1 MSc: f-Elements, Prof. J.-C. Bünzli, Lighting applications Chapter 5 Selected applications

2 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Producing white light: trichromatic stimuli There are three “prime” colors corresponding to the three spectral responses of human vision nm CRI / % nm Color rendering index obtained by mixing the three prime colors Eu III Tb III (Eu II ) Chapter 5 Selected applications

3 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 x y Trichromatic diagram Emission Reflectance Trichromatic stimuli Chapter 5 Selected applications

4 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Coating W filament VV Filling gas: Ar UV (254 nm) e-e- Hg UV photons excite phosphor-containing coating leading to a white emission thanks to an appropriate blend of phosphors (Courtesy of P. Ceintrey, Rhodia Electronics & Catalysis) Chapter 5 Selected applications

5 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 YearPhosphor 1960Ca 5 (PO 4 ) 3 Cl:Sb 3+,Mn 2+ (white) 1974BaMg 2 Al 16 O 27 :Eu 2+ CeMgAl 10 O 19 :Tb 3+ Y 2 O 3 :Eu BaMgAl 10 O 17 :Eu 2+ (Sr,Ca) 5 (PO 4 ) 3 Cl:Eu 2+ (La,Ce)PO 4 :Tb 3+ CeMgAl 10 O 19 :Tb 3+ (Gd,Ce)MgB 5 O 10 :Tb 3+ Y 2 O 3 :Eu BaMgAl 10 O 17 :Eu 2+ (La,Ce)PO 4 :Tb 3+ Y 2 O 3 :Eu 3+ Major phosphors used by lighting industry Chapter 5 Selected applications

6 MSc: f-Elements, Prof. J.-C. Bünzli, D0→7F15D0→7F1 LMCT f-f transitions Absorption spectrum Y 2 O 3 features metal ion sites with O h symmetry, e.d. transitions are therefore forbidden /nm Emission spectrum Y 2 O 3 :Eu 3+ Hg 254 nm Chapter 5 Selected applications

7 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 LaPO 4 : Ce,Tb (nm) Absorption spectrum 4f-5d transition Emission spectrum Hg 254 nm Ce 3+ → Tb 3+ transfer Chapter 5 Selected applications

8 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Synthesis Main difficulty is to reach adequate particle size Example: red phosphor (Courtesy of P. Ceintrey, Rhodia Electronics & Catalysis) 2  m Volume (%) Particle diameter /µm 2.68  m Chapter 5 Selected applications

9 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Green phosphor is obtained by co-precipitation leading to incorporation of Ce 3+ and Tb 3+ in the LaPO 4 lattice; allows control of morphology, particle size and oxidation state of Ce and Tb. (Courtesy of P. Ceintrey, Rhodia Electronics & Catalysis) After flux addition Precursor 10  m 3  m Chapter 5 Selected applications

10 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Blue phosphor Sr 4 Al 4 O 25 :Eu II nm excitation Emission (d-f transition) Hg 254 nm Chapter 5 Selected applications

11 MSc: f-Elements, Prof. J.-C. Bünzli, P /  W·nm -1 ·lm -1 J.M.P.J. Verstegen et al., J. Electrochem. Soc. 1974, 121, 1627 Spectral distribution of a luminescent lamp with the following phosphors: BaMg 2 Al 16 O 27 :Eu II CeMgAl 11 O 19 :Tb III Y 2 O 3 :Eu III Chapter 5 Selected applications

12 MSc: f-Elements, Prof. J.-C. Bünzli, Fluorescent lamp Incandescent lamp Light Emitting Diodes * Heat loss: 100 W gives only 18 W for lighting * Elimination of heat loss but * 55% of energy is lost during conversion of UV excitation into visible photons Energy saving * 35% of energy is lost during conversion of UV excitation into visible photons The future of lighting (Courtesy of P. Ceintrey, Rhodia Electronics & Catalysis) 18 % % % Chapter 5 Selected applications

13 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Eliminating mercury from lamps: quantum cutting 6 G J 6 P J 8 S 7/2 7 F J a a 5 D J Eu Gd b b  200 nm Ar discharge 190 nm Chapter 5 Selected applications

14 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 UV 5.5Security inks Euro bills Chapter 5 Selected applications

15 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 The euro is protected by the luminescence from europium: red from Eu III Europium was discovered by Eugène A. Demarçay in 1901 in Paris / nm 5 D 0 7 F J Eu III 2 J = Chapter 5 Selected applications nm exc

16 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 exc = 375 nm /nm Possibly Eu II ? Chapter 5 Selected applications

17 MSc: f-Elements, Prof. J.-C. Bünzli, Luminescent chemical sensors The specific spectroscopic properties of Ln III ions make them ideal luminescent probes: - easily recognizable line-like spectra - long lifetimes of excited states - large Stokes’ shift upon ligand excitation Time-resolved luminescence allows high signal-to-noise ratios, henceforth high sensitivity Lanthanide-containing luminescent probes can be used as: - structural probe (site symmetry) - analytical probes (mainly for bio-analyses) - imaging probe for medical diagnosis (tumor imaging) Chapter 5 Selected applications

