Preparation method of perovskite blue light illuminant film and white light emitting diode

Abstract

The invention provides a preparation method of a perovskite cyan light illuminant film and a white light emitting diode, the light emitting surface of the white light emitting diode is provided with the perovskite cyan light illuminant film, and the perovskite cyan light illuminant film can reduce the color temperature of the white light emitting diode. The color rendering index of the white light emitting diode is improved; the perovskite blue light illuminant film absorbs blue light which is emitted by the white light emitting diode and has a wavelength less than 455nm, and compensates for the deficiency of blue light with a wavelength range of 470-520nm; the chemical formula of the cyan light illuminant is CsPb (BrCl) 3: Ba; wherein Ba is a doped barium ion. According to the perovskite blue light illuminant film, the color rendering index of a WLED is improved, and meanwhile blue light emitted by an LED chip is absorbed, so that harm to a human body is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of auxiliary WLED light emitting, and in particular relates to a preparation method of a perovskite cyan light emitting body film and a white light emitting diode. Background Art

[0002] Perovskite quantum dots (QDs) can be used in light-emitting diodes (LEDs) due to their narrow emission half-width, high color purity, and tunable visible light band.

[0003] In particular, most of the current white light emitting diodes (WLEDs) produce white light by combining blue InGaN LED chips (440-460nm) with YAG phosphors (emitting yellow light). Due to the lack of red bands in their emission spectra, these WLEDs have a low color rendering index (CRI<80) and a high color temperature (CCT>5000K). Although the addition of red phosphors can improve the color rendering index of WLEDs, it is difficult for their color rendering index to reach above 95.15. This is because red phosphors cannot fully compensate for the lack of light in the cyan region (470-520nm) between blue and green light, a phenomenon known as the "cyan gap". In addition, the "blue overshoot" phenomenon, which is currently characterized by the strong blue light emitted by LED chips, has been identified as a potential health problem. Studies have shown that excessive blue light exposure is associated with a range of adverse effects, including increased eye damage, increased susceptibility to depression and psychological disorders, disruption of the body's natural circadian rhythm, and impact on the sleep-wake cycle.

[0004] Therefore, it is necessary to develop a cyan perovskite luminescent body to improve the color rendering index of WLED while absorbing the blue light emitted by the LED chip to reduce the harm to the human body, so it needs to be improved. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a perovskite cyan luminescent body film and a white light emitting diode, which improves the color rendering index of WLED and absorbs the blue light emitted by the LED chip to reduce the harm to the human body.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A white light emitting diode, wherein a perovskite cyan luminescent body film is arranged on a light emitting surface of the white light emitting diode, wherein the perovskite cyan luminescent body film can reduce the color temperature of the white light emitting diode and improve the color rendering index of the white light emitting diode;

[0008] The perovskite cyan luminescent body film absorbs the blue light with a wavelength less than 455 nm emitted by the white light emitting diode, and compensates for the loss of cyan light with a wavelength range of 470-520 nm;

[0009] The chemical formula of the cyan luminescent body is CsPb(BrCl)3:Ba;

[0010] Here, Ba is a doped barium ion.

[0011] Furthermore, the perovskite cyan luminescent film can improve the special chromaticity index R6-R10 value of the white light emitting diode defined in the CIE 13.3-1995 standard.

[0012] Furthermore, the perovskite cyan luminescent film compensates for the loss of cyan light in the wavelength range of 470-495 nm.

[0013] Furthermore, the perovskite cyan light emitting body film can be used as a part of a lampshade or directly used as a lampshade.

[0014] In the present application, the application form of the perovskite cyan light emitting body film is not limited to being set on the surface of the lampshade, but can also be directly used as the raw material of the lampshade, and the lampshade can be directly prepared and produced by existing technical means. Therefore, it is necessary to clearly point out that although the perovskite cyan light emitting body film of the present application has the technical feature of "film", its form is not limited to a soft state, but also includes a form with higher hardness.

[0015] Furthermore, the cyan light emitting body also includes an organic abrasive, and the organic abrasive is at least partially attached to the surface of CsPb(BrCl)3:Ba.

[0016] Furthermore, the organic abrasive includes one of 18-alkylphosphonic acid, potassium lauryl sulfate, n-octyl phosphoric acid, PIMA, and 2-hydroxy-NN,N-trimethylethylamine-4-methyl.

[0017] A method for preparing a perovskite cyan light emitting body film comprises the following steps:

[0018] A1. Ball milling synthesis:

[0019] The perovskite luminescent body is obtained by dry ball milling CsBr, PbCl2, BaBr2 and an organic grinding agent, wherein the perovskite luminescent body has a CsPb(BrCl)3:Ba perovskite structure;

[0020] A2. Film preparation:

[0021] The perovskite luminescent body prepared in step A1 is mixed with UV glue, and ethyl acetate is added to dilute the glue, and stirred until fully dissolved to obtain a mixture; the mixture is scraped and coated on the surface of the lampshade, and cured with an ultraviolet lamp to form a perovskite cyan luminescent body film on the surface of the lampshade.

[0022] Furthermore, the ball milling time in step A1 is at least 1 hour, and the ball milling speed is 50-500 r / min.

