Experimental The oligomer synthesis and the physical characterizations have been pub- lishedelsewhere[15].Thethinsolidfilmsofpureoligomerswerepreparedby spin-coatingfromthechloroformsolutionat0.8and0.1%w/wrespectivelyor byevaporationunder10 ±6 mbarvacuum.ThefilmsinPVKforDFBmeasure- mentswereobtainedbydissolutionoftheoligomersatconcentrationsranging between5and50%.Thefilmswerespin-coatedontoglasssubstrates.Absorp- tionandphotoluminsecencewererecordedrespectivelywithaHitachiU-3000 spectrometer and PTI LPS-220B spectrofluorimeter. Light intensities were measuredwitha1cm 2 areaHamamatsusiliconphotodiode. U PL wasmeasured insolidfilmsusinganintegratingsphere(TRC-060-SLfromLabsphere)anda laser excitation at 411nm (PPm04 from Power Technology). The integrating sphereisahollowsphere,coatedinsidewithadiffuselyreflectingmaterial.The fluxreceivedatanapertureinthesphere(theexitport)isproportionaltothe totalamountoflightwithinthesphere,irrespectiveofitsangulardistribution. Thesamplesweremeasuredunderpurenitrogenatmosphereand U PL wascal- culatedbytakingintoaccounttheincidentlightabsorbeddirectlybythepoly- merfilmandafterinternalreflection[26]. The experimental DFB setup was presented elsewhere [23]. The pump source was a frequency tripled Q-switched mode locked Nd:YAG delivering 33pspulsesata10Hzrepetition.Thespotsizeofthebeamonthefilmwas 210 ±3 cm.Theemittedbeamwascollectedfromtheglassslidewaveguideinto anopticalfibercoupledwithaspectrometer. Received:April24,2002 Finalversion:July2,2002 ± [1] a) C.W. Tang, S.A. VanSlyke, Appl. Phys. Lett. 1987, 51,913.b)J.H. Burroughes, D.D.C. Bradley, A.R. Brown, R.N. Marks, K. Mackay, R.H.Friend,P.L.Burn,A.Kraft,A.B.Holmes, Nature 1990, 347,539. [2] C.J.Brabec,N.S.Sariciftci,J.C.Hummelen, Adv. Funct. Mater. 2001, 11, 15. [3] J.H.Schön,C.Kloc,A.Dodabalapur,B.Batlogg, Science 2000, 289,599. [4] O.P.Varnavski,J.C.Ostrowski,L.Sukhomlinova,R.J.Twieg,G.C.Ba- zan,T.GoodsonIII, J. Am. Chem. Soc. 2002, 124,1736. 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LeMoigne, B.Geffroy,J.M.Nunzi, Langmuir 2000, 16, 4309. [16] T. Maillou, Ph.D. Thesis, UniversitØ Louis Pasteur, Strasbourg, France 2001. [17] C.E. Halkyard, M.E. Rampey, L. Kloppenburg, S. Studer-Martinez, U.H.F.Bunz, Macromolecules 1998, 31,8655. [18] S.Hotta,K.Waragai, Adv. Mater. 1993, 5,896. [19] N.G.Pschirer,T.Miteva,U.Evans,R.S.Roberts,A.R.Marshall,D.Ne- her,M.L.Myrick,U.H.F.Bunz, Chem. Mater. 2001, 13,2691. [20] BotholigomerscrystallizeattheMeOH/CHCl 3 interfaceasyellowrhom- boidal platelets of few square millimetres, which are suitable for X-ray crystallographic characterization. The cell parameters of oNPE3 and oNPE5areasfollows:foroNPE3 a =15.518, b =8.476, c =35.225, and a = c =90, b =91.981; for oNPE5-b a =16.758, b =8.882, c =28.502,and a = c =90,and b =78.046. [21] J.P.Glusker,M.Lewis,M.Rossi, Crystal Structure Analysis for Chemists and Biologists,VCH,Weinheim 1994,p.647. [22] For oPE5Bz/PVK U PL =0.80,0.62,0.54,respectively,at33,10,and5% w/w.oNPE3,oNPE5-a,andbshowthesamerangeofvariations. [23] V. Dumarcher, L. Rocha, C. Denis, C. Fiorini, J. M. Nunzi, F. Sobel, B.Sahraoui,D.Gindre, J. Opt. A: Pure Appl. Opt. 2000, 2,279. [24] K.P.Kretsch,W.J.Blau,V.Dumarcher,L.Rocha,C.Fiorini,J.M.Nunzi, S.Pfeiffer,H.Tillmann,H.H.Hörhold, Appl. Phys. Lett. 2000, 76,2149. [25] Y.C.Kim,T.W.Lee,O.O.Park,C.Y.Kim,H.N.Cho, Adv. Mater. 