This PDF file contains the front matter associated with SPIE Proceedings Volume 7213, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Electron injection behavior from the magnesium (Mg) electrode into a family of electron-transporting amorphous molecular materials, 5,5'-bis(dimesitylboryl)-2,2'-bithiophene (BMB-2T) and 5,5''-bis(dimesitylboryl)-2,2':5',2''-terthiophene (BMB-3T), in single-layer devices of symmetrical structure was studied. The current density-voltage characteristics of the devices with varying thickness were in agreement with the trap-free space-charge-limited current model. The results indicate that the current is conduction limited and that the contact between BMB-nT (n = 2 and 3) and the Mg electrode is nearly ohmic.

Novel p-dopants of ReO₃ and CuI, and an n-dopant of Rb₂CO₃ have been developed. Among many other p-dopants, ReO₃ possesses superior characteristics of low temperature deposition, efficient charge generation and increasing the device lifetime. The absorption intensity of charge transfer complexes and current-voltage characteristics revealed that charge generation in p-doped hole transporting layers is more effective when the work function of the dopant is larger. High performance OLEDs have been fabricated using the p- and n-dopants, including the low driving voltage p-i-n phosphorescent OLEDs, high power efficiency of tandem OLEDs using ReO₃ doped NPB/ReO₃ (1 nm)/Rb₂CO₃ doped Bphen as the interconnection unit, and top emission OLEDs using CuI doped NPB as the hole injection layer from Ag electrode.

Regioregular monosubstituted polythienylvinylene (PTV) is a potentially important class of low band-gap conjugated polymers for photovoltaic research. We have recently reported the synthesis of a fully head-to-tail regioregular dodecyl-substituted PTV (HT-HT PDDTV). To balance high crystallization tendency and solution processibility, a series of PDDTV with controlled regioregularity have been synthesized using two isomeric co-monomers with molar ratios from 0:1, 1:9, 2:8, 3:7, 4:6 to 5:5, and solubility increases from less than 2 mg/mL to greater than 20 mg/mL in chloroform. The polymers are studied by ¹H and ¹³C NMR, UV-Vis absorption spectroscopy, differential scanning calorimetry and gel permeation chromatography. Preliminary study of photovoltaic performance has been conducted for 5:5 PDDTV.

Khoo et al.^{1, 2} have shown that nanosphere dispersed nematic liquid crystal (NDLC) constitutes a new type of metamaterial with index of refraction tunable from negative to positive values. Recently³ we have combined this approach with Monte Carlo simulations of inhomogeneous molecular order in planar NLC cells. Lebwohl - Lasher effective hamiltonian with Rapini - Papoular term for anchoring forces was used. Electric field and amplitude of anchoring forces are control parameters which determine the profiles of order parameter. In this paper we study, using the same approach, local spatial distribution of refractive index in NDLC planar cell. We show that NDLC material consists of layers with negative-zero-positive index of refraction. The spatial organization of those layers strongly depends on incident light wavelength. The role of spatially modulated external electric field for tuning of refractive index of NDLC is briefly discussed.

Nano-hybridization techniques based on the pyrolytic reactions of organo-soluble metallic precursors dissolved in poly(amic acid)s followed by spontaneous precipitation of metal/inorganic nano-particles in solid polyimide (PI) films is facile and effective for functionalization of PI optical and electronic materials. The organic/inorganinc PI nanohybrid materials, which were recently developed by the authors, having a variety of functionalities such as a) high refractive indices, b) low refractive indices, c) controlled thermo-optical property and its anisotropy, d) high polarizing property, and e) high thermal conductivity are reviewed with future prospects on their advanced opto-electronic applications.

We report a new method to study the photo-induced birefringence in polymers based on spectral fringes observed with white-light polarized light transmission. Here, a photo-induced birefringence in polymeric film was used to add a phase shift on the fringes pattern of one given reference thick waveplate. Basically, the period of the fringes and phase shift carry information about the thickness and birefringence of the reference waveplate and the film, respectively. The optical fringes were detected by a linear array spectrometer. We measured a birefringence induced by polarized argon-ion laser at 514 nm on azopolymer MDI-DR19 film.

