Browsing by Author "Yang, Sheng-Hsiung"

Now showing 1 - 20 of 43

Annealed zinc oxide films for controlling the alignment of liquid crystals
(2017-08-01)
Hu, Jia-Wei
;
Yang, Sheng-Hsiung
;
Jeng, Shie-Chang
;
光電系統研究所
;
照明與能源光電研究所
It is observed that the anchoring of LC molecules aligned on the ZnO film depends on the surface wettability. We demonstrate that the surface wettability of ZnO films fabricated by sol-gel process can be modified by annealing. The observations using the scanning electron microscope, photoluminescence and X-ray photoelectron spectroscopy for ZnO films have shown that the annealing can modify both the morphologies and chemical compositions of ZnO films, which in turn produces influences on the surface wettability. The surface wettability of as-prepared ZnO film can be controlled from 102 degrees to 60 degrees (contact angle (CA) of water) as the annealing temperature increases from 190 to 250 degrees C. Our experimental results show that the pretilt angles of LCs on ZnO films can be modified over a wide range from 89.5 degrees to 0.5 degrees as the CA of water on the ZnO films changes from 102 degrees to 60 degrees.
Color tuning in thermo-sensitive chiral photonic liquid crystals based on the pseudo-dielectric heating effect
(2019-12-15)
Yeh, Min-Chih
;
Yang, Sheng-Hsiung
;
Lee, Wei
;
照明與能源光電研究所
;
影像與生醫光電研究所
The ability of electro-thermal tuning in center wavelength (X,) of the Bragg reflection band is promoted in cholesteric liquid crystal (CLC) containing a positive-dielectric-anisotropy liquid crystal host (E7) and a binary chiral dopant (R-811 and R-5011). In the CLC mixtures with a fixed R-811 content of 30 wt%, the transition temperature of the smectic-A phase to CLC phase decreases when the R-5011 loading increases. The CLC systems are temperature-sensitive, each exhibiting a temperature range of about 9-12 degrees C in the CLC phase. Optimization of the content of R-5011 at 1.5 wt% allows for the remarkably effective thermal tuning in lambda(c )from 780 nm to 380 nm in response to a temperature increase of merely 3 degrees C from the room temperature. Under the mechanism of pseudo-dielectric heating, the tunable lambda(c) can shift in the entire visible spectrum by an applied voltage as low as 7 V-rms at a frequency of 2 MHz across the cell gap of a 4.8-mu m-thick cell. Furthermore, a multifunctional and operation-reversible device is demonstrated by the control of the applied AC voltage, yielding an optical device in which the reflection band can be tuned and the mode can be switched among the reflection, scattering, and transparent states. (C) 2019 Elsevier B.V. All rights reserved.
Dielectrophoretic placement of quasi-zero-, one-, and two-dimensional nanomaterials into nanogap for electrical characterizations
(2012-08-01)
Lin, Yen-Fu
;
Chiu, Shao-Chien
;
Wang, Sheng-Tsung
;
Fu, Sheng-Kai
;
Chen, Chien-Hsiang
DEP is one of promising techniques for positioning nanomaterials into the desirable location for nanoelectronic applications. In contrast, the lithography technique is commonly used to make ultra-thin conducting wires and narrow gaps but, due to the limit of patterning resolution, it is not feasible to make electrical contacts on ultra-small nanomaterials for a bottom-up device fabrication. Thus, integrating the lithography and dielectrophoresis, a real bottom-up fabrication can be achieved. In this work, the device with the nanogap in between two nanofinger-electrodes is made using electron-beam lithography from top down and the ultra-small nanomaterials, such as colloidal PbSe quantum dots, polyaniline nanofibers, and reduced-graphene-oxide flakes, are placed in the nanogap by DEP from bottom up. The threshold electric field for the DEP placement of PbSe nanocrystals was roughly estimated to be about 8.3 x 104 V/cm under our experimental configuration. After the DEP process, several procedures for reducing contact resistances are attempted and measurements of intrinsic electron transport in versatile nanomaterials are performed. It is experimentally confirmed that electron transport in both PbSe nanocrystal arrays and polyaniline nanofibers agrees well with Prof. Ping Sheng's model of granular metallic conduction. In addition, electron transport in reduced-graphene-oxide flakes follows Mott's 2D variable-range-hopping model. This study illustrates an integration of the electron-beam lithography and the DEP techniques for a precise manipulation of nanomaterials into electronic circuits for characterization of intrinsic properties.