2001, 13,646. [26] N.C.Greenham,I.D.W.Samuel,G.R.Hayes,R.T.Phillips,Y.R.R. Kessener,S.C.Moratti,A.B.Holmes,R.H.Friend, Chem. Phys. Lett. 1995, 241,89. Monodisperse Mesoporous Silica Microspheres Formed by Evaporation-Induced Self Assembly of Surfactant Templates in Aerosols** By G. V. Rama Rao, Gabriel P. López, Jaime Bravo, Hien Pham, Abhaya K. Datye, Huifang Xu,and Timothy L. Ward* Evaporation-induced self assembly (EISA) of amphiphilic molecules (e.g., surfactants and block copolymers) within aerosolsandthinfilmshasbeenrecentlydemonstratedtobe a powerful and flexible method for synthesizing ordered mesoporoussilicaparticles [1,2] andthinfilms. [2,3] Theprevious synthesis of mesoporous silica particles using aerosol EISA hasbeenlimitedtoparticlesizesofroughly1 lmorsmaller possessing a relatively wide particle size distribution. There aremanyapplicationswherelargermesoporousparticleswith highmonodispersityareneededorhighlybeneficial.Several examples include: controlled delivery, where monodispersity couldensureuniformdeliveryrates;biosensingbasedonflow cytometry, [4] wheremonodispersesphereswithsizesofseveral lmcouldserveasªcellmimicsº,andphotonicbandgapmate- rials, [5] wherehighmonodispersity,periodicity,andcontrolof thedielectricconstantarecriticalfactors.Herewereportfor the first time on the synthesis of non-hollow monodisperse mesoporoussilicaparticlesinthe5to10 lmsizerangebased onevaporation-drivensurfactanttemplatinginmicrodroplets produced by a vibrating orifice aerosol generator (VOAG). We show that pore size, mesoscopic ordering, and monodis- perseparticlesizecanbecontrolledbytheexperimentalcon- ditions,precursorchemistry,andVOAGparameters. Surfactant-templated mesoporous materials, initially dis- coveredbyMobilscientistsin1992, [6,7] havebeendeveloped to exhibit unique structures and properties, including uni- modal pore size distributions, high surface areas, alterable pore sizes and controlled pore surface chemistry. The meso- poresizerangeof2to50nmisattractiveforproducingcon- finedstructuressuchasquantumdots [8±10] ornanowires. [11,12] The highly uniform porosity of the mesoporous materials Adv. Mater. 2002, 14,No.18,September16 Ó 2002WILEY-VCHVerlagGmbH&Co.KGaA,Weinheim 0935-9648/02/1809-1301$17.50+.50/0 1301 COMMUNICATIONS ± [*] Prof.T.L.Ward,Dr.G.V.RamaRao,Prof.G.P.López,J.Bravo, Dr.H.Pham,Prof.A.K.Datye DepartmentofChemicalandNuclearEngineeringand CeramicandCompositeMaterialsCenter,UniversityofNewMexico Albuquerque,NM87131(USA) E-mail:tlward@unm.edu Dr.H.Xu DepartmentofEarthandPlanetarySciences,UniversityofNewMexico Albuquerque,NM87131(USA) [**] TheauthorsaregratefulforfinancialsupportfromtheAirForceOffice ofScientificResearch(GrantNo.318652)andtheNationalScienceFoun- dation(GrantNo.9812899).Dr.HongyouFan(SandiaNationalLabora- tories)isacknowledgedforhistechnicalassistance.