Atomic, Molecular and Optical Data requirements for lighting

1. Atomic, Molecular and Optical Data requirements for lighting 20th ESCAMPIG, Novi Sad, July 13 – 17, 2010 Nigel Mason The Open University UK

2. Workshop on data needs for lighting • Session to discuss fundamental processes involved in development of lighting • Discuss data we have and what we don’t know. • and comment on the use of DATA BASES

3. VAMDC is funded under the “Combination of Collaborative Projects and Coordination and Support Actions” Funding Scheme of The Seventh Framework Program. Call topic: INFRA-2008-1.2.2 Scientific Data Infrastructure. Grant Agreement number: 239108.

4. VAMDC will provide a scientific data e-infrastructure enabling easy access to A+M resources VAMDC is funded under the “Combination of Collaborative Projects and Coordination and Support Actions” Funding Scheme of The Seventh Framework Program. • Http://www.vamdc.org/

5. VAMDC does not collect or commission data but… Will be a ‘one stop shop’ access to databases (currently some 17 are planned) Wants to know what data is needed and the format it is most usefully presented in ; hence supports these meetings and discussions WHAT DO YOU NEED ? Survey will follow this meeting !

6. Some introductory remarks • Lighting devices are one of the traditional areas of low-temperature plasma applications. • Gas discharges used in lighting devices (fluorescent lamps, barrier discharge lamps, flat panel displays, etc) cover a wide range of plasma parameters. High intensity discharge lamps are low temperature (0.5 eV or 5400 K), weakly ionized plasmas • Need to generate (380–780 nm) light so as to be comparable to natural sunlight.

7. Some introductory remarks • 7.5 billion lamps operate world-wide consuming 1,000 billion kWh per year (10-15% of the global energy production world-wide). • About 11% for France, 20% for US but 37% for Tunisia ! • Furthermore, the annual greenhouse gas (CO2) due to this energy production is estimated to be in the order 550 million tons • Lighting expected to increase three times worldwide (China, India) in this decade • World-wide turnover of the lighting industry more than 15 billion Euros.

8. Some introductory remarks • More efficient lighting is therefore an essential part of the ‘green economy’. More efficient light sources would • limit the rate-of-increase of electric power consumption • reduce the economic and social costs of constructing new generating capacity ; • reduce the emissions of greenhouse gases and other pollutants. • An improvement of 25% in the lamp efficacy corresponds to 750 billion kWh per year energy savings as well as 300,000 tons less greenhouse gas in the atmosphere.

9. Europe is banning the traditional tungsten light bulb in favour of

10. Data needs • An understanding of the chemistry, dynamics and radiative properties of such plasmas, is necessary to optimize such lighting devices • The most important of which are the lamp efficiency and lifetime • But this • relies on the knowledge of collisional and spectroscopic characteristics of all relevant plasma constituents

11. Data needs • Major sources are principally fluorescent lamps and metal halide discharge lamps • Rare earth metals are commonly used in metal halide lamps to provide a white light spectrum similar to that of natural light. • Three elements of interest are thullium, holmium and dysprosium. • These metals have very rich atomic spectra, with many thousands of lines throughout the visible region, but relatively little radiation in the ultraviolet and infrared regions. In many cases the atomic data for these elements are missing.

12. Data needs • Nor is atomic data alone sufficient… • The primary reason that molecules are of interest in HID lamps is that they transport useful metals into the vapour phase. • At lamp operating temperatures (900-1300 C) the vapour pressure of pure metals of interest is generally too low (<10-11 torr) to be of practical significance. • Metal salts have much higher vapor pressures and can function as useful mechanism for transporting metals into the arc [2]. Iodide salts are used for this purpose. • The transport of metal atoms via molecular parent molecules is an advantageous method for enhancing the metal content of the plasma, and is the reason why the certain HID lamps are called metal-halide lamps.

13. Data needs • Example • DyI3, At lamp operating temperature (1200K), dysprosium triiodide has a vapor pressure more than ten orders of magnitude higher than the pure metal. • Metal iodides such as InI, TlI are present • Metal iodides are very susceptible to moisture and react quickly if any residual water remains in the lamp after manufacturing • 2MI3 + 3H20 → M203+6HI • HI breaks down releasing Iodine • Hg + 2I → HgI2 or InI + 2I → InI3

14. These are not ‘normal’ molecules • InI, TlI HI • HgI2 • DyI3, InI3 • Spectroscopic data base incomplete • and electron collisions…. • often cant measure in laboratory !

15. Now series of short talks…then open discussion (any slides welcome)

16. International Symposium on the Science and Technology of Light Sources • And • International Conference on White LEDs and Solid State Lighting EINDHOVEN, THE NETHERLANDS, JULY 11-16, 2010

17. Image 1 of 122 • Good time had be all… but hot

18. The Talks • Mikhail BenilovUniversity of Madeira, Portugal • Ursel Fantz, University of Augsburg, Germany • Bratislav Marinkovic, Institute of Physics Belgrade, Serbia • John Curry, NIST, USA