Technology for enhancing luminous intensity of silver-doped zinc sulfide fluorescent material through charge compensation

Abstract

The invention discloses a technology for enhancing the luminous intensity of a silver-doped zinc sulfide fluorescent material through a charge compensation agent, which comprises the following steps: weighing raw materials ZnS and AgNO3, a sintering aid NH4Cl, charge compensation agents H3BO3, Au2O3, Y2O3, Lu2O3 and other materials according to a certain proportion, grinding until the materials are uniformly mixed, calcining for 0.5-3 hours at the temperature of 700-1000 DEG C by using a high-temperature solid-phase method, and cooling to room temperature to obtain the silver-doped zinc sulfide fluorescent material. The ZnS: Ag < + > fluorescent material powder with excellent luminescence performance is obtained. According to the technology for enhancing the luminous intensity of the silver-doped zinc sulfide fluorescent material through the charge compensation agent, the luminous intensity can be remarkably enhanced.

Description

Technical Field

[0001] The present invention relates to a technology for enhancing the luminous intensity of silver-doped zinc sulfide fluorescent materials by charge compensation. The technology adopts a high-temperature solid phase method and can prepare ZnS:Ag with excellent luminous performance by selecting and adjusting the addition of flux and charge compensator. + Fluorescent material, ZnS:Ag + The excitation and emission spectrum intensities of fluorescent materials have been effectively improved, and this technology belongs to the field of optoelectronic functional materials. Background Art

[0002] In neutron detection technology and cathode ray imaging technology, ZnS:Ag is used + The fluorescent screen made of luminescent materials such as ZnS:Ag is a key device for scintillator detectors and cathode ray imaging, and is an important component for realizing cathode ray luminescence and X-ray luminescence. + The luminescent material is a highly efficient X-ray absorbing material that can convert X-rays into visible light. It is more efficient than Gd2O2S:Tb in the range of lower energy X-rays (<50KeV). 3+ It has higher light conversion efficiency and can obtain higher radiation efficiency under cathode ray excitation. ZnS:Ag + Compared with other luminescent materials, ZnS:Ag has the advantages of simple preparation process, stable performance and low cost. + Fluorescent materials have significant research value and important research significance in improving cathode ray luminescence performance and realizing scintillator detection.

[0003] ZnS:Ag + The fluorescent material is an ion-doped zinc sulfide-based fluorescent material. It uses ZnS as the matrix and introduces other metal elements, transition metals and rare earth elements to generate additional energy levels in the band gap of ZnS, thereby forming a new electron-hole recombination center. Different elements are introduced into the ZnS lattice by doping to increase its electron transition probability and achieve luminescence. ZnS is a wide-gap II-VI compound semiconductor material with an excellent luminescence performance due to its band gap width of up to 3.67eV at room temperature. It has always been a hot topic in luminescence research. In 1998, Hao et al. synthesized a ZnS:Ag + The addition of HSCH2COOH not only affects the formation of ZnS, but also its spectral properties. In 2007, Luo et al. synthesized ZnS:Ag by hydrothermal method. + and (Zn, Cd)S:Ag nanoparticles (50-100nm), and studied the effects of hydrothermal treatment on the physical and luminescent properties of the nanoparticles. +The luminescence intensity was enhanced by 10 times. In 2009, Qu Hua et al. prepared ZnS:Ag by hydrothermal method at 200℃ for 6h. + Nanoluminescent materials. In 2006, Jian et al. synthesized ZnS:Ag using microwave radiation. + Nanocrystals, by reducing Zn-MPA synthesis through microwave radiation, produce a shell protective layer on the surface of nanocrystals, which can significantly improve the photoluminescence efficiency and photostability of nanocrystals. In 2016, Qu Haoying et al. prepared wurtzite ZnS:Ag by hydrothermal method. + ,Cr 3+ Co-doped nanomaterials were used to investigate the effects of different reaction times and different Cr and Ag doping ratios on the optical properties of ZnS nanomaterials. When the reaction time was 12h and the Cr and Ag doping ratios were 1%, the morphology and optical properties of the doped ZnS nanomaterials were optimal. The specific surface area and pore size distribution of Cr and Ag co-doped ZnS materials were calculated using N2 isothermal adsorption analysis technology and used for the adsorption study of four active dyes: MV, BRB, TCTBF and EB. However, the current ZnS:Ag + The luminous efficiency of fluorescent materials in scintillator detection and cathode ray tube applications still needs to be further improved. Summary of the invention

[0004] In order to improve the ZnS:Ag + The luminous efficiency of fluorescent materials, the present invention proposes a technology for enhancing the luminous intensity of silver-doped zinc sulfide fluorescent materials through charge compensation.

[0005] The present invention is in ZnS:Ag + In the preparation process of fluorescent materials, ZnS and AgNO3 are used as raw materials, and a high-temperature solid-phase method is adopted. By rationally designing and regulating flux NH4Cl and charge compensators H3BO3, Au2O3, Y2O3, Lu2O3 and other materials, enhanced luminescence is achieved.

