1. Patent Search
  2. Details

SOLVENT-FREE AND LIGAND-FREE BALL MILLING METHOD FOR PREPARATION OF CESIUM LEAD TRIBROMIDE QUANTUM DOT

20230220276 · 2023-07-13

    Inventors

    Cpc classification

    International classification

    Abstract

    A solvent-free and ligand-free ball milling method for preparation of cesium lead tribromide (CsPbBr.sub.3) quantum dot is provided. First, mixing a Cs source, a Pb source, and a Br source as per a molar ratio of Cs source:Pb source:Br source is 1:1˜6:1˜9, and then adding polymethyl methacrylate (PMMA) to obtain a mixture. The mixture is milled for 1-2 hours at a rotation speed in a range of 360˜630 revolutions per minute (r/min) in a ball milling device, obtaining CsPbBr.sub.3 quantum dot. The method has advantages such as simple process, easy industrial production, no solvent, no organic ligand, low cost, and environmental protection. A quantum yield of product obtained by the method is up to 78%, and the product has a strong environmental stability. A preparation temperature of the product is low, and the reaction can be completed at a room temperature without a high temperature treatment.

    Claims

    1. A solvent-free and ligand-free ball milling method for preparation of cesium lead tribromide (CsPbBr.sub.3) quantum dot, comprising: mixing a Cs source, a Pb source, and a Br source as per a molar ratio of Cs source:Pb source:Br source being 1:1˜6:1˜9, and then adding polymethyl methacrylate (PMMA) to obtain a mixture; milling the mixture for 1˜2 hours at a rotation speed in a range of 360˜630 revolutions per minute (r/min) in a ball milling device, obtaining a product of CsPbB.sub.3 quantum dot; wherein the Cs source is one of cesium bromide (CsBr) and cesium stearate (C.sub.18H.sub.35CsO.sub.2), the Pb source is one of lead bromide (PbBr.sub.2) and lead stearate (C.sub.36H.sub.70O.sub.4Pb), the Br source is potassium bromide (KBr); and wherein a total mass of the Cs source, the Pb source, and the Br source accounts for 0.5%˜2.5% of a total mass of the Cs source, the Pb source, the Br source and the PMMA.

    2. The solvent-free and ligand-free ball milling method for preparation of CsPbBr.sub.3 quantum dot according to claim 1, wherein the Cs source is the C.sub.18H.sub.35CsO.sub.2, the Pb source is the PbBr.sub.2, and the Br source is the KBr.

    3. The solvent-free and ligand-free ball milling method for preparation of CsPbBr.sub.3 quantum dot according to claim 1, wherein a molar ratio of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr is 1:4:7.

    4. The solvent-free and ligand-free ball milling method for preparation of CsPbBr.sub.3 quantum dot according to claim 1, wherein the total mass of the Cs source, the Pb source, and the Br source accounts for 0.75% of the total mass of the Cs source, the Pb source, the Br source and the PMMA.

    5. The solvent-free and ligand-free ball milling method for preparation of CsPbBr.sub.3 quantum dot according to claim 1, wherein the rotation speed for milling is 500 r/min.

    6. The solvent-free and ligand-free ball milling method for preparation of CsPbBr.sub.3 quantum dot according to claim 1, wherein milling balls in the ball milling device are zirconia balls, and particle sizes of the zirconia balls are in a range of 2 mm˜8 mm.

    Description

    BRIEF DESCRIPTION OF DRAWINGS

    [0017] FIG. 1 is a fluorescence spectrum of products prepared with different ball milling rotation speeds in an embodiment 1.

    [0018] FIG. 2 is a fluorescence spectrum of products prepared with different perovskite sources in an embodiment 2.

    [0019] FIG. 3 is a fluorescence spectrum of products prepared with mass ratios of different perovskite sources in an embodiment 3.

    [0020] FIG. 4 is a fluorescence spectrum of products prepared with different molar ratios of C.sub.18H.sub.35CsO.sub.2 and PbBr.sub.2 in an embodiment 4.