In this paper, we present our recent progress to fabricate "plasmonic silver nanosheet" for highly sensitive biosensing devices. Uniformly sized silver nanoparticles (d = 4.8 nm ± 0.1 nm) are deposited on the substrate as a homogeneous nanosheet composed of two dimensional crystalline domains, in which the distance between silver cores is accurately controlled by the thickness of the capping organic molecules (myristate, alkanethiols). The silver nanosheet exhibits a significant shift of plasmon absorption band to the longer wavelength (ca. 50 nm) from the position in dispersion solution, while the peak width was rather reduced (sharpened) as an evidence of homogeneous coupling of local plasmons. We also found the unique coupling between propagating surface plasmon on gold thin film and localized surface plasmon on silver nanosheet. This flexible, transferable nanosheet, which can trap and transport bulk light at nano-interface, promises new application in the field of bio- and organic devices.

We present results of possible applications of a modified DNA-dye system for lasing and dynamic optical information recording. The system consisted of bio-polymeric matrix made of deoxyribonucleic acid (DNA) substituted with cationic surfactant molecule cetyltrimethyl-ammonium chloride (CTMA) and doped with a photochromic (Disperse Red 1) or fluorescent (Rhodamine 6G) molecules. Results of optical information recording were obtained in a typical degenerate two wave mixing experiment. For sample excitation we used a linearly polarized light of λ = 514.5 nm delivered by an argon ion (Ar⁺) laser. For amplified spontaneous emission measurements we used 6 ns pulses of 532 nm wavelength delivered by Nd:YAG laser doubled in frequency.

Graded-index (GRIN) progressive addition lens (PAL) was successfully fabricated, and GRIN's potential for aberration correction of PAL was confirmed. GRIN material was prepared by partial diffusion of methyl methacrylate (MMA (n_d at polymer = 1.492)) monomer into cross-linked benzyl methacrylate (BzMA (n_d at polymer=1.568)) flat gel, and GRINPAL was prepared by polymerization of the GRIN material attached to a mold of commercially available PAL. GRIN polymer materials have been used for various applications such as rod lenses and optical fibers. GRIN represents gradual change of refractive index in a material, which adds or reduces light focusing power of the material. PAL is a multifocal spectacle lens for presbyopia. However, some localized aberrations (especially astigmatism) in PAL have not yet been reduced satisfactorily for decades by optimizing surface geometry of a lens. In this research, we propose to employ GRIN materials for astigmatism reduction of PALs. BzMA flat gel was prepared by UV polymerization of BzMA, crosslinking agent ethylene glycol dimethacrylate (EDMA) and photopolymerization initiator DAROCURE 1173. MMA monomer was diffused into BzMA flat gel from a portion of periphery for several hours. The obtained GRIN material was attached to a mold of commercially available PAL and polymerized by UV. As a result, reduction of astigmatism was confirmed locally in the fabricated PAL and GRIN-PAL using lens meter. In conclusion, GRIN-PAL was successfully fabricated. The validity of GRIN employment for the astigmatism reduction in PAL was demonstrated experimentally.

We report simultaneous two-photon absorption (2PA) spectra in a series of substituted corroles and related porphyrins in 800-1400 nm laser wavelength range. Compared to the porphyrins, the 2PA spectrum of corroles contains a distinct and relatively high intensity peak, sigma(2) = 60-130 GM, close to twice the wavelength of Soret maximum (800-850 nm). The increase of 2PA peak cross section is explained in terms of decreased symmetry of the contracted macro-cycle, and is most likely related to relaxing of the parity selection rules that restrict 2PA in the Soret band for more symmetrical porphyrins. We also observe that the strength of the 2PA peak in Soret region decreases with the electron-withdrawing ability (increasing Hammett constant) of the side substituents, which can be explained by assuming that the corrole core itself possesses electron-accepting ability. The peak 2PA cross sections in the Q-region are much less than in Soret-region, and can be quantitatively described within the two-level approximation taking into account permanent dipole moments in the ground and excited states.

Detailed studies of the dynamics of a continuous wave, visible laser beam propagating in a photopolymerizable organosiloxane are presented. Experiments carried out at intensities ranging across ten orders of magnitude (3.2 x 10^-5 Wcm^-2 to 12732 Wcm^-2) revealed three types of nonlinear behaviour. In the low-intensity regime, the beam self-trapped and exhibited complex oscillatory behaviour, which signified the excitation of high-order modes in its self-inscribed waveguide during self-trapping. This is consistent with previous theoretical predictions of self-trapping in 1-photon systems including photopolymers. In the mid-intensity regime, the beam underwent spatial self-phase modulation, which elicited spatial diffraction rings. While this phenomenon has been observed in Kerr, liquid crystals and absorptive materials, it has until now been neither theoretically nor experimentally observed in photopolymers. Rapid and large refractive index changes induced in the high-intensity regime caused filamentation of the beam. These studies provide a comprehensive overview of nonlinear light propagation in photopolymers.

