Chapter 3 Inorganic nanostructures in telecommunications 3.1 transparent conducting oxide electrodes (TCO) 3.2 electrochromy 3.3 electroluminescence (OLED, nano-based LED) 3.4 planar waveguides and NIR amplifiers in photonic circuits 3.1 transparent conducting oxides TCOs Introduction Figure of merit ~ T/R t R =p = 1/ eN|i R: lateral resistivity p: resistivity N: free carrier concentration |i: carrier mobility t: thickness e: elementary charge T: optical transmission Desired parameters: T (400-1200 nm)>80% Eg > 3 eV N ~ 1020 - 1021 cm-3 |i> 100 cm2 V-1 s-1 t ~ 500 nm -1 |im p< 10"4Qcm R < 2 Q sq/1 (t = 500 nm) Application domaines: Photovoltaics (CdTe, Si, CIGS) Telecommunication (LCD, OLED, electrochromy) Smart windows cavity 1. Control of N: doping! 2. Control of \i: morphology! 3. Optical gap : oxides! i* io2(N . * . ■. y. 11 ■ * . i ^... i '■ * ■ » *»» Bi 10*O' cm i i i 111 n| i i i 11»n| 0.1 1 10 X ft : %% >>N SJ % ^ GaAs 100 1000 Electron Mobility, (cmW1) /.. Spanhel Profile spectrale de transmission optique \ > i Miii—i—i—i—i r T-1—I-1—r ——j— IrijO^iSn n+=l iiowcm_a-| 0.3 O.S 400 900 600 700 wavelength (nm) J......1_I_I_I_■ l....._I_I_1_L 2 3 5 10 Wavelength (pml 20 30 50 L. Spanhel Elaboration of thin film electrodes Pulsed Laser Deposition Rf-magnetron sputtering L. Spanhel Contineous Elaboration of TCO TMA-OH 90ÔC 1 AI-(OC4H9)3 ' .& ^ Dip coating N2/H2 - sintering 3500 2500 1500 v [cm1] 500 fimm Mm-:: /.. Spanhel 0.001 cm2/Vs 100 80 60 1- 40 20 0 R = 17 Q/D 2 |im Film 0.5 1.0 1.5 2.0 2.5 Mpm] L. Spanhel ISAM = "ionic self-assembled monolayer", Chem. Phys. Lett. 1998, 298, 315 HAuCI^NaBH4/H20/PDDA > Sol: AuiPDDA size: 3-6 nm Spin-on O O O Q Q Q washing & deposition of Poly s-119 12 times repeated coatings Ch^ ci- (Aldrich) \......°* PDDA CH, {-H.O-C-)- NH I SO, Poly s-119 (Sigma) s Na+ O thickness : 50 nm R = 10"6Qcm 3.2 Chromatic materials Principle of chromaticism AT : thermochromy E : electrochromy hv: photochromy H2/02: gasochromy Electrochromy Basic principle Coloration in reversible redox process Ox uncolored Red colored CE (X) = n = A O.D. (X) IQ [cm2 C1] CE = coloration efficiency O.D. = optical density Q = charge transfered per cm2 L. Spanhel Intense Blue Pale Blue 400 450 500 550 600 650 700 Wavelength (nm) L. Spanhel Catodic Coloration: W035 Mo035 V2055 Nb2055 Ti025 Cu20 colored W03 + ne- + n M+ <- MnW03 w6+-o2--w6+ W6+-02"-H+(W5+) Anodic Coloration: NiO, CoO, Cu20, Ir02 colored Ni(OH): NiOOH + H+ + e- NiO + Ni(OH)2 Ni203 + 2H+ + 2 e" cathode Ui c 0 BC WO- BV BC NiO BV anode IHI L. Spanhel Electrochromic cells 1 - 4 V during 1- 5 minutes Good conductor (ionic/electronic!) Life time: 10.000 -100.000 cycles (5-20 years) Ionic conductors Gels, membranes: - Zr02, Ta205 - organosiloxanes - org. polymers: PEO, PVA Catodic Coloration Anodic Coloration + - IHI Catodic Coloration with propulsion I ITO 0 W03 ou Ti02/MV2< electrolyte I- '3* Li ITO L. Spanhel 3.3 Photo- and electroluminescence of semiconductor nanoparticles Application domains: 1. Bio-imaging systems 2. Electroluminescence (displays) 3. Photonic circuits: amplifiers (LASER) L. Spanhel "core/shell" nanostructures L. Spanhel Wavelength, i>im 1.2 1.7 U 0,* 07 Er>ergy, eV Figure 1 Representative room temperature PL (a) and absorptii spectra of DT-capped HgTe XCs in CCI4. The insets show tin dependence of the PL peaks, with the corresponding quantum effici (a) and illustrate the phase transfer completeness for MEA used as stabilizer (b)_ 9984 J. Phys. Chem. B, Vol. 106, No. 39, 2002 Energy (eV) 5.00 3.00 2.00 1.50 1.25 c c CD j s 600 800 1000 A/avelength (rim) L. Spanhel PEG-ZnO nanocomposites X. Yu et al. J. Lumin. 