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Hans U. Güdel Department für Chemie und Biochemie
Seminar Fribourg, 13.10.2009
Making light
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Making light
3
Area illuminators
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OLED Technology
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• Light• White and coloured light• Photoluminescence, phosphors• Spectrum• Light emitting diodes (LED) • Outlook
Making light
• Light
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• Light
Making light
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Fiat Lux
1 in principio creavit Deus caelum et terram
2 terra autem erat inanis et vacua et tenebrae super faciem abyssi et spiritus Dei ferebatur super aquas
3 dixitque Deus fiat lux et facta est lux
4 et vidit Deus lucem quod esset bona et divisit lucem ac tenebras
First Book Moses (Genesis), Chapter 1
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Black body radiation
Temperature: Colour:
2500°C
5000°C
7500°C
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Black body radiation
Temperature: Colour:
5000°C
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Human eye photoreceptors
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Incandescent lamp
2500°C
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Dispersion of white light
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Making light: Additive mixing
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Chromaticity Diagram
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Photoluminescence
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Kasha's Rule
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Light emitting semiconductor
Light emission
Conduction band
Valence band
+
–
Bandgap
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Photoluminescence of CdSe Nanoparticels
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Fluorescent lamp
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Luminescent phosphors
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Lamp and display phophors
BaMgAl10O17: Eu2+
(Ce,Gd)MgB5O10: Tb3+
Y2O3: Eu3+
Judith Grimm
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The Lanthanides
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Coloured light
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LED based technology
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Light emitting diodes (LED)
Electroluminescence
Conduction band
Valence band
+
–
Bandgap
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LED Materials
Inorganic
III – V Semiconductors
Al, Ga, In N, P, As, Sb
Al Ga As
Al Ga In P
Al Ga P
Ga N
Organic (OLED)
Polymeric luminescent molecules with conjugated electron systems
Polyphenylenvinylene
n
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Light emitting polymer
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Mirco Colombo citations, 3 papers
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Diode spectra
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White diode lamp
Y3Al2(AlO4)3: Ce3+ Diode
+
–
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Chromaticity Diagram
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Energy efficiency of light sources
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Light sources
Technology steps
Electronics
Tube
analog
Tube Diode
Solid
Micro electronics
digital, solid
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Area illuminators
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Acknowledgment
Gabriela Frei
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