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Spin-coated Films (spin-coated + film)
Selected AbstractsAnnealing-Free High Efficiency and Large Area Polymer Solar Cells Fabricated by a Roller Painting ProcessADVANCED FUNCTIONAL MATERIALS, Issue 14 2010Jae Woong Jung Abstract Polymer solar cells are fabricated by a novel solution coating process, roller painting. The roller-painted film , composed of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) , has a smoother surface than a spin-coated film. Since the roller painting is accompanied by shear and normal stresses and is also a slow drying process, the process effectively induces crystallization of P3HT and PCBM. Both crystalline P3HT and PCBM in the roller-painted active layer contribute to enhanced and balanced charge-carrier mobility. Consequently, the roller-painting process results in a higher power conversion efficiency (PCE) of 4.6%, as compared to that for spin coating (3.9%). Furthermore, annealing-free polymer solar cells (PSCs) with high PCE are fabricated by the roller painting process with the addition of a small amount of octanedi-1,8-thiol. Since the addition of octanedi-1,8-thiol induces phase separation between P3HT and PCBM and the roller-painting process induces crystallization of P3HT and PCBM, a PCE of roller-painted PSCs of up to 3.8% is achieved without post-annealing. A PCE of over 2.7% can also be achieved with 5,cm2 of active area without post-annealing. [source] V-Shaped Thiophene-Based Oligomers with Improved Electroluminescence Properties,ADVANCED FUNCTIONAL MATERIALS, Issue 4 2005G. Barbarella Abstract The synthesis via the Stille coupling of a new family of oligomers derived from benzo[b]thiophene is reported. Owing to their branched molecular structure lacking any symmetry element, these compounds display a low tendency to crystallization and better film-forming properties than their linear counterparts. Spin-coated films show photoluminescence efficiencies up to 50,%. Light-emitting diodes with spin-coated films as the active layers display markedly improved performance with respect to similar devices based on linear oligothiophenes, with luminance values up to more than 10,000,cd,m,2. Semiempirical PM3 and ZINDO/S calculations provide insight into the molecular geometries and electron distribution of the frontier orbitals of the new compounds. Cyclic voltammetry data indicates that the transformation of the thienyl sulfur of benzo[b]thiophene to the corresponding thienyl- S,S -dioxide leads an increase in electron affinity by 0.5,0.7,V, analogous to that of the corresponding linear oligomers. [source] Nanopatterning via Pressure-Induced Instabilities in Thin Polymer FilmsADVANCED MATERIALS, Issue 20 2009Ximin He The residual stresses in spin-coated films can be exploited to produce highly controlled nanoscale patterns via pressure-induced local rupturing and dewetting of thin films. Residue-free holes as small as 28,nm in diameter formed over large areas by pressing sharp stamps into polymer films at temperatures well below the glass transition temperature. [source] High Electron Mobility and Ambient Stability in Solution-Processed Perylene-Based Organic Field-Effect TransistorsADVANCED MATERIALS, Issue 16 2009Claudia Piliego Bottom-contact n-channel OFETs based on spin-coated films of N,N, -1H,1H -perfluorobutyl dicyanoperylenediimide (PDI-FCN2) exhibit a saturation-regime mobility of 0.15,cm2 V,1 s,1 in vacuum and good air stability. These performances are attributed to the high crystallinity and to the edge-on orientation promoted by the thermal treatment, as showed by confocal laser microscopy. [source] Structure Characterization of HSQ Films for Low Dielectrics Uses D4 as Sacrificial Porous MaterialsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2007Guiqin Yin Hydrogensilsesquioxane (HSQ) (low- k) films were prepared by spin-on deposition using D4 (octamethyl cyclotetrasiloxane) as a sacrificial porous material. The dielectric constant of silica films significantly changed from 3.0 to 2.2. Fourier transform infrared spectroscopy was used to identify the network structure and cage structure of the Si,O,Si bond and other bonds that may appear. We studied the structural and electrical properties of the spin-coated films prepared by mixing HSQ and D4 films after oxygen plasma exposure for 5 min, and studied the structural recovery of the damage by annealing at 350°C for 1.5 h in a nitrogen (N2) ambient. This structure results in significant lowering of the dielectric constant (k) on annealing at 350°C for 1.5 h in an N2 ambient and improvement in the leakage current density. [source] Dependence on substrate temperature of the conformation and structure of a poly[3-(4-octyloxyphenyl)thiophene] (POOPT) thin film obtained by matrix assisted pulsed laser evaporation (MAPLE)PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2009Valeria Califano Abstract In this paper, the substrate temperature influence on the structural and main opto-electronic properties of poly[3-(4-octyloxyphenyl)thiophene] (POOPT) films, deposited by matrix assisted pulsed laser evaporation (MAPLE), was analyzed. Fourier transform infrared analysis of films was performed to verify that laser irradiation has not induced polymer modifications or decomposition, confirming the reliability and high control of the MAPLE deposition technique. UV,Visible spectroscopy allowed gaining insights about films conformation and packing, while conductivity values have been measured by basic current,voltage measurements. In agreement with the experimental observations reported for other growth techniques, our results highlight the substrate temperature effect in promoting the film structural organization and improving their charge transport capability. At substrate temperature of 453,K, films deposited by MAPLE show a higher conjugation length in comparison with spin-coated films. The substrate temperature increase also favors side-chains commutation to different steric configurations. [source] Synthesis of star-shaped molecules with pyrene-containing ,-conjugated units linked by an organosilicon coreAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2010Joji Ohshita Abstract Star-shaped molecules with pyrene-containing ,-conjugated units linked by an organosilicon core (Py3Si and Py3C) were prepared and their applications to thin-film transistors (TFTs) and photovoltaic cells were studied. Bottom-contact type TFTs with spin-coated films of the star-shaped compounds as the active layers were prepared and the field-effect mobility (µFET) and Ion/Ioff ratios were determined to be approximately 10,5 cm2 V,1 s,1 and 104, respectively. Photovoltaic properties of Py3Si and Py3C were studied in the cells, ITO,PEDOT-PSS,Py3Si or Py3C-PCBM,LiF,Al. Although the power conversion efficiency (PCE) of the cells was only about 0.04%, they showed high open circuit voltages (Voc) of 0.8,0.9 V, indicating the high potential of this type of compound as a host material. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||