    [0021] FIG. 5 is a fluorescence spectrum of products prepared with different molar ratios of C.sub.18H.sub.35CsO.sub.2 and KBr in an embodiment 5.

    [0022] FIG. 6 is a fluorescence spectrum of products prepared with different molar ratios of C.sub.18H.sub.35CsO.sub.2, PbBr.sub.2 and KBr in an embodiment 6.

    [0023] FIG. 7 is a fluorescence spectrum of a product prepared in an embodiment 7.

    [0024] FIG. 8 shows a photograph of the product prepared in the embodiment 7 under an UV lamp of 365 nm.

    DETAILED DESCRIPTION OF EMBODIMENTS

    [0025] The disclosure adopts a Cs source, a Pb source, and a Br source as a perovskite source, the Cs source is one of CsBr and C.sub.18H.sub.35CsO.sub.2, the Pb source is one of PbBr.sub.2 and C.sub.36H.sub.70O.sub.4Pb, the Br source is KBr. Mixing the Cs source, the Pb source, and the Br source as per a molar ratio of Cs source:Pb source:Br source is 1:1˜6:1˜9, and then adding PMMA polymer material to obtain a mixture; in the mixture, a total mass of the Cs source, the Pb source, and the Br source accounts for 0.5%˜2.5% of a total mass of the Cs source, the Pb source, the Br source and the PMMA. Preferably, the total mass of the Cs source, the Pb source, and the Br source accounts for 0.75% of the total mass of the Cs source, the Pb source, the Br source and the PMMA. Then milling the mixture for 1˜2 hours at a rotation speed in a range of 360˜630 r/min (also referred to as in a range of 360 r/min to 630 r/min) in a ball milling device, an obtained product is CsPbB3 quantum dot. Preferably, the rotation speed is 500 r/min and time for ball milling is 1 hour.

    [0026] Preferably, the perovskite source consists of the C.sub.18H.sub.35CsO.sub.2, the PbBr2, and the KBr; a molar ratio of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr is 1:4:7.

    [0027] In a process of ball milling, milling balls in the ball milling device are zirconia balls, particle sizes of the zirconia balls are in a range of 2 mm˜8 mm; Preferably, the particle sizes of the zirconia balls consist of 2 mm, 4 mm, and 8 mm.

    [0028] Specific embodiments of the disclosure are provided below. It should be noted that the disclosure is not limited to the following specific embodiments, and any equivalent transformation based on the technical schemes of the present application should be within the protection scope of the disclosure.

    EMBODIMENT 1

    [0029] The embodiment 1 adopts CsBr, PbBr.sub.2, and KBr as perovskite sources, for each of the perovskite sources, a molar ratio of CsBr:PbBr.sub.2:KBr is 1:1:3. Mixing the perovskite sources and PMMA polymer materials to obtain mixtures, and in each of the mixtures, mass of the perovskite source accounts for 1.5% of a total mass of the perovskite source and the PMMA polymer material. For each of the mixtures, performing the same operations as follow: adding the mixture into a 100 mL ball milling pot; then adding the zirconia balls with particle sizes consisting of 2 mm, 4 mm, and 8 mm into the ball milling pot; milling the mixture in a planetary ball milling device eventually. For the mixtures, rotation speeds for milling are 360 r/min, 500 r/min, and 600 r/min respectively, CsPbBr.sub.3 PQDs/PMMA luminescent materials are obtained after the mixtures are milled for 1 hour respectively.

    [0030] Separating the zirconia balls and the luminescent materials, measuring each of the luminescent materials to obtain a fluorescence spectrum as shown in FIG. 1. As it shown in the FIG. 1, the fluorescence intensity of the luminescent materials is the strongest when the rotation speed for milling is 500 r/min.

