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Method for improving light stability and fluorescence intensity of two-dimensional lead iodide

A fluorescence intensity, lead iodide technology, applied in chemical instruments and methods, luminescent materials, etc., can solve the problems of low thermal conductivity and can not improve the photostability of PbI well

Pending Publication Date: 2021-04-06
NORTHEAST NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Protect PbI 2 A common strategy is to deposit an organic polymer such as polydimethylsiloxane (PDMS) as an encapsulation layer on PbI 2 nanosheets, but these polymers have very low thermal conductivity and cannot improve the PbI 2 Photostability

Method used

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  • Method for improving light stability and fluorescence intensity of two-dimensional lead iodide
  • Method for improving light stability and fluorescence intensity of two-dimensional lead iodide
  • Method for improving light stability and fluorescence intensity of two-dimensional lead iodide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Example 1 Preparation of zinc oxide / lead iodide nano-heterojunction

[0023] 1. PbI 2 Synthesis of Nanosheets

[0024] PbI was synthesized by dissolution and recrystallization 2 Nanosheet; the specific operation is as follows:

[0025] 1) PbI with a purity of 99.9% 2 The powder was dissolved in secondary deionized water to prepare a 1mg / mL solution, heated and stirred at 110°C until completely dissolved to obtain PbI 2 aqueous solution;

[0026] 2) Place PbI at room temperature2 One hour after the aqueous solution, use a high-precision pipette to draw 50 μL of the solution, and drop it on the cleaned SiO 2 / Si substrate (1cm×1cm), after 5-10 minutes, suck out the excess liquid with a straw to obtain PbI with different sizes, shapes, and thicknesses. 2 Nanosheets;

[0027] 2. Synthesis of ZnO nanowires

[0028] ZnO nanowires were prepared using a typical hydrothermal method, the specific operation is as follows:

[0029] 1) Dissolve zinc acetate and hexamethylen...

Embodiment 2

[0033] Example 2 Characterization and detection of lead iodide nanosheets

[0034] Our analysis of the prepared PbI 2 The nanosheets were subjected to PL and Raman spectroscopy measurements to further characterize PbI at different thicknesses 2 Properties of nanosheets at room temperature; figure 1 (a), as the thickness decreases from 553 nm to 12 nm, the PbI 2 The intensity of the PL peak around 510nm gradually weakens. With PbI 2 As the nanosheet becomes thinner, the light absorption decreases, and the PL quantum efficiency also decreases. At the same time, as the thickness becomes thinner to the monolayer, the energy bandgap changes from direct to indirect. Unlike the PL spectrum, PbI 2 The Raman spectrum is too weak at room temperature to be identified, so the excitation power must be increased to irradiate PbI 2 slices to obtain observable Raman signals. Due to PbI 2 The photostability of nanosheets is poor, and high excitation power inevitably damages their cryst...

Embodiment 3

[0035] Example 3 ZnO / PbI nano-heterojunction effect experiment

[0036] 1. Laser irradiation experiment

[0037] PB 2 An important property that the protective layer needs to have is high light transmittance to ensure that the photon absorption of the protective layer is minimized; the absorption edge of the ZnO nanowire is located at about 380nm, while the PbI 2 The absorption edge of the nanosheets is located at around 520nm; obviously, the wider forbidden band width of ZnO can be PbI 2 Provides an ideal photon absorption window in the near UV and visible light. On the theoretical basis, we carried out corresponding irradiation experiments to verify the effect of ZnO nanowires on PbI 2 The protective effect, as shown below; respectively for the non-covered PbI 2 Nanosheets and ZnO / PbI 2 The heterojunction is irradiated with variable power laser, and then the PL spectrum of the irradiated sample is collected using an excitation light source of uniform power. Both the ir...

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Abstract

The invention discloses a method for improving the stability and photoluminescence intensity of two-dimensional lead iodide, and the method comprises the following steps: 1) dissolving PbI2 powder in secondary deionized water, performing heating and stirring until the PbI2 powder is completely dissolved to obtain a PbI2 aqueous solution, placing the PbI2 aqueous solution at room temperature, sucking 50 [mu]L of the solution, and dropping the solution on a SiO2 / Si substrate to obtain a PbI2 nanosheet; 2) respectively dissolving zinc acetate and hexamethylenetetramine (HMT) in water, and performing full stirring and mixing to obtain a ZnO precursor solution, pouring the solution into a reaction kettle, putting a sapphire substrate with the front surface facing downwards, and performing heating to obtain ZnO nanowires; 3) obtaining a zinc oxide / lead iodide nano heterojunction by using a PDMS assisted drying transfer technology; due to the fact that the heterojunction forms I-type energy band arrangement, photo-induced electrons and holes can be transferred from ZnO to PbI2; not only is a new feasible strategy provided for improving the photostability and photoluminescence of PbI2, but also the negative influence of the protective layer on the photoluminescence of PbI2 is minimized, and the remarkable enhancement of the photoluminescence of PbI2 is obtained.

Description

technical field [0001] The invention belongs to the technical field of nanostructure performance improvement, and specifically relates to a method for improving the photostability and fluorescence intensity of two-dimensional lead iodide. Background technique [0002] Since the discovery of graphene, two-dimensional (2D) materials have attracted extensive attention and applications in fundamental sciences and fields such as electronics, valleytronics, optoelectronics, and sensors due to their unique physical and chemical properties. In addition to graphene, there are many semiconductor or insulating materials in the 2D material family, such as hexagonal boron nitride (h-BN), black phosphorus (BP), transition metal oxides (TMOs), transition metal dichalcogenides ( TMDs) etc. Among them, TMDs materials have rich optoelectronic and optical properties and have been extensively studied in optoelectronic devices in the past decade. However, the bandgap type of TMDs is quite sens...

Claims

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Application Information

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IPC IPC(8): C09K11/02C09K11/66
CPCC09K11/664C09K11/025
Inventor 李远征刘为振李济修徐海阳刘益春
Owner NORTHEAST NORMAL UNIVERSITY
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