"Dielectrophoretic placement of quasi-zero-, one-, and two-dimensional nanomaterials into nanogap for electrical characterizations"
(2012-08-01)
Lin, Yen-Fu
;
Chiu, Shao-Chien
;
Wang, Sheng-Tsung
;
Fu, Sheng-Kai
;
Chen, Chien-Hsiang
"DEP is one of promising techniques for positioning nanomaterials into the desirable location for nanoelectronic applications. In contrast, the lithography technique is commonly used to make ultra-thin conducting wires and narrow gaps but, due to the limit of patterning resolution, it is not feasible to make electrical contacts on ultra-small nanomaterials for a bottom-up device fabrication. Thus, integrating the lithography and dielectrophoresis, a real bottom-up fabrication can be achieved. In this work, the device with the nanogap in between two nanofinger-electrodes is made using electron-beam lithography from top down and the ultra-small nanomaterials, such as colloidal PbSe quantum dots, polyaniline nanofibers, and reduced-graphene-oxide flakes, are placed in the nanogap by DEP from bottom up. The threshold electric field for the DEP placement of PbSe nanocrystals was roughly estimated to be about 8.3 x 104 V/cm under our experimental configuration. After the DEP process, several procedures for reducing contact resistances are attempted and measurements of intrinsic electron transport in versatile nanomaterials are performed. It is experimentally confirmed that electron transport in both PbSe nanocrystal arrays and polyaniline nanofibers agrees well with Prof. Ping Sheng's model of granular metallic conduction. In addition, electron transport in reduced-graphene-oxide flakes follows Mott's 2D variable-range-hopping model. This study illustrates an integration of the electron-beam lithography and the DEP techniques for a precise manipulation of nanomaterials into electronic circuits for characterization of intrinsic properties."
Efficiency enhancement of regular-type perovskite solar cells based on Al-doped ZnO nanorods as electron transporting layers
(2017-02-01)
Huang, Zheng-Lun
;
Chen, Chih-Ming
;
Lin, Zheng-Kun
;
Yang, Sheng-Hsiung
;
光電工程學系
In this paper, we first incorporated Al(NO3)(3 center dot)9H(2)0 as the Al source into ZnO nanorods (NRs) lattice via the hydrothermal method to modify nature properties of ZnO NRs for the fabrication of perovskite solar cells (PSCs). The X-ray diffraction (XRD) pattern of Al-doped ZnO NRs exhibits higher 20 values and stronger intensity of (002) plane. Larger optical band gap and higher electrical conductivity of Al-doped ZnO NRs are also observed relative to non-doped ZnO ones. The steady-state photoluminescence shows effective charge extraction and collection at the interface between Al-doped ZnO NRs and perovskite layer. The optimized PSC based on Al-doped ZnO NRs showed an open-circuit voltage of 0.84 V, a short-circuit current density of 21.93 mA/cm(2), a fill factor of 57%, and a power conversion efficiency of 10.45% that was 23% higher than the non-doped ZnO ones. (C) 2016 Elsevier Ltd. All rights reserved.
