, and 3) mixing the perovskite precursor solution and the ethyl ammonium iodide solution, forming afilm, and annealing to obtain the perovskite thin film. Ethyl ammonium iodide is added into the perovskite precursor solution, then film forming is performed, inorganic perovskite crystals with very small particle sizes can be formed under the passivation effect of the ethyl ammonium iodide, and then the perovskite thin film with low defect state density, small grain size and high exciton bindingenergy is prepared.

The invention relates to the field of covalent organic framework materials and photocatalytic organic reactions, in particular to a COF material for improving photo-generated charge separation and a preparation method and application of the COF material. According to the present invention, 1, 3, 5-tri (4-aminophenyl) benzene (TAPB) is adopted as a donor unit, and a novel D-A type multi-bibenzothiadiazole TPAB-DTT-COF covalent organic framework material using a conjugated unit 2, 1, 3-benzothiadiazole as an acceptor unit is prepared; tAPB is an excellent electron donor unit which is widely used at present, polybiphenyl thiadiazolyl is an electron withdrawing group, the combination and matching of TAPB and polybiphenyl thiadiazolyl enhance the electronegativity difference value in molecules, reduce the exciton binding energy, promote the transfer of electrons from TAPB to a DTT unit, enhance the in-plane transmission and exciton separation efficiency, dissociate excitons under illumination, and improve the efficiency of electron transfer. The TAPB-DTT-COF material has the advantages that the TAPB-DTT-COF material has obvious photocurrent response signal, more obvious charge transfer performance and good photocatalytic performance;

The invention relates to a two-dimensional perovskite material and a preparation method thereof, the molecular formula of the two-dimensional perovskite material is RAN-1BnX3n + 1, n = 1-4; wherein A is an organic cation, B is a metal cation, X is a halogen anion, the structural formula of R is as shown in the following formula (1), and R1 is a straight-chain or branched-chain alkyl group with the carbon atom number of 2-20; according to the two-dimensional perovskite material, a quantum well structure can be eliminated, the exciton binding energy is low, and the carrier transmission performance is high; the preparation method of the two-dimensional perovskite material is simple and controllable in preparation condition and suitable for industrial production. The invention further provides a solar cell, the material of a light absorption layer of the solar cell comprises the two-dimensional perovskite material, and the solar cell has high and stable photoelectric conversion efficiency.

The invention discloses a preparation method for a high-transmittance diffuser plate and belongs to the technical field of diffuser plate preparation. In the invention, polyvinylpyrrolidone powder isdissolved in a light-transmitting solution and the nucleation rate thereof is increased during the process of generating stannic oxide grains by oxidizing stannous mono-sulphate; a transparent homogeneous sol in the invention contains zinc oxide and is doped with aluminum nitrate nonahydrate; band gap and exciton binding energy of zinc oxide are higher; a polyamide acid sol is prepared by taking 4,4'-diaminodiphenyl ether and pyromellitic dianhydride as raw materials; a hybrid membrane at molecular level is acquired under the cross-linking effect of the polyamide acid sol and the transparent adhesive solution through hydrogen bonds; superfine indium tin oxide powder is adopted for reducing an inductive dipole moment, reducing the diffusing in the diffuser plate and increasing the light diffusion rate; the compound of the superfine indium tin oxide powder and the transparent homogeneous sol can increase the stability of the adhesive solution, can narrow the size distribution of nano-particles in the hybrid membrane and can increase the light transmissivity of the diffuser plate; the high-transmittance diffuser plate has a wide application prospect.

The invention discloses a ZnO-based nanorod / quantum well composite ultraviolet light-emitting diode and a preparation method thereof. The light-emitting diode comprises a substrate. The substrate is provided with an n-type ZnO thin film layer, a ZnO nanorod array, a ZnO / Zn1-xMgxO quantum well active layer, a p-type NiO thin film layer and a first electrode from the bottom up in sequence. A second electrode and the ZnO nanorod array are arranged on the n-type ZnO thin film layer in parallel; and the ZnO / Zn1-xMgxO quantum well active layer covers the ZnO nanorod array, 0.1<=x<=0.3. The light-emitting diode electroluminescent peak wavelength is around 374 nm, and full width at half maximum of the photoluminescence peak is around 17 nm; the light-emitting diode structure can give full play to the advantages of direct broadband gap and high exciton binding energy of the ZnO material and the like, so that polarization effect is reduced effectively, material and interface quality can be improved, effective area of the active layer is increased, light extraction efficiency is improved and spectrum monochromaticity is improved; and besides, low-temperature preparation can be realized, cost is low and industrialization can be realized easily.

The invention discloses a high-performance, strong confinement pure blue CsPbBr 3 A quantum dot and a low-temperature preparation method and application thereof, the preparation method includes the following steps: (1) synthesis of a precursor solution; (2) anti-solvent recrystallization; (3) purification. Cs containing Cs was first prepared by cesium and lead sources without elements other than cesium / lead / bromine + and [PbBr 6 ] 4 The precursor solution of ‑, using the difference between the solubility of the precursor solution in the polar solvent and the non-polar solvent, and using liquid nitrogen to reduce the temperature of the anti-solvent, suppressing the nucleation and growth of the precursor, precipitating crystals, and obtaining pure blue light emission of ultra-small quantum dots. This high-performance, strongly confined pure blue CsPbBr 3 Quantum dots have strong quantum confinement and high exciton binding energy, and have great application prospects in the field of LED devices.