    EMBODIMENT 2

    [0031] The embodiment 2 adopts “CsBr+PbBr.sub.2+KBr”, “C.sub.18H.sub.35CsO.sub.2+PbBr.sub.2+KBr”, “C.sub.18H.sub.35CsO.sub.2+C.sub.36H.sub.70O.sub.4Pb+KBr”, and “cesium carbonate (Cs.sub.2CO.sub.3)+PbBr.sub.2+KBr” as perovskite sources respectively, for each of the perovskite sources, a molar ratio of Cs source:Pb source:Br source is the same as that in the embodiment 1, that is, the molar ratio of Cs source:Pb source:Br source is 1:1:3; mass of the perovskite source is the same as that in the embodiment 1, that is, for each of the perovskite sources, the mass of the perovskite source accounts for 1.5% of a total mass of the perovskite source and the PMMA polymer material. A rotation speed for milling is 500 r/min and time for milling is 1 hour in the embodiment 2. CsPbBr.sub.3 PQDs/PMMA luminescent materials are obtained eventually.

    [0032] Separating the zirconia balls and the luminescent materials, measuring each of the luminescent materials to obtain a fluorescence spectrum as shown in FIG. 2. As it shown in the FIG. 2, compared with the combination of “CsBr+PbBr.sub.2+KBr”, fluorescence intensity of the CsPbBr.sub.3 PQDs/PMMA luminescent materials is weaker when the perovskite source is the combination of “C.sub.18H.sub.35CsO.sub.2+PbBr.sub.2+KBr”; however, its full width at a half-maximum is the narrowest, which is conducive to being used as a backlight display material. It can be seen that the combination of “C.sub.18H.sub.35CsO.sub.2+PbBr.sub.2+KBr” is the best perovskite source.

    EMBODIMENT 3

    [0033] The embodiment 3 adopts C.sub.18H.sub.35CsO.sub.2, PbBr.sub.2, and KBr as perovskite sources, for each of the perovskite sources, a molar ratio of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr is 1:1:3. Mixing the perovskite sources and PMMA polymer materials to obtain mixtures respectively. In the mixtures, mass of the perovskite sources accounts for 0.5%, 0.75%, 1.0% and 1.25% of a total mass of the perovskite sources and the PMMA polymer materials respectively. For each of the mixtures, performing the same operations: adding the mixture into a 100 mL ball milling pot; then adding the zirconia balls with particle sizes consisting of 2 mm, 4 mm, and 8 mm into the ball milling pot; milling the mixture in a planetary ball milling device eventually, and a rotation speed for milling is 500 r/min. CsPbBr.sub.3 PQDs/PMMA luminescent materials are after the mixtures are milled for 1 hour.

    [0034] Separating the zirconia balls and the luminescent materials, measuring the luminescent materials to obtain a fluorescence spectrum as shown in FIG. 3. As it shown in the FIG. 3, as the mass of the perovskite source increases, the fluorescence intensity of the luminescent material increases first and then decreases. When the mass of the perovskite source accounts for 0.75% of the total mass of the perovskite source and the PMMA polymer material, the fluorescence intensity of the luminescent material is the strongest.

    EMBODIMENT 4

    [0035] The embodiment 4 adopts C.sub.18H.sub.35CsO.sub.2, PbBr.sub.2, and KBr as perovskite sources, molar ratios of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr are 1:1:3, 1:2:3, 1:3:3, 1:4:3, 1:5:3, and 1:6:3 respectively. For each of the perovskite sources, performing the same operations: mixing the perovskite source and PMMA polymer material to obtain a mixture; in the mixture, mass of the perovskite source accounts for 0.75% of a total mass of the perovskite source and PMMA polymer material; adding the mixture into a 100 mL ball milling pot; then adding the zirconia balls with particle sizes consisting of 2 mm, 4 mm, and 8 mm into the ball milling pot; milling the mixture in a planetary ball milling device eventually, and a rotation speed for milling is 500 r/min. CsPbBr.sub.3 PQDs/PMMA luminescent materials are obtained after the mixtures are milled for 1 hour.

    [0036] Separating the zirconia balls and the luminescent materials, measuring the luminescent materials to obtain a fluorescence spectrum as shown in FIG. 4. As it shown in the FIG. 4, as the molar ratio of the PbBr.sub.2 increases, the fluorescence intensity of the luminescent materials increases first and then decreases. When the molar ratio of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2 is 1:4, the fluorescence intensity of the luminescent material is the strongest.