Electroluminescence from a conjugated polymer grafted with CdSe/ZnS: High brightness and improved efficiency
(2006-09-15)
Chen, Kuei-Bai
;
Chen, Ming-Hwey
;
Yang, Sheng-Hsiung
;
Hsieh, Chao-Hsiang
;
Hsu, Chain-Shu
A new series of sulfide-substituted poly(1,4-phenylene vinylene) derivatives (S1PPV-S3PPV) with different composition ratios were successfully synthesized,via the Gilch route. The CdSe/ZnS were grafted to the sulfur atoms by ligand exchange reaction. The grafted CdSe/ZnS contents were determined from TGA analysis to be from 4.6 to 37.8%. A new peak at 1151 cm(-1) formed in FT-IR after ligand exchange, which is attributed to the force formation between sulfur and CdSe. The GPC results show that the molecular weights of final polymers became higher after ligand exchange. Thin films of obtained polymers emitted bright green and yellow light with the max emission peak located from 546 to 556 nm. Double-layer LEDs with an ITO/PEDOT/polymer/Ca/Al configuration were fabricated to evaluate the potential use of these polymers. The turn-on voltages of the devices were about 4-5 V As the CdSe/ZnS content increased in grafted polymers, the device performance was significantly enhanced as compared to pristine polymers. In the case of S3PPV, the double-layer device showed a maximum luminance of 6073 cd/m(2) with a current yield of 0.82 cd/A. The maximum luminance and current yield was enhanced to 13,390 cd/m(2) and 2.25 cd/A by grafting CdSe/ZnS onto polymers. (c) 2006 Wiley Periodicals, Inc.
Fabrication of MEH-PPV/SIO2 and MEH-PPV/SIO2 nanocomposites with enhanced luminescent stabilities
(2007-10-01)
Yang, Sheng-Hsiung
;
Le Rendu, Philippe
;
Nguyen, Thien-Phap
;
Hsu, Chain-Shu
;
應用化學系
Thin films of composites made by incorporation of silicon oxide (SiO2) or titanium oxide (TiO2) nanoparticles into poly[2-methoxy-5-(2'-ethylhexoxy-p-phenylene vinylene] (MEH-PPV) were deposited by spin-coating from p-xylene solutions and their optical properties were investigated. SEM images showed that different extents of aggregates were formed for two kinds of nanocomposites. The UV-vis absorption spectra of MEH-PPV/SiO2 and MEH-PPV/TiO2 films showed a small red shift (similar to 5 nm) as compared with that of pristine polymer. However, the structure of MEH-PPV was not affected as revealed by infrared and Raman experiments. This result is different from that obtained in PPV/oxide nanocomposites in which, the conjugated length of PPV main chain was reduced. Similarly, a small red shift was found in PL emission spectra with increasing the content of oxide nanoparticles. The PL degradation experiments showed that blending with SiO2 nanoparticles could enhance the luminescent stability of MEH-PPV By blending with 8% SiO2 nanoparticles of 20 nm diameter, the PL intensity of MEH-PPV film attained 46% of the original one, while it decreased to 20% for pristine MEH-PPV after four weeks of exposure to ambient air. The effect of TO2 nanoparticles to stabilize MEH-PPV thin films is though less important than that of SiO2.
Growth of ZnO Nanorods and Their Applications for Liquid Crystal Devices
(2018-04-01)
Chen, Mu-Zhe
;
Yang, Sheng-Hsiung
;
Jeng, Shie-Chang
;
光電系統研究所
;
照明與能源光電研究所
Different morphologies of ZnO nanorods were synthesized by using the two-step hydrothermal method, and they were applied to liquid crystal (LC) alignment films. The morphology of the ZnO nanorods, including length, diameter, and density, were controlled by the growth time, which ranged from 16 to 26 min. The morphology and the chemical features both contributed to the surface wettability of the ZnO nanorods. The LC pretilt angle on the ZnO nanorods was successfully controlled from homeotropic (similar to 89.0 degrees) to homogeneous (similar to 1.7 degrees) alignments, as the contact angle of water on ZnO nanorods was changed from 93 to 28 with the growth time. The analysis of Xray diffraction and X-ray photoelectron spectroscopy showed that the crystallite size of ZnO nanorods increased with the growth time, while the oxygen vacancy decreased. The ZnO nanorods grown on the ITO glass substrate also improve the transmission of LCDs due to the antireflection effect.