Intensive research on optical interconnections has attracted considerable attention for high-end router and server applications. A polymer film waveguide is expected to be applied to an optical circuit board in an optical interconnection. The film waveguide requires a conventional connector if it is to be employed as a practical optical circuit board. This paper describes the MT connector used with polymer film waveguide (PMT connector), which is compatible with the MT connector used with optical fiber. This connector can be attached to a film waveguide by passive alignment, and is used to connect waveguides. When the connector was equipped with an epoxy resin film waveguide, the insertion and connection losses were less than 1.4 and 0.5 dB, respectively. These losses are sufficiently small to meet the basic requirement for optical circuit boards, so we were able to fabricate a flexible optical circuit board with PMT connectors. This paper also describes the application of a film waveguide with PMT connectors to an optical front plane system.

The purpose of this study is to design an optimal strontium carbonate (SrCO₃) crystal which can effectively compensate the orientational birefringence of polymers. Additionally, we try to compensate large positive birefringence which polycarbonate (PC) exhibits. Furthermore, we analyze the orientational behaviors of the crystals in biaxially drawn polymer films. As a result of the measurement of orientational birefringence of the polymer films doped with SrCO₃ with various average sizes and aspect ratios and estimation of orientation function of the crystals, we found out that SrCO₃ with higher aspect ratio and larger size had higher compensation efficiency for the birefringence. As a result of measurement of transparency, we found out that the copolymer film doped with SrCO₃ with higher aspect ratio and larger size was less transparent. Therefore, it was suggested that we should design an optimal crystal for particular purposes from the standpoint of the birefringence compensation efficiency and transparency when we apply this method to an optics application. Additionally, we succeed in designing a zero birefringent PC by doping with SrCO₃. Furthermore, we found out that SrCO₃ was aligned in a perpendicular direction to the thickness direction and was randomly oriented in planar direction in biaxially drawn polymer films.

The graded index polymer optical fiber (GI POF) has been proposed as a media for very short reach network because of its high flexibility, low laying cost and excellent transmission characteristics. However, the plasticization efficiency which causes by the high refractive dopant decreases the glass transition temperature (T_g) in the center of the core and deteriorates thermal stability of fibers. In this paper, thermally stable PMMA based GI POF was successfully fabricated for the first time by designing dopant molecule which has little plasticizer effect. T_g at the core region was improved to 104 °C while that of conventional GI POF is 86 °C. Stability of attenuation at 85 °C/dry and 75 °C/85 %RH were clarified to be as high as that of non-doped step index POF.

Optical components based on waveguides and gratings are in use in several areas of optical communication and sensor technology. Such structures are realized in both inorganic and organic materials with different more or less complex fabrication methods. The inscription of optical structures induced by deep ultra violet (DUV) radiation in homogeneous polymer substrates is a relatively simple lithographic one step process in comparison to other established fabrication methods. For this technology the irradiation process was enhanced whereby the writing time was shortened. The writing time to achieve a refractive index change in the order of magnitude of 10^-3 is now in the range of a few minutes. Various polymers were investigated and their suitability for waveguide applications was compared. Some of the polymethylmethacrylate (PMMA) based copolymers have a relatively high glass transition temperature (T_g) of over 140°C. These optical polymers have the potential to be applied at higher temperatures than commercial PMMA based polymers. The modification zone was characterised by several methods. The main points of the work were the determination of the refractive index and the optical loss of the waveguides. Grating structures were generated by the phase mask method. The optical functionality of these gratings is described.

Nanoparticles doped PMMA films were prepared without surface treatment agent in order to investigate particle size and concentration dependence of orientation-inhibition effect and photoelastic coefficient reduction. It is suggested that nanoparticles with a diameter of less than about 30 nm exhibit orientation-inhibition effect. Photoelastic coefficient reduction was independent of particle size and proportional to volume fraction. Doping nanoparticles has an insignificant effect on degrading the transparency of polymers if the combination of nanoparticles and polymer matrix is appropriate.

