Photoinduced thermoelectron emission source based on low work function composite nanomaterial and its preparation method

Abstract

The invention provides a photothermal electron emission source device based on a composite nanomaterial of combining a low work function thermal electron emission material film and a photothermal material capable of improving the electron emission efficiency of a photothermal electron emission source and a preparation method of the photothermal electron emission source device. The photothermal electron emission source comprises a cathode electrode, photoelectric conversion material layers prepared on the cathode electrode and low work function thermal electron emission material films covering the surfaces of the photoelectric conversion materials. The low work function thermal electron emission material films are combined with the photoelectric conversion materials, the excellent thermal electron emission performance of the low work function thermal electron emission material films is utilized and the excellent photothermal conversion efficiency of the materials, such as a carbon nanotube and noble metal nano-particles is also utilized, so that advantage complementation of the two materials is achieved through an indirect heating mode, and the technical disadvantages, such as high incident light power and low brightness required by an existing photothermal electron source are overcome.

Description

Technical field [0001] The invention relates to a photothermal emission cathode and a preparation method thereof, in particular to a photothermal electron emission cathode based on a low work function composite nano material, which is suitable for cathode electron sources in various vacuum electronic devices or vacuum solar devices . Background technique [0002] There are many forms of vacuum electron emission, such as thermionic emission, field electron emission, and photoelectron emission. In the photoelectron emission, there is a photothermal electron emission mechanism, which mainly uses materials to absorb light energy to generate high temperature, and then realize thermionic emission. Compared with the traditional thermionic source, this electron emission mechanism has the advantages of large emission current density, controllable emission area, fast response speed, and high sensitivity. Compared with the field-induced electron emission, which has been studied more at pre...

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Problems solved by technology

However, the work functions of these materials are relatively high, for example, the work function of carbon nanotubes is about 4.8eV, and that of gold is about 5.3eV, which limits the photothermal electron emission performance of these materials to some extent.

In contrast, some thin films of low work function thermionic emission materials, such as lanthanum hexaboride (LaB6, with a work function of about 2.5eV), have good thermionic emission capabilities, but their photothermal effects are relatively weak and difficult to realize. efficient photothermoelectron emission

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