The invention relates to a chiral perovskite semiconductor circular polarization luminescence enhancement structure and a preparation method and application thereof, and belongs to the technical field of chiral photoelectric semiconductor materials and micro-nano devices. According to the structure, two layers of chiral perovskite semiconductor nanosheets are stacked through a controllable torsion angle to form a homojunction, and the torsion angle ranges from 0 degree to 90 degrees. According to the present invention, by adjusting the interlayer torsion angle, the continuous regulation and the significant enhancement of the circular polarization light emitting polarization degree are achieved, and especially during the parallel stacking (0 degree torsion angle), the circular polarization light emitting polarization degree is improved by 3 times compared with the single nanosheet and the vertical stacking (90 degree torsion angle). The enhancement effect is derived from inter-layer coupling dependent on a torsion angle, spin selective charge transfer is promoted, exciton binding energy is enhanced, and electron-phonon scattering is inhibited. The invention provides an effective way for regulating and controlling the polarization degree through the torsion angle, and is suitable for the fields of circular polarization luminescent devices, spin optoelectronic devices, quantum information processing and the like.

The present invention discloses a small molecule hole transporting material, a preparation method thereof, and an organic solar cell using the material. A hole transporting material is prepared by using carbazole as the main body and modifying it with a phosphoric acid group. This material has a small steric hindrance, can strengthen the intermolecular force, expands the thermal range of the mesophase of the molecule by improving the molecular crystallinity, and such molecules have the characteristics of low exciton binding energy, high charge transport efficiency, and good film-forming property. It is suitable for the preparation of high-efficiency organic solar cells, has the advantages of large-area preparation of organic solar cells, mass production and commercialization, and obtains an energy conversion efficiency with a relatively high reproducibility and a photoelectric conversion efficiency of 17.397%, which is of great significance for promoting organic solar cells.

The invention relates to the technical field of nanotechnology and light-emitting display, and provides a blue-light perovskite quantum dot film and an electroluminescent diode and preparation thereof. Obtaining high fluorescence yield (PLQY) gt by adopting a bromine ion-rich solution chemical synthesis method; the preparation method comprises the following steps: preparing an organic ligand quantum dot PQD-1 and an inorganic ligand quantum dot PQD-2 from 90% blue light emitting perovskite quantum dots through a ligand exchange process, and then preparing a quantum dot film with a three-layer structure consisting of a PQD-1 layer, a zinc chloride passivation layer and a PQD-2 layer, and finally, forming the electroluminescent diode with a transparent conductive oxide anode TOC, a hole transport layer material HTL, an electron transport layer material ETL and a metal cathode CL. According to the electroluminescent diode disclosed by the invention, Auger recombination is inhibited by remarkably reducing exciton binding energy, and the electron injection rate is reduced to be balanced with the hole injection rate; the electroluminescent diode is high in current efficiency and external quantum efficiency, good in stability and long in service life.

The invention discloses a method for adjusting the optical performance of a two-dimensional material, and belongs to the technical field of two-dimensional materials. The method comprises the following steps: obtaining a composite substrate, wherein the composite substrate comprises a target substrate and a two-dimensional transition metal chalcogenide film transferred to the surface of the target substrate; and annealing the composite substrate for at least 6 hours at the temperature of 260-320 DEG C in an inert atmosphere. The method is easy and convenient to operate, high in universality, small in damage to the two-dimensional material and capable of changing the Van der Waals gap between the two-dimensional material and the target substrate, so that the electronic band gap and exciton binding energy of the two-dimensional material are accurately regulated and controlled, and the optical performance of the two-dimensional material is improved.

The present invention relates to the field of nanotechnology and light-emitting display technology, and provides a blue light perovskite quantum dot film and an electroluminescent diode and their preparation. A bromide-rich solution chemical synthesis method is used to obtain blue light-emitting perovskite quantum dots with a high fluorescence yield (PLQY)>90%, and an organic ligand quantum dot PQD-1 and an inorganic ligand quantum dot PQD-2 are obtained by a ligand exchange process. Then, a three-layer structure quantum dot film consisting of a PQD-1 layer, a zinc chloride passivation layer, and a PQD-2 layer is prepared, and finally an electroluminescent diode is formed with a transparent conductive oxide anode TOC, a hole transport layer material HTL, an electron transport layer material ETL, and a metal cathode CL. The electroluminescent diode of the present invention significantly reduces the exciton binding energy to suppress Auger recombination, and reduces the electron injection rate to achieve a balance with the hole injection rate; the electroluminescent diode of the present invention has high current efficiency and external quantum efficiency, good stability, and a long working life.