Highly substituted poly(2,3-diphenyl-1,4-phenylenevinylene) derivatives having bulky phenyl and fluorenyl pendant groups: Synthesis, characterization, and electro-optical properties
(2006-12-01)
Yang, Sheng-Hsiung
;
Li, Hsing-Chuan
;
Chen, Chien-Kai
;
Hsu, Chain-Shu
;
應用化學系
Two series of poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV) derivatives containing multiple bulky substituents were synthesized. In the first series, two different groups were incorporated on C-5,6 positions of the phenylene moiety to increase steric hindrance and to obtain blue-shifted emissions. In the second series, bulky fluorenyl groups with two hexyl chains on the C-9 position were introduced on two phenyl pendants to increase the solubility as well as steric hindrance to prevent close packing of the main chain. Polymers with high molecular weights and fine-tuned electro-optical properties were obtained by controlling the feed ratio of different monomers during polymerization. The maximum photoluminescent emissions of the thin films are located between 384 and 541 nm. Cyclic voltammetric analysis reveals that the band gaps of these light-emitting materials are in the range from 2.4 to 3.3 eV A double-layer EL device with the configuration of ITO/PEDOT/P4/Ca/Al emitted pure green light with CIE ' 1931 at (0.24, 0.5). Using copolymer P6 as the emissive layer, the maximum luminescence and current efficiency were both improved when compared with the homopolymer P4. (c) 2006 Wiley Periodicals, Inc.
Hybrid light-emitting devices by incorporating WO3 nanorod arrays as the electron transport layer and PEIE as the buffer layer
(2018-01-01)
Chang, Chun-Kai
;
Wang, Szu-Ping
;
Yang, Sheng-Hsiung
;
Puaud, Apolline
;
Thien-Phap Nguyen
In this research, we demonstrate novel inverted light-emitting devices based on n-typed tungsten trioxide (WO3) nanostructures. Two different types of WO3 nanostructures, including nanocluster layer (NCL) and nanorod arrays (NAs), were grown on the indium-tin oxide (ITO) substrates by the hydrothermal method. An ultra-thin polyethylenimine ethoxylated (PEIE) layer was deposited on top of WO3 nanostructures as the buffer layer for improving device performance. Inverted devices with the configuration of ITO/WO3 NCL or NAs/PEIE/poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/WO3 film/Au were constructed and evaluated. The best device based on WO3 NAs with height of 300 nm showed a max brightness of 3079 cd/m(2) and current efficiency of 0.22 cd/A. Our observation and results open up new opportunities to fabricate hybrid light-emitting devices. (C) 2017 Elsevier Ltd. All rights reserved.
Improved Efficiencies in Organic Light Emitting Diodes Made with CdSe/ZnS Quantum Dots and a Semiconducting Polymer
(2009-03-01)
Lee, Chih-Wen
;
Yang, Sheng-Hsiung
;
Hsu, Chain-Shu
;
Meng, Hsin-Fei
;
應用化學系
In this study, we report the fabrication and characterization of organic/inorganic hybrid polymer light emitting diodes (PLEDs) made with ZnS-capped CdSe core/shell type nanocrystals and a light-emitting polymer poly[2-phenyl-3-(9,9-dihexylfluoren-2-yl)-1,4-phenylene vinylene]-co-[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene]. The device using pristine polymer as active layer emitted yellow light with a maximum brightness of 3949 cd/m(2) and maximum external quantum efficiency of 0.27 cd/A at 10 V. After blending with the CdSe/ZnS quantum dots (QDs), the device showed a much higher brightness of 8192 cd/m(2) and external quantum efficiency of 1.27 cd/A at 7 V, while the driving voltage was lowered. The experimental results revealed that CdSe/ZnS QDs act as a hole-blocker in the devices. More efficient electron-hole recombination process inside polymer layer results in large improvement in luminescence and efficiency.