Pyroelectric infrared radiation detectors are one of kind thermal sensors, operating at ambient temperature, unlike semiconductor detectors, which require cooling. They also have a uniform spectral response in a wide range of wavelengths, including the main band of infrared transmission of the earth's atmosphere. Recently, 0-3 composites consisting of ferroelectric ceramic particles dispersed in a ferroelectric polymer have stimulated interest due to their good mechanical flexibility and strength, and excellent piezoelectric and pyroelectric properties. Lithium tantalite [(LiTaO₃), LT] ceramic particles have been incorporated into a polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE) 70/30 mol%] copolymer matrix to form composite films. The films were prepared using solvent casting method with the LT powder homogeneously dispersed in the P(VDF-TrFE) copolymer matrix with various volume fractions. Electrical properties such as the dielectric constant, dielectric loss, and pyroelectric coefficient have been measured as a function of temperature as well as frequency. In addition, materials' figures-of-merit have also been calculated to assess their use in infrared detectors. The results show that the fabricated lithium tantalite: polyvinylidene fluoride-trifluoroethylene composite films have a good potential for uncooled infrared sensor applications operating at moderate temperatures.

We have investigated the role of interfaces in the formation of traps in organic devices using poly(9,9-dihexylfluorene-co-N,N-di(9,9-dihexyl-2-fluorenyl)-N-phenylamine) (PF-N-Ph) as an emissive material. The basic structure of the studied diodes is ITO/PEDOT:PSS/PF/M where M is Al or Ca/Al. Trap parameters have been measured by Charge based Deep Level Transient Spectroscopy (Q-DLTS) in diodes having different electrode configurations. Five trap levels have been identified in the basic device structures with activation energies in the range of 0.1 - 0.6 eV and trap densities in the range of 10¹⁶ - 10¹⁷ cm^-3. On the cathode side, no noticeable changes have been observed when changing the electrode from aluminium to calcium. On the anode side, comparing the trap parameters in devices with and without a PEDOT:PSS layer, we show that the hole injection layer introduced new trap levels, which are electron-traps. The density of these traps is of the order of 10¹⁶ cm^-3 and their levels are at ~ 0.3 and ~ 0.5 eV from the band edges. The findings confirm and complete quantitatively earlier results by other groups on the role of the PEDOT:PSS /organic interface in the trap formation in OLEDs.

We have succeeded in development of a simulation specialized for GI POF. In this study, we investigated the propagation characteristics of GI POF by use of this simulation. Propagation properties of multi-mode optical fibers can be calculated by the scalar-wave equation derived from Maxwell's equations. However, calculated impulse response disagrees with measured results. The factors of this disagreement have been generally explained as mode coupling and differential mode attenuation. These effects can be calculated by the power flow equation, as it has been applied for analysis of glass optical fibers and step-index polymer optical fibers. In this study, we applied the power flow equation to the graded-index polymer optical fiber (GI POF). The equation contains several parameters: propagation constants, coupling coefficients, and attenuation coefficient. In order to define these parameters, we fabricated poly methyl methacrylate (PMMA) based GI POF. Propagation constants of the GI POF were calculated by use of the finite-element method. Coupling and attenuation coefficients were estimated based on comparisons of measurements with simulation of differential mode attenuation and differential mode delay. We assigned these values to the power flow equation and solved it by use of the finite difference method. As a result, bandwidth characteristics calculated by this simulation well agreed with measurements. Moreover, it was found that the effect of mode coupling on impulse response of GI POF was more influential than that of differential mode attenuation and that higher modes were subject to mode coupling than lower modes and they were coupled into lower mode.

Polymer optical waveguide devices are getting popular for optical printed circuit board and/or home-network applications. In order to accelerate the development of polymer optical waveguide devices, evaluation of waveguide characteristics should be reliable and speeded up. Polymer optical chip containing a combination of 45°-angled cut waveguide, Y-splitter and S-bend structures was designed and fabricated for simple evaluation of multimode waveguides. Input launching conditions such as mode scrambler was investigated for reliable measurement for standardization.

The phosphorescence polymer LEDs (PhPLEDs) with the structure of ITO/PEDOT:PSS/PVK:Ir(ppy)₃/TPBI/LiF/Al were fabricated and investigated on the electrical and optical properties at variations doping concentrations (0.5wt% to 2.5wt%) of Ir(ppy)₃. PVK(poly-vinylcarbazole) and Ir(ppy)₃[tris(2-phenylpyridine)iridium(III)] polymers were used as the host and guest materials for the emission layer. TPBI was introduced to improve the light efficiency of the devices. The maximum luminance and current density for PhPLED were about 8600 cd/m² and 155 mA/cm² at 7 V, when the TPBI layer was introduced between emission and cathode electrode film. The emission spectrum and the CIE color coordinator were about 512nm and x, y = 0.28, 0.63, respectively, showing green color.