[0006] The core of the present invention is to use ZnS:Ag + Based on blue light emitting phosphor, by adding charge compensator, B in charge compensator is introduced. 3+ 、Au 3+ , Y 3+ 、Lu 3+ Plasma builds a composite luminescence center and improves the electron transfer efficiency, thereby achieving the purpose of improving blue light emission. Because ZnS-based phosphors are semiconductor luminescence, they are mainly modified by doping with transition metal ions and rare earth ions to change their luminescence properties, and B 3+ It has transition metal-like properties. By introducing B 3+ , transition metals and rare earth ions Au 3+ , Y 3+、Lu 3+ Plasma, changing its band structure. 3+ 、Au 3+ , Y 3+ 、Lu 3+ Compared with Zn 2+ One more electron belongs to donor type doping; while Ag + Compared with Zn 2+ One less electron, which is acceptor type doping. 3+ 、Au 3+ , Y 3+ 、Lu 3+ Plasma and Ag + Co-doping can make two elements attract each other, especially co-doping with donor and acceptor impurities can increase the atomic bonding degree, thereby increasing the doping degree, electron concentration and mobility; multi-element co-doping narrows the band gap of zinc sulfide, and electrons can more easily transition from impurity energy levels into the conduction band with higher binding energy. By adding suitable charge compensators, luminescence enhancement can be achieved.

[0007] In the process of raw material selection, the present invention uses ZnS as the matrix raw material of the fluorescent material, which reduces the introduction of impurity ions. By combining with the flux NH4Cl, the temperature required for the reaction is reduced, the growth of the grains is promoted, and the doping of metal ions into the matrix lattice is promoted. By adding additional H3BO3, Au2O3, Y2O3, Lu2O3 and other materials as charge compensators for doping, the energy band structure of the material is changed. During the calcination process at a temperature of 700°C to 1000°C for 0.5 to 3h, ZnS:Ag with excellent luminescence performance is generated by a high-temperature solid phase method. + Fluorescent materials, the luminous intensity of fluorescent materials is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 The ZnS:Ag before and after the charge compensator H3BO3 is introduced into the present invention + Photoluminescence excitation spectrum of fluorescent material samples.

[0009] Figure 2 The ZnS:Ag before and after the charge compensator H3BO3 is introduced into the present invention + Photoluminescence emission spectra of fluorescent material samples.

[0010] Figure 3 The ZnS:Ag before and after the charge compensator H3BO3 is introduced into the present invention + Emission spectrum of fluorescent material sample under cathode ray excitation. DETAILED DESCRIPTION

[0011] The ZnS:Ag with excellent luminescence performance in the present invention+ The specific process of fluorescent materials is described in detail as follows:

[0012] (1) ZnS(AR) and AgNO3(AR) are used as raw materials, NH4Cl(AR) is selected as sintering aid, and H3BO3(AR), Au2O3(AR), Y2O3(AR)Lu2O3 and other materials are selected as charge compensators. + The amount of each raw material is calculated according to the stoichiometric ratio, where x is Ag + The doping amount of ions, x is 0.7at%, the doping amount of charge compensator is 0.7at%, and the content of sintering aid is 6wt% of the product;

[0013] (2) According to the preparation of 5g sample, the corresponding amount of ZnS, AgNO3, NH4Cl and H3BO3(AR), Au2O3(AR), Y2O3(AR)Lu2O3 raw materials were weighed using a precision electronic balance, the weighed raw materials were placed in an agate mortar, ground for 20 to 60 minutes to mix the raw materials evenly, and then placed in a 25ml alumina crucible;

[0014] (3) Select a 100ml alumina crucible, fill it with excess C powder, insert the 25ml crucible containing the raw materials into the 100ml crucible, and send it into the box-type resistance furnace;

[0015] (4) Start sintering, wherein the heating rate does not exceed 5°C / min, the sintering temperature is set to 800°C, and the holding time is 0.5 to 3 hours;

[0016] (5) After sintering, the furnace is cooled down, and the sample is taken out and ground to obtain ZnS:Ag with excellent luminescence performance. + Fluorescent material samples.

[0017] This fluorescent material sample uses H3BO3 as a charge compensator to synthesize ZnS:Ag + Fluorescent material.

[0018] Figure 1 ZnS:Ag + The excitation spectra of the fluorescent material samples before and after the charge compensator is added. The excitation spectra of the two samples are broadband spectra with peaks at 340nm.

[0019] Figure 2 ZnS:Ag + The emission spectra of the fluorescent material samples before and after adding the charge compensator, the samples have the highest emission peak at 445nm under the excitation of 340nm ultraviolet light, and have bright blue light emission.

[0020] Figure 3The prepared ZnS:Ag + The emission spectrum of the fluorescent material sample under cathode ray excitation shows that under cathode ray excitation, the sample has a high blue emission peak at 450nm, and charge compensation significantly enhances the luminescence intensity.

[0021] The peak positions of the excitation and emission spectra of the samples before and after the addition of the charge compensator did not change, but the intensity changed, indicating that after the charge compensation, a composite luminescence center was formed and the electron transfer efficiency was enhanced. The luminescence intensity of the sample after the charge compensator was added was significantly stronger than that of the sample without the charge compensator.

Claims

1. A technology for enhancing the luminescence intensity of zinc sulfide-doped silver fluorescent materials by charge compensators. The technology uses ZnS and AgNO3 as raw materials and NH4Cl as a sintering aid. By introducing charge compensators such as H3BO3, Au2O3, Y2O3, Lu2O3 and other metals, transition metals and rare earth ions, enhanced luminescence is achieved. By using a high-temperature solid-phase method, ZnS:Ag with excellent luminescence performance is obtained by calcining for 0.5 to 3 hours in a reducing atmosphere provided by C powder at 700°C to 1000°C. + Fluorescent materials to achieve enhanced luminous intensity.

Images