Improved efficiency of perovskite solar cells based on Ni-doped ZnO nanorod arrays and Li salt-doped P3HT layer for charge collection
(2016-11-01)
Chen, Pin-Yao
;
Yang, Sheng-Hsiung
;
照明與能源光電研究所
;
Institute of Lighting and Energy Photonics
We demonstrate regular-type perovskite solar cells based on vertically grown Ni-doped ZnO nanorod arrays and doped P3HT for solar energy harvesting. PCBM was introduced between Ni-doped ZnO nanorod arrays and the perovskite layer to improve electron extraction, while P3HT doped with bis(trifluoromethane) sulfonimide lithium salt (Li-TFSI) was used as hole transporting layer. Three types of perovskite materials, including MAPbI(3), (MA)(x)(FA)(1-x)PbI3, and (MA)(y')(GA)(1-y)PbI3, were used as light harvesting layers to exploit conversion efficiency of photovoltaic devices. The optimized perovskite solar cell with the configuration of ITO/Ni-doped ZnO nanorods/PCBM/(MA)(y)(GA)(1-y)PbI3/P3HT + Li-TFSI/Au revealed an open-circuit voltage of 0.83 V, a short-circuit current density of 23.73 mA/cm(2), a fill factor of 70%, and a power conversion efficiency of 13.79%. (C) 2016 Optical Society of America
Incorporation of quaternary ammonium salts containing different counterions to improve the performance of inverted perovskite solar cells
(2017-02)
Yan, Po-Ruei
;
Huang, Wei-Jie
;
Yang, Sheng-Hsiung
;
光電工程學系
;
Department of Photonics
In this research, three quaternary ammonium salts containing different counterions, including tetrabutylammonium bromide (TBABr), tetrabutylammonium tetrafluoroborate (TBABF(4)), and tetrabutylammonium hexafluorophosphate (TBAPF(6)), were incorporated into [6,6]-phenyl-C-61 butyric acid methyl ester (PCBM) as electron transporting layer (ETL). These salts-doped PCBM films revealed higher electron mobility and Fermi levels compared with the un-doped one. Better charge transfer at the interface between perovskite and salts-doped PCBM was also obtained from PL quenching experiments. Inverted perovskite solar cells with the configuration of ITO/PEDOT:PSS/CH3NH3PbI3/PCBM + salts/Ag were fabricated, and the J(SC) and FF of devices were significantly enhanced using salts-doped PCBM as ETL. The best device based on TBABF(4)-doped PCBM delivered a power conversion efficiency (PCE) up to 13.41%, which was superior to the one with undoped PCBM layer (PCE = 8.77%). (C) 2016 Elsevier B.V. All rights reserved.
Liquid crystal alignment on zinc oxide nanowire arrays for LCDs applications
(2013-12-02)
Chen, Mu-Zhe
;
Chen, Wei-Sheng
;
Jeng, Shie-Chang
;
Yang, Sheng-Hsiung
;
Chung, Yueh-Feng
The zinc oxide (ZnO) nanowire arrays on the indium tin oxide (ITO) glass substrates were fabricated by using the two-step hydrothermal method. A high transmittance similar to 92% of ZnO nanowire arrays on ITO substrate in the visible region was obtained. It was observed that the liquid crystal (LC) directors were aligned vertically to the (ZnO) nanowire arrays. The properties of ZnO nanowire arrays as vertical liquid crystal (LC) alignment layers and their applications for hybrid-aligned nematic LC modes were investigated in this work. (C)2013 Optical Society of America
Liquid crystal alignment on ZnO nanostructure films
(2016-01-01)
Chung, Yueh-Feng
;
Chen, Mu-Zhe
;
Yang, Sheng-Hsiung
;
Jeng, Shie-Chang
;
光電系統研究所
The study of liquid crystal (LC) alignment is important for fundamental researches and industrial applications. The tunable pretilt angles of liquid crystal (LC) molecules aligned on the inorganic zinc oxide (ZnO) nanostructure films with controllable surface wettability are demonstrated in this work. The ZnO nanostructure films are deposited on the ITO-glass substrates by the two-steps hydrothermal process, and their wettability can be modified by annealing. Our experimental results show that the pretilt angles of LCs on ZnO nanostructure films can be successfully adjusted over a wide range from similar to 90 degrees to similar to 0 degrees as the surface energy on the ZnO nanostructure films changes from similar to 30 to similar to 70 mJ/m. Finally, we have applied this technique to fabricate a no-bias optically-compensated bend (OCB) LCD with ZnO nanostructure films annealed at 235 degrees C.
