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

研究了纯水、几种水溶液和碳氢化合物等液体介质中等离子体的放电和光发射特性。为了进行这些调查，我们已经构建了以下放电装置：液体电极的介质阻挡放电系统，红树林型阻挡放电系统，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，讨论了这些等离子体作为发光器件的可能性。在水面放电中，当我们除了空气之外还使用氩气或氦气作为放电气体时，已经获得了足够的可见发光。我们还发现，对水的强烈放电可以分解水中的有机化合物，OH自由基似乎是负责分解。如果t ...更多信息 在充水管道中漂浮的单个气泡放电中，我们只在使用含有金属颗粒的水时才获得气泡放电。当气泡位于金属表面时，气泡中放电的点火变得更容易。我们采用了一种电解技术，在金属表面产生并固定气泡，而不向水中通入气体，并成功地获得了氢气或氧气气泡在电解电极上的放电，尽管其光发射目前还不够高。为了在不将气体供给到液体介质中的情况下获得气泡，我们还利用了覆盖有多孔介电膜的金属电极，在该多孔介电膜上在乙醇中施加高电压。在这种情况下，乙醇中的气泡通过焦耳加热产生。虽然我们不能观察到任何光发射的气泡漂浮在乙醇中，我们已经获得了放电和它的光发射的气泡之间的电介质膜和金属电极。总之，我们已经证明了几种可能的类型的放电与液体介质上或在液体介质中，虽然，在这个时刻，在这项工作中获得的光发射的强度是不够高，应用这种技术的发光器件。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