    EMBODIMENT 5

    [0037] The embodiment 5 adopts C.sub.18H.sub.35CsO.sub.2, PbBr.sub.2, and KBr as perovskite sources, molar ratios of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr are 1:1:1, 1:1:2, 1:1:3, 1:1:4, 1:1:5, 1:1:6, 1:1:7, 1:1:8, and 1:1:9 respectively. For each of the perovskite sources, performing the same operations: mixing the perovskite source and PMMA polymer material to obtain a mixture; in the mixture, mass of the perovskite source accounts for 0.75% of a total mass of the perovskite source and PMMA polymer material; adding the mixture into a 100 mL ball milling pot, then adding the zirconia balls with particle sizes consisting of 2 mm, 4 mm, and 8 mm into the ball milling pot; milling the mixture in a planetary ball milling device eventually, and a rotation speed for milling is 500 r/min. CsPbBr.sub.3 PQDs/PMMA luminescent materials are obtained after the mixtures are milled for 1 hour.

    [0038] Separating the zirconia balls and the luminescent materials, measuring the luminescent materials to obtain a fluorescence spectrum as shown in FIG. 5. As it shown in the FIG. 5, as the molar ratio of the KBr increases, the fluorescence intensity of the luminescent materials increases first and then decreases. When the molar ratio of C.sub.18H.sub.35CsO.sub.2:KBr is 1:7, the fluorescence intensity of the luminescent materials is the strongest.

    EMBODIMENT 6

    [0039] The embodiment 6 adopts C.sub.18H.sub.35CsO.sub.2, PbBr.sub.2, and KBr as perovskite sources, molar ratios of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr are 1:X:Y, X=1, 4; Y=3, 6, 7. For each of the perovskite sources, performing the same operations: mixing the perovskite source and PMMA polymer material to obtain a mixture; in the mixture, mass of the perovskite source accounts for 0.75% of a total mass of the perovskite source and PMMA polymer material; adding the mixture into a 100 mL ball milling pot, then adding the zirconia balls with particle sizes consisting of 2 mm, 4 mm, and 8 mm into the ball milling pot; milling the mixture in a planetary ball milling device eventually, and a rotation speed for milling is 500 r/min. CsPbBr.sub.3 PQDs/PMMA luminescent materials are obtained after the mixtures are milled for 1 hour.

    [0040] Separating the zirconia balls and the luminescent materials, measuring the luminescent materials to obtain a fluorescence spectrum as shown in FIG. 6. As it shown in the FIG. 6, when the molar ratio of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr is 1:4:7, the fluorescence intensity of the luminescent materials is the strongest.

    EMBODIMENT 7

    [0041] The embodiment 7 adopts C.sub.18H.sub.35CsO.sub.2, PbBr.sub.2, and KBr as a perovskite source, a molar ratio of C.sub.18H.sub.35CsO.sub.2:PbBr.sub.2:KBr is 1:4:7. Mixing the perovskite source and PMMA polymer material to obtain a mixture, mass of the perovskite source accounts for 0.75% of a total mass of the perovskite source and PMMA polymer material; adding the mixture into a 100 mL ball milling pot, then adding the zirconia balls with particle sizes consisting of 2 mm, 4 mm, and 8 mm into the ball milling pot; milling the mixture in a planetary ball milling device eventually. A rotation speed for milling is 500 r/min; CsPbBr.sub.3 PQDs/PMMA luminescent material is obtained after the mixture is milled for 1 hour.

    [0042] Separating the zirconia balls and the luminescent material, measuring the luminescent material to obtain a fluorescence spectrum as shown in FIG. 7. As it shown in the FIG. 7, a half-peak width of the fluorescence spectrum of the luminescent material is 20.2 nm. A photograph of the luminescent material under the 365 nm UV lamp is shown in FIG. 8, which shows that luminescent performance of the luminescent material is good.