Liquid Crystalline Conjugated Polymers and Their Applications in Organic Electronics
(2009-06-01)
Yang, Sheng-Hsiung
;
Hsu, Chain-Shu
;
應用化學系
;
Department of Applied Chemistry
This article describes the syntheses and electro-optical applications of liquid crystalline (LC) conjugated polymers, for example, poly(p-phenylenevinylene), polyfluorene, polythiophene, and other conjugated polymers. The polymerization involves several mechanisms: the Gilch route, Heck coupling, or Knoevenagel condensation for poly(p-phenylenevinylene)s, the Suzukior Yamamoto-coupling reaction for polyfluorenes, and miscellaneous coupling reactions for other conjugated polymers. These LC conjugated polymers are classified into two types: conjugated main chain polymers with long alkyl side chains, namely main-chain type LC polymers, and conjugated polymers grafting with mesogenic side groups, namely side-chain type LC conjugated polymers. In general, the former shows higher transition temperature and only nematic phase: the latter possesses lower transition temperature and more mesophases, for example. smectic and nematic phases, depending on the structure of mesogenic side chains. The fully conjugated main chain promises them as good candidates for polarized electroluminescent or field-effect devices. The polarized emission can be obtained by surface rubbing or thermal annealing in liquid crystalline phase, with maximum dichroic ratio more than 20. In addition, conjugated oligomers with LC properties are also included and discussed in this article. Several oligo-fluorene derivatives show outstanding polarized emission properties and potential use in LCD backlight application. (c) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47:2713-2733, 2009
Method for debonding of thin glass substrate and carrier for manufacturing thin flexible displays
(2018-11-01)
Chen, Ju-Te
;
Yang, Sheng-Hsiung
;
照明與能源光電研究所
;
Institute of Lighting and Energy Photonics
Modern displays are becoming light, thin, and even curved and flexible. The thickness of glass substrates used in these displays has been reduced from its original value of 1.1 to 0.7mm and eventually to 0.5mm to create thinner displays. Glass substrates with a thickness of <0.3mm are extremely thin and fragile, can be easily deformed, and are therefore not suitable for direct incorporation into the display-manufacturing process. Glass-substrate suppliers bond thin glass substrates onto carrier glass substrates to form laminated glass substrates with increased overall thickness. The panel makers then manufacture the display on a laminated glass substrate. The carrier substrate is removed from the display to produce a thin panel. Glass-substrate makers debond the carrier from the thin glass substrate by applying mechanical force. However, the substrate may break during this debonding process. In this study, a novel method for bonding and debonding the carrier and glass substrates is proposed in which gas is injected between the carrier and thin glass substrate to separate them. This method effectively prevents the formation of edge defects in the thin glass substrate caused by breaks during the debonding process. We designed a debonding machine and established steps to debond the laminated glass substrate after a passive matrix organic light-emitting diode fabrication process. The results showed that this method can be used to efficiently debond the laminated glass substrate.
Nano Approach Investigation of the Conduction Mechanism in Polyaniline Nanofibers
(2011-02-01)
Lin, Yen-Fu
;
Chen, Chien-Hsiang
;
Xie, Wen-Jia
;
Yang, Sheng-Hsiung
;
Hsu, Chain-Shu
A nanotechnological approach is applied to measurements of the electric field dependence of resistance under a high electric field while in low voltage. With this technique, the conduction mechanism on a mesoscopic scale is explored in a single, nonagglomerated nanofiber. Polyaniline nanofibers are prepared by vigorous mixing of aniline and oxidation agent ammonium persulfate in acid solution. They exhibit a uniform nanoscale morphology rather than agglomeration as that produced via conventional chemical oxidation. The as-synthesized polyaniline nanofibers are doped (dedoped) with a HCl acid (NH(3) base), and their temperature behaviors of resistances follow an exponential function with an exponent of T(-1/2). To measure the conduction mechanism in a single nanofiber, the dieiectrophoresis technique is implemented to position nanofibers on top of two electrodes with a nanogap of 100-600 nm, patterned by electron-beam lithography. After the devices are irradiated by electron beam to reduce contact resistances, their temperature behaviors and electric field dependences are unveiled. The experimental results agree well with the theoretical model of charging energy limited tunneling. Other theoretical models such as Efros-Shklovskii and Mott's one-dimensional hopping conduction are excluded after comparisons and arguments. Through fitting, the size of the conductive grain, separation distance between two grains, and charging energy per grain in a single polyaniline nanofiber are estimated to be about 4.9 nm, 2.8 nm, and 78 meV, respectively. The nanotechnological approach, where the nanogap and the dielectrophoresis technique are used for single nanofiber device fabrication, Is applied for determination of mesoscopic charge transport in a polyaniline conducting polymer.
