Preparation method of graphene thin film field emission material

[0025] Example 1

[0026] The device is attached figure 2 b, the stainless steel plate 1 is connected to the positive electrode of the power supply, the ITO glass 3 is connected to the negative electrode of the power supply, the graphene solution 2 is placed in a polymethyl methacrylate (PMMA) plastic container 4, and the stainless steel plate 1 and the ITO glass 3 are respectively inserted into the graphene solution 2 in.

[0027] The lateral dimension prepared by chemical peeling method is 500nm~1μm, the number of layers is 1~3 (thickness is about 0.8~2.3nm), and the conductivity is 1×10 3 S/cm graphene as raw material, graphene and Mg(NO 3 ) 2 It was added to the low-polarity organic solvent isopropanol (IPA) at a weight ratio of 1:1, and the concentration of graphene was 0.1 mg·mL -1 , ultrasonically dispersed at room temperature for 1 h to obtain a uniform and stable graphene suspension; a polished stainless steel plate was used as the positive electrode (5 cm × 2 cm × 2 mm), and a conductive glass (2 cm × 2 cm) was covered with an indium tin oxide (ITO) coating with a thickness of 100 μm 1 cm × 2 mm) as the negative electrode, the distance between the positive and negative electrodes is 5 mm, the operating voltage is 160 V, and the electrophoretic deposition time is 1 min, and a graphene film with a thickness of about 0.5 μm is prepared; the electrophoretic deposition film (1 cm × 1 cm × 2 mm) is used as The cold cathode material was tested in an ultra-high vacuum spherical chamber field emission performance test system with a vacuum degree of 10 -5 Pa, the anode is a cylindrical (iron) needle tip with a diameter of 1 mm, and the distance between the positive and negative electrodes is kept at 100 μm.

[0028] The test results show that the turn-on electric field and threshold of the graphene film field emission material are 2.3V·μm, respectively. -1 and 5.2V μm -1 , the enhancement factor is ~3700 at 11.46 mA cm -2 The decay at 12 hours at an initial current density of ∼4%.

[0029] Example 2

[0030] The device is attached figure 2 b.

[0031] The lateral dimension prepared by chemical peeling method is 500nm~1μm, the number of layers is 1~3 (thickness is about 0.8~2.3nm), and the conductivity is 1×103 S/cm graphene as raw material, graphene and Mg(NO 3 ) 2 It was added to the low-polarity organic solvent isopropanol (IPA) at a weight ratio of 2:1, and the concentration of graphene was 0.2 mg·mL -1 , ultrasonically dispersed at room temperature for 2 h to obtain a uniform and stable graphene suspension; a polished stainless steel plate was used as the positive electrode (5 cm × 2 cm × 2 mm), and a conductive glass (2 cm × 1 cm × 2 mm) as the negative electrode, the distance between the positive and negative electrodes is 10 mm, the operating voltage is 150 V, and the electrophoretic deposition time is 2 min to prepare a graphene film with a thickness of about 1 μm; the electrophoretic deposition film (1 cm × 1 cm × 2 mm) is used as a cold Cathode materials were tested in an ultra-high vacuum spherical chamber field emission performance test system with a vacuum degree of 10 -6 Pa, the anode is a cylindrical (iron) needle tip with a diameter of 1 mm, and the distance between the positive and negative electrodes is kept at 50 μm.

[0032] The test results show that the turn-on electric field and threshold of the graphene film field emission material are 1.2V·μm, respectively. -1 and 3.3V μm -1 , the enhancement factor is ~4000 at 12 mA cm -2 The decay at 12 hours at an initial current density of ∼2%.

[0033] Example 3

[0034] The device is attached figure 2 b.

[0035] The lateral dimension prepared by chemical peeling method is 500nm~1μm, the number of layers is 1~3 (thickness is about 0.8~2.3nm), and the conductivity is 1×10 3 S/cm graphene as raw material, graphene and MgCl 2 It was added to the low-polarity organic solvent dimethylformamide (DMF) at a weight ratio of 1:1, and the concentration of graphene was 0.1 mg·mL -1 , ultrasonic dispersion at room temperature for 1 h to obtain a uniform and stable graphene suspension; a polished stainless steel plate is used as the positive electrode (5 cm × 2 cm × 2 mm), and a conductive glass (2 cm × 1 cm) is covered with an indium tin oxide (ITO) coating with a thickness of 200 μm. ×2mm) is the negative electrode, the distance between the positive and negative electrodes is 5mm, the operating voltage is 100V, the electrophoretic deposition time is 2min, and a graphene film with a thickness of about 0.5 μm is prepared; Cathode materials were tested in an ultra-high vacuum spherical chamber field emission performance test system with a vacuum degree of 10 -6 Pa, the anode is a cylindrical (iron) needle tip with a diameter of 1 mm, and the distance between the positive and negative electrodes is kept at 100 μm.

[0036] The test results show that the turn-on electric field and threshold of the graphene film field emission material are ~2.0V·μm, respectively. -1 and ~5.1V μm -1 , the enhancement factor is ~3800 at 12 mA cm -2 The decay at 12 hours at an initial current density of ∼4%.