[0023] Furthermore, the mass ratio of the perovskite light emitting body to the UV glue in step S2 is 1:10.

[0024] A method for preparing a perovskite cyan light emitting body film comprises the following steps:

[0025] A1. Ball milling synthesis:

[0026] The perovskite luminescent body is obtained by dry ball milling CsBr, PbCl2, BaBr2 and an organic grinding agent, wherein the perovskite luminescent body has a CsPb(BrCl)3:Ba perovskite structure;

[0027] A2. Preparation of lampshade:

[0028] The perovskite light-emitting body prepared in step A1 is used as the raw material of the lampshade to participate in the preparation and production of the lampshade.

[0029] The beneficial effects of the present invention are mainly reflected in:

[0030] (1) The perovskite cyan luminescent film of the present invention can reduce the color temperature of white light emitting diodes and improve the color rendering index of WLEDs, while absorbing the blue light emitted by LED chips to reduce harm to the human body. Specifically: the perovskite cyan luminescent film absorbs the blue light with a wavelength less than 455nm emitted by white light emitting diodes and compensates for the loss of cyan light with a wavelength range of 470-520nm.

[0031] (2) When synthesizing CsPb(BrCl)3:Ba perovskite luminophores, the use of organic abrasives can accelerate solid-state reactions by friction, and isolate quantum dots prepared by the reaction to prevent them from agglomerating, thereby better controlling the luminescence performance and wavelength of the synthesized quantum dots. At the same time, the preparation method of the present invention is more suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 PL spectrum of the sample prepared in Example 1 of the present invention;

[0033] Figure 2 is the LED emission spectrum of the LED and the covering film in Example 2 of the present invention;

[0034] Figure 3 PL spectrum of the sample prepared in Comparative Example 1 of the present invention;

[0035] Figure 4 The LED emission spectra of the LED and the cover film in Comparative Example 2 of the present invention;

[0036] Figure 5 This is the emission spectrum of undoped BaBr2 in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] Embodiment 1:

[0039] 425.6 mg CsBr, 445 mg PbCl2, 59.4 mg BaBr2 and 698 mg 18-alkylphosphonic acid were mixed.

[0040] The powder was placed in a ball mill equipped with agate balls and ball milled for 1 hour at a rotation speed of 230 r / min to obtain the cyan luminescent body CsPb(BrCl)3:Ba.

[0041] Experimental analysis: Figure 1 PL spectrum of the sample in Example 1.

[0042] Embodiment 2:

[0043] 425.6 mg CsBr, 445 mg PbCl2, 59.4 mg BaBr2 and 698 mg 18-alkylphosphonic acid were mixed.

[0044] Place the above powder in a ball mill equipped with agate balls, rotate at 230r / min, and continue ball milling for 1 hour. Take 500mg of the prepared sample (cyan light emitter CsPb(BrCl)3:Ba) and mix it with 5g UV glue, add 4.3g ethyl acetate to dilute the glue, and stir until it is fully dissolved. Finally, use a wire rod to evenly scrape it on the PET lampshade, and use a UV light box to cure it to form a perovskite cyan light emitter film on the surface of the PET lampshade. Place the PET lampshade with the perovskite cyan light emitter film on the light-emitting surface of the WLED.

[0045] Experimental analysis: Figure 2 As shown in the figure, compared with the original WLED, the blue light intensity of the WLED covered by the thin film (perovskite cyan light emitter film) is weakened, and the cyan light intensity is enhanced. This is because the prepared film emits 473nm cyan light by absorbing 450nm blue light. The color rendering index, color temperature, color coordinates, and illumination of different WLEDs are shown in Table 1 below:

[0046]

[0047] The above results show that the prepared film can improve the color rendering index of WLED while reducing its color temperature.

[0048] Embodiment 3:

[0049] 425.6 mg CsBr, 445 mg PbCl2, 59.4 mg BaBr2 and 698 mg 18-alkylphosphonic acid were mixed.

[0050] The above powder was placed in a ball mill equipped with agate balls at a rotation speed of 230 r / min and ball milling was continued for 1 hour to obtain the cyan luminescent body CsPb(BrCl)3:Ba.

[0051] The prepared cyan luminescent body CsPb(BrCl)3:Ba is directly used as the raw material of the lampshade to participate in the preparation and production of the lampshade. The preparation method of the lampshade can refer to any existing technology and will not be repeated here.

[0052] Comparative Example 1:

[0053] Mix 425.6 mg CsBr, 445 mg PbCl2, and 59.4 mg BaBr2;

[0054] The above powder was placed in a ball mill equipped with agate balls, the rotation speed was 230 r / min, and the ball milling was continued for 1 hour.

[0055] Experimental analysis: Figure 3 PL spectrum of the sample of comparative example 1. As a comparison (see comparative example 1), the luminescence intensity of the sample prepared by adding the organic abrasive 18-alkylphosphonic acid is twice that of the sample without adding the organic abrasive. This is because the addition of 18-alkylphosphonic acid can isolate the quantum dots prepared by the reaction, prevent them from agglomerating, and enhance their luminescence intensity.