Novel dendritic light-emitting materials containing polyhedral oligomeric silsesquioxanes core
(2006-08-30)
Chen, Kuei-Bai
;
Chang, Yueh-Ping
;
Yang, Sheng-Hsiung
;
Hsu, Chain-Shu
;
應用化學系
A new series of star-like light-emitting materials (POSS1, POSS2 and POSS3) were synthesized by hydrosilylation of the polyhedral oligomeric silsesquioxane with 4,4'-bis(4-(di-(4-methylphenyl)amino)styryl)-2-(hexan-1-yloxy)-5-(10-undecen-1-yloxy)benzene (Cl), 4,4'-bis [(E)-2-(N-ethylcarbazoyl)ethenyl]-2-(hexan-1-yloxy)-5-(10-undecen-1-yloxy)benzene (C2), and Iridium(III) bis(2-phenylpyridine-C-2-N') (13-teradecenyl acetonate) (0), respectively. All synthesized materials are soluble in common organic solvents, such as chloroform, toluene and 1,2dichloroethane, and exhibit good film-forming properties. Therefore, they can be used to fabricate devices by spin-coating. The aggregation of peripheral chromophores can be prevented by the rigid POSS core. A double-layer, light-emitting diode with the configuration of indium-tin oxide/poly(ethylene 3,4-dioxythiophene)/POSS1/Ca/Al was fabricated using POSS1 as the active layer. The device emitted green light with a maximum brightness of 115 cd/m(2) and a current yield of 0.07 cd/A. When the light-emitting layer is blended with 0.8% electron-transport material, 2-(4'-tert-butylphenyl)-5-(4'-diphenyl)-1,3,4-oxadiazole, the maximum brightness and current yield of the device can reach 1469 cd/m(2) and 0.8 cd/A, respectively. The performance of a POSS2 device with the same device structure can reach 1102 cd/m(2) and 0.88 cd/A. POSS3 is a kind of triplet material and blended with 4,4-NN-dicarbazole-biphenyl as host material, to fabricate the light-emitting device. The maximum brightness and current yield reach 1008 cd/m(2) and 1.04 cd/A, respectively. Blending with 1,3,5-tris(2-N-phenylbenzimi dazolyl)benzene as the hole-blocking, material yields a maximum brightness and current yield of 1172 cd/m(2) and 3.99 cd/A. (c) 2006 Elsevier B.V. All rights reserved.
Novel Green Temporary Bonding and Separation Method for Manufacturing Thin Displays
(2020-01-01)
Chen, Ju-Te
;
Yang, Sheng-Hsiung
;
照明與能源光電研究所
;
Institute of Lighting and Energy Photonics
Owing to the rapidly growing popularity of portable products, there is an increasing demand for lightweight devices with thin displays. Glass substrates contribute substantially to the thickness and weight of display panels, and therefore, it is important to minimize their thickness. However, thin glass substrates are too fragile to be supported on their own and used directly. Thicker glass substrates are therefore used to fabricate display panels, and the substrate thickness is then reduced through etching and surface grinding. This approach is time-consuming, involves the use of highly hazardous chemicals, and produces acidic liquid waste. Thus, countries in which thin panels are produced have experienced severe environmental pollution problems related to their manufacture. In addition to the pollution produced, existing panel-thinning methods cannot satisfy the demand for increasingly thinner panels, and as a result, there is an urgent need for new panel-thinning technologies. This article proposes a novel green temporary bonding and separation method that allows thin glass substrates to be carried to directly produce thin panels. This method makes possible the rapid manufacture of thinner glass display panels for foldable and flexible displays. This method does not use any chemicals and does not produce any polluting waste and thereby contributes to environmental protection.