18 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Time-resolved luminescence: an essential tool Detection limits Ionl exc  /10 3 l em /nm  /  sQDet. lim. Eu pM Sm pM UV pulse 2-4 ms Background luminescence Eu emission measurement time I em Chapter 5 Selected applications

19 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Ln III luminescence as signaling method h h h h an + a) Direct binding of the analyte modifies the Ln III inner co-ordination sphere Here, water molecules are expelled, lifting the luminescence quenching. Chapter 5 Selected applications J.-C. Bünzli & C. Piguet, Chem. Soc. Rev. 2005, 34, 1048

20 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 an h h b) Binding of the analyte to a ligand modifies its energy- transfer properties Here, binding of the analyte results in a quenching of the metal-centered luminescence. Alternatively, luminescence can be activated by such a binding. Chapter 5 Selected applications

21 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 an h h h h c) Binding of the analyte to a ligand initiates an energy- transfer process to the metal ion Note: in bio-analyses, specific biochemical reactions are usually used to render the analysis target specific. Chapter 5 Selected applications

22 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 a) Modification of inner coordination sphere: anion analysis NN NN P O Eu OTf 2 OH 2 In acetonitrile: Q = 2.6 %  = 0.86 ms NN NN P O Eu O OTf 2 O O N Q = 30 %  = 1.45 ms K assoc = 10 6 L. J. Charbonnière et al., J. Am. Chem. Soc. 2002, 124, 7779 OTf = CF 3 SO 3 - Chapter 5 Selected applications

23 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Supramolecular pH sensor D. Parker et al, J. Am. Chem. Soc. 2001, 123, 7601 pH sensor H3O+H3O+ (H 2 O) -H 3 O + modulates electron density of N-atom pH range 5 – 7.5 Chapter 5 Selected applications

24 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Eu III Luminescence Supramolecular pH sensor Chapter 2 Physico-chemical properties

25 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 electronic relays A.P. de Silva et al., Chem. Commun. 1997, 1891 Ln binding unitEu logK = 4.8 (MeOH ) b) Removal of a quenching process O O N OO O O O N OO O O O N OO O K + receptor Chapter 5 Selected applications O O N OO O O O N OO O O O N OO O K + receptor

26 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 A.P. de Silva et al., Chem. Commun. 1997, 1891 UV-irradiation Eu III Eu II Luminescence quenched by PET process Q = 2.6% in MeOH O O N O O O NN N N O O OO O OMeO O OMe Eu O O N O O O NN N N O O OO O OMeO O OMe Chapter 5 Selected applications

27 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 K K Eu UV-irradiation light emission Q = 47 % in MeOH logK = 4.3 (MeOH) A.P. de Silva et al., Chem. Commun. 1997, 1891 Chapter 5 Selected applications

28 MSc: f-Elements, Prof. J.-C. Bünzli, 2008  -CD coupled to dtpa weak Tb emission in H 2 O Strong Tb emission in H 2 O due to efficient energy transfer from host Nocera et al., Coord. Chem. Rev. 1998, 171, 115 Tb N O N N N O N O O O O O H H OH 2 2 c) Initiating an energy transfer process Tb N O N N N O N O O O O O H H OH 2 2 Chapter 5 Selected applications

29 MSc: f-Elements, Prof. J.-C. Bünzli, c / ppm I rel Supramolecular PAH sensor Tb luminescence enhancement Tb N O N N N O N O O O O O H H OH 2 2 Chapter 5 Selected applications

30 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 k isc = 5.2·10 8 s -1 k et = 8.3·10 4 s -1 E / 10 3 cm S0S0S0S0 S1S1S1S1 3T3T3T3T Tb 3+ 5D45D4 7FJ7FJ k r = 1.7·10 4 s -1 Nocera et al., Coord. Chem. Rev. 1998, 171, 115 Supramolecular PAH sensor Tb N O N N N O N O O O O O H H OH 2 2 Chapter 5 Selected applications

31 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Supramolecular PAH sensor (2) Enhancement of the Tb luminescence in de-oxygenated solution by supramolecular fixation of naphtalene D. Parker et al., J. C. S., Perkin Trans. 2, 2000, 1329 Large association constant: logK = 4 permethylated  -CD sensitised Tb 3+ emission Chapter 5 Selected applications

32 MSc: f-Elements, Prof. J.-C. Bünzli, 2008 Supramolecular PAH sensor (2) c -1 / 10 4 M -1 (I - I 0 ) -1 Benesi-Hildebrand analysis logK napht = 4 D. Parker et al., J. C. S., Perkin Trans. 2, 2000, 1329 Chapter 5 Selected applications