2006 + Electroluminescence (inverse photovoltaic effect) a cathode p-n diode D-A Ox-Red © anode ELE = n = P, IP. light,out1 1 el,in ELE = electroluminescence efficiency o a LUMO< .HOMO Anode Emitter Cathode Q LUMO. -1 „HOMO 1 f 1 Anode HTL Emitter ETL Cathode /.. Spanhel Cellule electrochimique d'ecran electroluminescente Principe de fonctionnement Couche entre 2 electrodes p+ anode ■ _____:_____■______ Luminophores ^^^^^^^ r e- cathode Systemes ä plusieurs couches Cathode Cathode Cathode ETM n-t>|)e Emitter ETM Emitter p-typc Emitter Emitter HTM HTM Anode A no lie Anode Anode a b. c d Molecules actives d'OLED N ^ o R R iS// PEDOT 1. Alaq3 = aluminium tris(8-hydroxyquinoline) 2. PPV = poly(p-phenylene-vinylene) 3. PPP = poly(1,4-phenylene) 4. PTh = polythiophenes 5. PF = polyfluorenes Poly-(3,4-ethylenedioxythiphene) i L. Spanhel Les systemes polymeriques ä doubles liaisons conjuguees PPV = poly(phenylene-vinylene) Eg = 2,5 eV emission jaune-vert Energie E, — — bände den ergie Le gap augmente quand L diminue orbitales a nti Mantes ■ orbitales ™ Mantes Nombre d'atomes L. Spanhel Dopage des semi-conducteurs organiques chimique ou electrochimique Oxydation trous positifs semi-conducteur' p ' (CH)X + xy(1,5l2) [CH^I3-)J yJx I- ^ Reduction -► electrons _► semi-conducteur 'n' (CH)X + xyL\+ +xye- [(Lh)v(CH)r]} La conductivite passe de 1fr5 ä 103 S/cm 41, L. Spanhel Electroluminescence avec nanostructures semi-conductrices « Band gap engineering » avec nanocristaux quantiques Taille moyenne: 3 nm - 10 nm d QJ □ ra +^ u QJ Q. co cd sz ec cd 4 - 3 - 2 1 - 0 - Semiconductor ; y y I ; 1 Semi-mete I - - ■n W \- < tfi Ul t- < c rj x3 ~d cd (fl dj c3) C — go jO 00 i— C go s= j2i j3 NJ N N /.. Spanhel Electroluminescence in nanocrystalline bilayers [AI3+@ZnO / Mn2+@ZnS - Znl2/ Al] Znl2(TBP)2-infiltré Standard Glass- to-Glass Gl3ss Lid Seal Glass substrate Desfeeant OL ED Thin Film Encapsulated on Plastic Thin film encapsulation —^ — Plastic or metallic substrate ^OLED Multilayer bamer coating IUI ^1 ITO verre 11 i ^LM 9 i. :. A & £. H * £ ! S. 0\ 1 I'.v. /.111.-1,, UNIVERSAL DISPLAY CORPORATION 1 SwX. Miniaturized plastic TV (180000 pixel, at present 500000pixel) IHI /.. Spanhel 3.4 Photonic nanomaterials Photonics = Science of light production, guiding and manipulation of light formation and treatment of images Photonic cavities Photonic crystals ► Amplifiers Nonlinear optics Holography Waveguides (passive, active) Coupling methods: a) 2 ßo ßi e) p / emitting —*-layer V////// substrate laser diode b) V \ --An n2 d) Fig. 213: Methods of optical coupling by means of: (a) a lens; (b) end-butt coupling; (c) prism; (d) grating; (e) tapered coupler; (0 coupling by optical tunneling. Descartes rules: 1. Total reflection ^film > ^substrat' ^air 2. Number of guided modes - m e mcc—n Ä film Jft L. Spanhel Propagation losses Damping coefficient: kA [dB cm-1] 10 x cm ]=^OD = 10, I0 x I Optical Absorption : In10 10 kA[dBcmA] Light scattering in composites: D.O. = 0,325 ®pxRlj r n particule -1 V matrix J IHI L. Spanhel Fabry-Perot coatings dielectrique Ti02 