Organic nonlinear optical (NLO) materials have attracted much interest for their potential applications over the past two decades mainly because of their faster electronic response and larger optical nonlinearities than the conventional inorganic materials. Especially, electro-optic (EO) polymers have been promising candidates for fast and broadband EO modulators as a result of the development of the 2nd-order NLO chromophore. In this manuscript, we report fabrication and design of one dimensional (1D) polymeric photonic crystals (PCs) to additionally enhance the optical nonlinearities of the organic NLO materials. We fabricated polymeric high-reflection mirrors for 1D PCs by a simple alternatively spin-coating two polymers under control of their optical thickness, in which a novel polymer was applied to the higher refractive index layer. We also designed defect-mode 1D polymeric PC for effective light-localization in the defect layer and discussed their effect for enhancement of the 2nd-order optical nonlinearities.

Organic light-emitting diodes (OLEDs) with NPB/LiF multiple layers were proposed and fabricated. It was found that the insertion of NPB/LiF multiple layers can balance the charge injection and transport, which is helpful in enhancing the performance of OLEDs. It was also found that we can achieve the device with the best performance from the OLED with three pairs of LiF/NPB (0.3nm/15nm).

We have successfully demonstrated enhancement of the two-photon excited fluorescence (TPEF) in a highly nonlinear optical polymer two-dimensional (2D) photonic crystal (PhC) waveguide, arising from resonant coupling between the external laser field and a photonic band mode. Moreover, we directly determine the experimental photonic band dispersion structure of waveguiding modes under the light line in a 2D PhC waveguide by using angle-resolved attenuated total reflection spectroscopy. Resonance coupling between the external evanescent wave from total reflection within the prism and the waveguiding modes in the 2D PhC provides clear information on individual band components by resolving the angle (i.e., wave vector k) and photon energy. The experimentally determined photonic band structure is essential for understanding the novel light propagation and nonlinear optical properties of PhC systems. Good agreement was obtained between the TPEF enhancements and features of the photonic band structure, indicating that active manipulation of these nonlinear TPE processes is a realistic possibility through engineering the band dispersion and band group velocity characteristics. Future work in this direction should lead to dramatic improvements in the performance of TPE applications.

White organic light-emitting diodes (OLEDs) have attracted great attention recently. In this study, high-efficiency white organic light-emitting diodes with dotted-line doped layers are numerically investigated with the APSYS (abbreviation of Advanced Physical Model of Simulation Devices) simulation program. The APSYS simulation program, developed by Crosslight Inc., is capable of dealing with the optical, electrical, and thermal characteristics of OLED devices. To approach the real situation, the OLED device fabricated by Park et al. (Current Applied Physics 1, 116, 2001) was first modeled by adjusting the appropriate physical parameters. Based on this OLED structure, a new structure of ITO/α-NPD (40 nm)/Alq₃:DCJTB (30 nm)/Alq₃ (30 nm)/Mg:Ag emitting quasi-white light was then proposed. Then, the single layer of Alq₃:DCJTB was replaced by multi-(Alq₃:DCJTB/Alq₃)n layers, which are the so-called dotted-line doped layers (see, e.g., paper by Han et al., Solid State Communications 141, 332, 2007), to further improve the optical performance. The optical properties of the white OLEDs with different pairs of (Alq₃:DCJTB/Alq₃)n dotted-line doped layers are investigated and discussed in detail. Optimization of the proposed quasi-white OLED structures is attempted. The simulation results indicate that the OLED with dotted-line doped layers has higher radiative recombination rate and better emission efficiency than that with a single Alq₃:DCJTB layer. The physical origin of the improved optical performance for the OLED with dotted-line doped layers could be due to the increased electrons and holes at the interfaces between the Alq₃:DCJTB and Alq₃ layers, which thus results in higher radiative recombination rate and better emission efficiency.

In order to produce high performance SWNT-based products, it is necessary to make them soluble, reaching a certain degree of dispersion and stability in solution. Since SWNTs are mostly inert, being neither hydrophilic nor lipophilic, their use suffers from poor dispersion capability and weak interaction with other partners. Therefore, activating and modifying their surface is an essential prerequisite to processing. We report on a versatile nondestructive strategy for the non-covalent functionalization of SWNT by polyelectrolytes based on maleic anhydride copolymers. To evaluate competing stabilization characteristics, we explored the dispersing power of a range of maleic anhydride copolymers functionalized with several chromophore units: pyrene, cholesterol and Disperse Red 1. The surface modification of SWNT is straightforward and efficient for making them dispersible in water and in other organic solvents and for producing nanometer-scale materials suitable for nanotechnology, medicinal chemistry and environment friendly solar cell applications.