The invention discloses a thiazole amine salt material for preparing a two-dimensional perovskite structure and a preparation method thereof. The thiazole amine salt material has the chemical formula:C3H4NSX, wherein the X element is any halogen element; and the thiazole amine salt material is prepared from thiazole and a material containing halogen acid in a weight ratio of 1 to 1. The preparation method is simple, does not pollute the environment, and is convenient for large-scale production. Solar cells of the two-dimensional perovskite structure prepared from the thiazole amine salt material have excellent electrical properties such as reducing exciton binding energy, enhancing charge transfer and accelerating charge transport, and long-term stabile perovskite solar cells can be realized.

The invention relates to the technical field of photocatalytic materials, in particular to a covalent organic framework material as well as a preparation method and application thereof. The covalent organic framework material has a repeating unit with a structure as shown in a formula I. A covalent organic framework material based on a benzothiadiazole (BT) core is modified through an electron donating group-OCH3, a non-uniform p-pi conjugated system is further constructed through the synergistic effect of-F and-OCH3, the electronic structure of the COF material is accurately regulated and controlled, a built-in electric field is enhanced, exciton binding energy is reduced, and the shallow trap life is prolonged; according to the preparation method, the formation of deep electron traps and charge recombination are effectively inhibited, the photocatalytic performance is improved, a novel material with enhanced performance is provided for repairing a radioactive pollution environment, and uranium (VI) reduction can be efficiently catalyzed under an illumination condition.

The invention discloses a preparation method and application of photocatalytic carbon dioxide reduction based on dielectric constant regulation and control, organic-inorganic hybrid perovskite-(PEA) 2PbBr4 and (EOA) 2PbBr4 with different dielectric constants are chemically synthesized at room temperature, and the PEA 2PbBr4 and the (EOA) 2PbBr4 are applied to photocatalytic carbon dioxide reduction for the first time. Compared with (PEA) 2PbBr4, (EOA) 2PbBr4 shows higher catalytic activity, and the result shows that the CO generation rate of the EOA 2PbBr4 reaches 18.69 [mu] mol.g <-1 >. H <-1 >. The results are attributed to the existence of carboxyl in the (EOA) 2PbBr4, so that the positive and negative charge centers of O and H are not overlapped, and larger polarity and dielectric constant are generated. The difference of dielectric constants with an inorganic layer is reduced, the dielectric confinement effect is weakened, and relatively small exciton binding energy is shown, so that the separation of photo-induced electrons and holes is promoted, the photocatalytic carbon dioxide reduction performance is enhanced, and potential application prospects are achieved.

The invention relates to a porphyrin-modified organic-inorganic hybrid perovskite nano-film material and a preparation method thereof. Porphyrin molecules containing carboxyl and amino functional groups are utilized to modify organic-inorganic hybrid perovskite, and specific functional groups of the porphyrin molecules interact with defect sites contained in a perovskite structure, and the functionalized nano-film material is prepared. The porphyrin-functionalized organic-inorganic hybrid perovskite nano-film material synthesized by the invention has enhanced nonlinear optical performance in near-infrared light areas of femtosecond and nanosecond scales, which is due to the effect of porphyrin molecules and a perovskite structure, the perovskite structure is stabilized, and larger exciton binding energy is obtained. And moreover, the nonlinear optical performance is also synergistically enhanced by photoinduced charge transfer between porphyrin molecules and perovskite. Therefore, the preparation method is simple, the prepared material is good in stability and controllable in operation, and rich experience is provided for expanding the application of the perovskite film material in the nonlinear optical field.

The invention relates to the field of photoelectric device materials, in particular to a blue light scintillator material and a preparation method and application thereof. A trace amount of Pb < 2 + > ions are doped in AnZnBr4 with relatively weak luminous intensity to serve as an optical active center, so that the absorption coefficient and exciton binding energy of the halide material can be improved, and the luminous property and scintillation property of the halide are further improved. An AnZnBr4: Pb zero-dimensional halide containing different organic groups is assembled by using a simple and convenient low-temperature wet chemical method, and the maximum emission wavelength, the half-peak width and the color purity of the AnZnBr4: Pb zero-dimensional halide are adjustable. Compared with low luminous activity of original zinc halide, trace Pb < 2 + > doping significantly promotes formation of STEs, improves emission efficiency of the STEs, obtains excellent scintillation response, has ultrahigh structural stability and spectral stability, realizes high-performance underwater X-ray imaging, and has broad application prospects. The technical problem that an existing blue light-emitting material is difficult to apply to an underwater environment is solved.

To provide an organic thin film solar cell having higher power generation efficiency.SOLUTION: The organic thin film solar battery 1 includes a pair of electrodes 311, and a photoelectric conversion layer 8 located between them, wherein the photoelectric conversion layer 8 is composed of at least a donor material and an accepter material, and exciton binding energy of the donor material and the accepter material is 0. 45eV or less. The donor material and the accepter material preferably have a band gap of 3eV or more or an optical gap of 2. 5eV or more.SELECTED DRAWING: Figure 1