Generation of plasmas in liquid media and its application to light emitting devices

我们研究了等离子体在纯水、几种水溶液和碳氢化合物等液体介质中的放电和光发射特性。为了进行这些研究，我们构建了以下放电装置：液体电极的介质阻挡放电系统、红树林类型的阻挡放电系统、单泡放电系统、水电解-气泡放电系统和多孔介质覆盖的金属电极系统。在此基础上，我们讨论了这些等离子体作为发光器件的可能性。在水面上的放电中，除了空气外，当我们使用Ar或He作为放电气体时，已经获得了足够的可见发光。我们还发现，水中强烈的放电可以分解水中的有机化合物，而OH自由基似乎是导致分解的原因。在测试…的情况下在充水管道中漂浮的单个气泡中放电更多，只有当我们使用含有金属颗粒的水时，才能在气泡中获得放电。当气泡在金属表面时，气泡中放电的着火变得更容易。我们采用了一种不向水中通入气体的电解技术在金属表面产生和固定气泡，并成功地在电解电极上实现了氢气泡或氧气泡的放电，尽管目前其光发射还不够高。为了在不将气体送入液体介质的情况下获得气泡，我们还使用了覆盖有多孔介电膜的金属电极，在乙醇中施加高压。在这种情况下，乙醇中的气泡是通过焦耳加热产生的。虽然我们没有从漂浮在乙醇中的气泡中观察到任何光发射，但我们已经在介质膜和金属电极之间的气泡中获得了放电及其光发射。总而言之，我们已经证明了几种可能的放电类型，无论是在液体介质上还是在液体介质中，尽管目前在这项工作中获得的光发射的强度还不够高，不足以将这项技术应用于发光设备。较少

We have investigated characteristics of the electrical discharge and optical emission of the plasmas in/on/with liquid media such as pure water, several aqueous solution and hydrocarbons. In order to perform these investigations, we have constructed following electrical discharge devices ; dielectric barrier discharge systems with liquid electrodes, mangrove-type barrier discharge systems, single-bubble discharge systems, water-electrolysis-bubble discharge systems and porous-dielectric-covered metal electrode systems. On the basis of the characteristics obtained, we have discussed possibility of these plasmas as light emitting devices. In electrical discharge on the water surface, sufficient visible luminescence has been obtained when we employ argon or helium for discharge gases in addition to the air. We have also found that the intense discharge on the water can decompose organic compounds in the water, and that OH radicals seem to be responsible for the decomposition. In case of t … More he discharge in the single bubble floating in a water-filled tube, we have obtained electrical discharge in the bubble only when we employ the water which includes metal particles. Ignition of discharge in the bubble has become easier when the bubbles are on metal surface. We have employed an electrolysis technique for generating and fixing the bubbles on metal surface without feeding gases into the water, and have successfully obtained discharge in hydrogen or oxygen bubbles on the electrolysis electrode although its optical emission is not high enough at present. In order to obtain gas bubbles without feeding gases into a liquid medium, we have also utilized a metal electrode covered with a porous dielectric film on which high voltage is applied in the ethanol. The bubbles in the ethanol have been generated by Joule heating in this case. Although we cannot observe any optical emission from the bubbles floating in the ethanol, we have obtained discharge and its optical emission in the bubbles between the dielectric film and the metal electrode. In summary, we have demonstrated several possible types of electrical discharge with, on or in liquid media, although, at this moment, intensity of the optical emission obtained in this work is not high enough to apply this technique to light emitting devices. Less