Effective Light Source
Development of Effective Cathode-Luminescent Light Source with Field Emission Cathode Made of Nanostructured Carbon Materials
Tech Area / Field
- NNE-MEC/Miscellaneous Energy Conversion/Non-Nuclear Energy
8 Project completed
Senior Project Manager
Komarkov D A
Moscow Institute of Physics and Technology, Russia, Moscow reg., Dolgoprudny
- Institute of Chemistry named after V.I.Nikitin, Academy of Sciences, Republic of Tajikistan, Tajikistan, Dushanbe
- University of New Orleans, USA, LA, New Orleans\nMER Corporation, USA, AZ, Tucson
Project summaryMain purpose of the project: creation of effective light sources with the efficiency up to 30%. The basis of developing cathodoluminescent light sources is the idea of using a field emission cathode made of nanostructured carbon materials in such sources.
Using field emission cathodes made of carbon materials, which provide for high electron field emission and high efficiency of transforming electric energy into the light during the cathodoluminescent process puts cathodoluminescent light sources in a raw of the most promising and competitive ones. Among the basic advantages of this method of getting light energy are operational reliability and high efficiency (up to 30%), durable service life, short time of switching. A field emission cathode does not require heating. It is non-inertial, easily resists the temperature oscillations and has high density of the emission current. Field emission cathodes made of nanostructured carbon are able to operate in the technical vacuum (~ 10-4 Pa) for quite a long time. They are much cheaper and more resistant than metallic and semi-conductor field emission cathodes, substantially easier bear the electric break-down.
A cathodoluminescent light source allows getting visible range radiation having the spectral composition comfortable for visual perception. It does not cause such eye fatigue as most known light sources do. Unfavorable and harmful infrared and ultraviolet radiation is absent in cathodoluminescent radiators.
Cathodoluminescent light sources with the field emission cathode do not include any poisonous materials and gases, which are harmful for human health. For such light sources there is no problem of manufacturing and utilizing used lamps connected with dangerous production and environmental pollution, which is typical for, e.g., luminescent lamps containing mercury vapors.
At present incandescent lamps (efficiency ~ 1%), mercury daylight lamps (efficiency ~ 10%) and some other are widely used for illumination. All of them have a lot of disadvantages. Main of these are low efficiency, poor ecology, low reliability, short service life, presence of harmful radiation and/or poisonous substances etc.
Only the discovery of nanostructural forms of carbon and their use in producing field emission cathodes of cathodoluminescent lamps allows raising the efficiency of transformed energy up to 30%. This is three times higher than the efficiency of “daylight lamps”. Stability and ecological safety distinguishes lamps with cold field emission cathodes from others, and their economical efficiency will make them the most popular light source in the nearest future. Introduction of the developed technology of manufacturing lamps in the mass production in future will give the threefold reduction of the energy consumption required for illumination.
Nevertheless, despite the success in creating field emission cathodes made of nanostructured carbon, electron-optical systems with such cathodes, which take into account the features of nanostructured cathode’s behavior in the process of its operation in a lamp under the influence of destructive factors, are not yet developed.
Basic difficulties in developing an electron-optical system with the field emission cathode are connected with the non-uniform spatial distribution of the electron flow from the cathode and change of emission centers’ location on the cathode under the influence of destructive factors. Besides, cathodoluminescent light source should have high electric strength and low probability of electric breakdowns of inter-electrodes’ gaps. The lamp’s electric strength, in turn, depends on both cathode processes and the processes occurring at the electrodes radiated by high-energy electrons.
To create an effective cathodoluminescent light source with the field emission cathode made of nanostructured carbon materials one should solve the following basic problems:
1. Developing the composition and the technology of manufacturing the field emission cathode made of nanostructured carbon with the optimal structure in order to provide for high self-restorability of the cathode’s emission centers under the influence of destructive factors – ion bombardment and ponderomotor loads.
2. Developing the regimes of the preliminary (atmosphere) and vacuum training of field emission cathodes aiming at the extraction of the internal skeleton structure of the cathode’s material with forming a dynamically balanced configuration of the emitting surface.
3. Studying the structural and emissive properties of field emission cathodes at different stages of its operation with the purpose of developing the method of forecasting serviceability of cathodes in cathodoluminescent light sources.
4. Developing the optimized electron-optical system with the field emission cathode made of nanostructured carbon, which provides for high coefficient of path of current flow (more than 90%) and minimally possible value of the control voltage (lower than 1000 V). Studying the influence of the dielectric envelope on the characteristics of the electron-optical system.
5. Developing the composition and the technology of manufacturing the luminescent anode, which provides for the high electric strength of the lamp and efficiency of transforming field emission electrons to the visible radiation.
The studies of the structural and emissive properties of carbon materials will be fulfilled with the use of atomic power, tunnel and scanning electron microscopy. Rather big efforts will be required to create the computer programs for the analysis and development of an effective electron-optical system for the light source with the field emission cathode made of nanostructured carbon.
It is planned that the development works will be completed with the creation of the method and the technology of producing cathodoluminescent lamps with the efficiency of 30% and the service life more than 10000 hours, which can operate in different weather conditions at the temperatures from -150 °C to +150 °C with the light efficiency ~ 26 lm/W and white light brightness 7000 - 12000 Cd/m2.
The proposed R&D program will be accomplished by the teams of scientists and specialists representing the institutes MIPT and IC ASRT of two countries – Russia and Tajikistan. They work successfully for many years in different fields of physics and chemistry of nanostructured materials and emission electronics, and are known internationally.
The role of the international collaborators in the represented project includes the joint preparation, discussion and correction of plans, intermediate and final results of the work, fulfillment of some joint R&D, help to the participants in marketing, possible further joint use of the developed technologies and operating prototypes of the cathodoluminescent light sources, e.g. introduction into the industrial scale manufacture.
The accomplishing of the project will allow achieving the following goals:
- will give to the scientists and specialists of Russia and Tajikistan, who are engaged in the military research, the possibility to re-orient their activities to non-military segment;
- will facilitate the integration of the Russian and Tajik scientists into the international scientific community;
- will make possible the effective use of the experimental and analytical basis of MIPT and IC ASRT;
- will support R&D of high-technology and ecological products.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.