miroir Ag Depot des couches minces via "sputtering" Source: St. Gobain Herve Arribart UV-vis TL = 29 % RL = 65% —Glass/Ag (20 nm) Glassm02 (30 nmJ^Ag 3ÜÖ BOO 130Ö Wavelength ■ 3 -I—h 4— i t X Sol-gel derived nanomaterials: Bragg reflection produced in alternate Si02, Ti02 multilayers Microcavity composed of nanocrystalline Zr02 with 10% CdSe Micro cavity strongly doped with CdSe nanocrystals S. Rahaste1, J. BaUasaa1:11, C. Bonnand1, J.C. Planet1, and L. Spaniel2 1 Laboratoire de Physique de la Matiere Condenses et dee Nano3lru.etu.iies, Uni^ersite Claude Bernard Lyon 1, CNRS-UMR 42 boulevard dull Novembre, 65622 ViUjanrbanrua Cedex, France IHI L. Spanhel Light amplifiers in the NIR regime based on Er3+- doped matrix Dispersion Recovery ^ ( client 4'l3/2 1.5 |im 4"i 5/2 Er3+ /^~~y==r£&h* Signal ■-^jW'WDM /y Slgnal Pumpstralil^^^^^ ^^^J/ microchip today tomorrow /.. Spanhel Critical parameters: 1. N = 1020 - 1021 Er3+/cm3 2. Mean life time of fluorescence (ms !) 4 Phonon relaxation 'l1/2 C_; 13/2 15/2 Er-O- Er MxFy OH ö 1.54 fim D Quantum yield of fluorescence Dexter energy transfer T| = Wr+Wnr Wr+AeBp p = phonon = lattice vibration p = A E/ fi (jo = 6537 cnr1/ fi w L. Spanhel p = A E/ Ti co = 6537 cmV Ti w HCH R I / _ Vibration neu (cm1) p -phonons 0-H 3000-3500 2 C-H 2800 2-3 P-O-P 1300 5 Si-O-Si 1000 6 MxOy MxChalcy 300-800 8-20 fluoru res des métaux 200-400 15-30 (Er - F-Zr^F L. Spanhel Er3+ non-agrégé Absence des vibrations OH,CH Multifononová relaxace ve fotoexcitovaných etanolických nanokoloidech i 1400 1500 1600 1700 X[nm] L. Spanhel „co-dopovani" nanocastic ve 2M etanolickem solu ZnO Er:ZnO synthesis Er3+ Si(OEt)4 5 nm Zn(OAc)2 in 1-Propanol Me4N-OH 5-10% TEO§ 1-10 at.% Er(OAc)3 2-3 M Er5Si:ZnO-Sol Dipcoating sintering Films 1.53 < nD < 1.7 m L. Spanhel UV-vis Filmsintern bei 750°C 6 nm 25 nm 40 nm 83 nm 5 at.% Si/10 at.% Er/ ZnO 2% Er 1 % Er L 0% Er im».....*w« J_L ZnO JCPDS [140653] _I_l_ Er203 JCPDS [431007] I . . . I -1-1~ 20 25 30 35 40 45 50 55 60 2theta [°] L. Spanhel n cd n Lenses Glass 2dB/cm | \ 750°C;t~8 ms 'A &00°C;t < 50 |is ~i-1-1-1-1-r 1460 1500 1540 1580 1620 X[nm] durchstjmmbaret lose! 1456-1584 nm xyz Tech xyz Piezo EcZnO Tlsch Wetentertw ED opted spectrum anatyzef AO-6315A Optischer Netto Gewinn 1.5 urn : 3 dB/cm IHI /.. Spanhel 100 |im m L. Spanhel Optické zesílení ve vlnovodivých mikrostrukturách Er3+,Si4+@ZnO I KL)= ^r[egL-1] g = koeficient zesílení L = délka excitace g = 80 -100 cmV500 |im Výkon Laseru < 70 mW Interní zesílení l/l0 ~ 50 Chapter 4 Fractal approach to physical chemistry and materials science Chap. 4.1 Dimension ďun objet - D i 4-^ i <-► i CT J rej A0 = V0 = = (ti/4)í3 = (7i/6)£3 V I2 I3 On se propose d'occuper l'espace de dimension 1, 2 ou 3 de la longueur laterale - L avec un nombre N des initiateurs (molecules) ayant longueur (de liaison chimique) € N(L) = m L1 ' N(L) = nl_2 ► N(L) = pL3 , N(L) ~ C LD log N(L) = log C + D log L Relation generale pour les objets de n'importe quelle dimension 0< D<3! m L. Spanhel Concept of dimension - D in regular systems logN 0 = 1™-^- L^oo logL D = dimension of an object N = generator (collection of initiators) L = linear size of the object Regular objects are characterised by an integer dimension (D = 1, 2 or 3); Their density does not change D(hne) = iim—— = 1 L^co log2 La dimension fractale (Introduit par BenoTt Mandelbrot) n _ lo§ N U — lim-~ L^oo log L D = dimension of an object N = generator (collection of initiators) L = linear size of the object initiator generator N = 3 Fractal objects are characterised by a non-integer dimension (1 < D < 3); Their density drops with increasing size D (triangle) = iim = 1,584 L=2 N = 5 L=3 D (carre) = iim = 1,465 Fractal objects are self-similar Con^tru^tion^Ip^t^ ("iteration based construction") Analogie mathematique log N lim --; L^oo log L k log 3k -► F(x) -► log 2V N = 3 k, L = 2 k = 3 L. Spanhel Fractal Tetrahedron Initiator 1. Generation 2. Generation m L. Spanhel Fractal Octahedron k = 0 k = 1 log 6 log 2 = 2,585 N = 6k, L = 2k Fractal Dodecahedron /.. Spanhel II y a deux structures differentes et pourtant ayant la meme dimension fractale Structures fractales selon Vicsek: Df = log 5 / log 3 ~ 1.465 Croissance deterministe □af_ Gravure a I 'acide (ou corrosion) stochastique tJMI) L. Spanhel Cantor set w L. Spanhel Classification of fractals and summary of fractal rules 1. Formation par voie iteration soit I'extension soit subdivision 2. Autosimilarite I'observation du meme image sous n'importe quelle resolution 3. Types des fractales (en longueur, en surface et en volume) aerosols et poussieres fractales : 0 < D < 1 perimetres d'un grain ou d'une Tie, surfaces planes (mosaiques) 1 < D < 2 surfaces rocheuses, rugueuses D > 2 agregats colloi'daux, eponges : 2 < D < 3 4. Masse volumique n'est pas constant dans I'espace fractale! consequence: distributions multimodales de pores/particules souvent observees 5. Dimension fractale reflet le mecanisme de croissance structures deterministes (regulieres) et stochastiques (irregulieres) on trouve structures differentes ayant la meme dimension fractale! Chap. 4.2 Mesures expérimentales de Df D= Mm logNk €-0 log(1/€)k N(€) ~ € -D s = €/L "yardstick" Nombre des pixels carrés billes molecules N(8) ~ 8 d . Strategie principále: On cherche a compter le nombre de details en fonction de la taille du segment 8 choisi pour le recouvrement d'une structure complexe i L. Spanhel "Standard tiling relations" Longueur L (périmětre) = N(e) 8~8'D8~81'D Surface A (couche) = N(e) 82~8'D82~82 Volume V (agregát) = N(e) 83~8'D83~83 grandeur - (resolution d'une mesure) ß Power law! Dimension fractale de la cote littorale de Grande Bretagne Df = 1.31 Log N Cluster dendritique de zinc forme en electrolyse, Df ~ 1.7 Pente = Df Loa p. Physisorption des molecules Surface A = N(e) 82 - s 2 Physisorption de N2 (BET) Rappel: condensation capillaire Mesoporosite, 2 nm< R < 50 nm RD = - 2 y Vm / RT In (p/p°) Rp ~ 1 / In (p/p°) V = N(s) 6 3 ~ S3 ■D- Autre option: variation de la taille des molecules (s) appliquees en physisorption fJMJ) L. Spanhel Mesures SAXS, SANS, LALLS Continuum Network Surface Cluster Particle Atoms log scattering vector Fig. B2. Small-angle scattering curve for a disordered particle network. All structural features appear in the corresponding regions of scattering vector q. R and r denote a mean cluster ana particle size, respectively; exponents D and Ds, determining a power-law decay, are a measure of the morphology of network aggregates and particle surfaces, respectively. t = temps (ns, ^s) t = temps (ns, ns) p = D/s = 0,5 pour le réseau non-fractal avec s = 6 S = 6 implique ľinteractions dipóle - dipóle L. Spanhel L. Spanhel (p) /.. Spanhel (p) /.. Spanhel