[0056] Comparative Example 2:

[0057] Mix 425.6 mg CsBr, 445 mg PbCl2, and 59.4 mg BaBr2;

[0058] Place the above powder in a ball mill equipped with agate balls, rotate at 230r / min, and continue ball milling for 1 hour. Take 500mg of the prepared sample and mix it with 5g UV glue, add 4.3g ethyl acetate to dilute the glue, and stir until it is fully dissolved. Finally, use a wire rod to evenly scrape it on the PET lampshade, and use a UV light box to cure it to form a perovskite cyan light emitting body film on the surface of the PET lampshade. Place the PET lampshade with the perovskite cyan light emitting body film on the light-emitting surface of the WLED.

[0059] Experimental analysis: Figure 4 As shown in the figure, compared with the original WLED, the blue light intensity of the WLED covered by the film is weakened, and the cyan light is not significantly enhanced. The color rendering index, color temperature, color coordinates, and illumination of different WLEDs are shown in Table 2:

[0060]

[0061] As can be seen from Table 2, compared with Example 2, the film prepared in Comparative Example 2 absorbs less blue light and has lower cyan light emission intensity, resulting in no significant changes in the color rendering index, color temperature, color coordinates and R6-R10.

[0062] Comparative Example 3:

[0063] 425.6 mg CsBr, 445 mg PbCl2 and 698 mg 18-alkylphosphonic acid were mixed.

[0064] The above powder was placed in a ball mill equipped with agate balls, the rotation speed was 230 r / min, and the ball milling was continued for 1 hour.

[0065] Experimental analysis: Figure 5 As shown, the luminescence wavelength of the undoped BaBr2 sample is 434nm, which belongs to the blue light band and cannot emit cyan light.

[0066] The present invention illustrates the detailed preparation method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed preparation method, that is, it does not mean that the present invention must rely on the above-mentioned products and detailed preparation methods to be implemented. It should be clear to those skilled in the art that any improvement of the present invention, the combination or equivalent replacement of the raw materials of the product of the present invention, all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A white light emitting diode, characterized in that: A perovskite cyan luminescent film is disposed on the light emitting surface of the white light emitting diode, and the perovskite cyan luminescent film can reduce the color temperature of the white light emitting diode and improve the color rendering index of the white light emitting diode; The perovskite cyan luminescent body film absorbs the blue light with a wavelength less than 455 nm emitted by the white light emitting diode, and compensates for the loss of cyan light with a wavelength range of 470-520 nm; The chemical formula of the cyan luminescent body is CsPb(BrCl)3:Ba; Here, Ba is a doped barium ion.

2. A white light emitting diode according to claim 1, characterized in that: The perovskite cyan light emitting body film can improve the special chromaticity index R6-R10 value of the white light emitting diode defined in the CIE 13.3-1995 standard.

3. A white light emitting diode according to claim 1, characterized in that: The perovskite cyan luminescent film compensates for the loss of cyan light in the wavelength range of 470-495 nm.

4. A white light emitting diode according to claim 1, characterized in that: The perovskite cyan light emitting body film can be used as a part of a lampshade or directly used as a lampshade.

5. A white light emitting diode according to claim 1, characterized in that: The cyan light emitting body further includes an organic abrasive, which is at least partially attached to the surface of CsPb(BrCl)3:Ba.

6. A white light emitting diode according to claim 5, characterized in that: The organic abrasive includes one of 18-alkylphosphonic acid, potassium lauryl sulfate, n-octyl phosphoric acid, PIMA, and 2-hydroxy-NN,N-trimethylethylamine-4-methyl.

7. A method for preparing a perovskite cyan light emitting body film according to any one of claims 5-6, characterized in that: The steps include: A1. Ball milling synthesis: The perovskite luminescent body is obtained by dry ball milling CsBr, PbCl2, BaBr2 and an organic grinding agent, wherein the perovskite luminescent body has a CsPb(BrCl)3:Ba perovskite structure; A2. Film preparation: The perovskite luminescent body prepared in step A1 is mixed with UV glue, and ethyl acetate is added to dilute the glue, and stirred until fully dissolved to obtain a mixture; the mixture is scraped and coated on the surface of the lampshade, and cured with an ultraviolet lamp to form a perovskite cyan luminescent body film on the surface of the lampshade.

8. The method for preparing a perovskite cyan light emitting body film according to claim 7, characterized in that: The ball milling time in step A1 is at least 1 hour, and the ball milling speed is 50-500 r / min.

9. The method for preparing a perovskite cyan light emitting body film according to claim 7, characterized in that: The mass ratio of the perovskite light emitter to the UV glue in step S2 is 1:

10.

10. A method for preparing a perovskite cyan light emitting body film according to any one of claims 5-6, characterized in that: The steps include: A1. Ball milling synthesis: The perovskite luminescent body is obtained by dry ball milling CsBr, PbCl2, BaBr2 and an organic grinding agent, wherein the perovskite luminescent body has a CsPb(BrCl)3:Ba perovskite structure; A2. Preparation of lampshade: The perovskite light-emitting body prepared in step A1 is used as the raw material of the lampshade to participate in the preparation and production of the lampshade.

Images