Thin film transistors （TFTs） of microcrystalline silicon （μc-Si） can provide higher mobility and stability than that of a-Si and better uniformity than that of poly-Si TFTs, and it would be more suitable to be ap...Thin film transistors （TFTs） of microcrystalline silicon （μc-Si） can provide higher mobility and stability than that of a-Si and better uniformity than that of poly-Si TFTs, and it would be more suitable to be applied to larger-area AMOLEDs. By using 2coYAG laser ann. ealing, crystalline μc-Si thin film on plastic substrate has been investigated and the proper laser energy needed for crystallization has been indicated. It has been found that the dehydrogenation process at 300-450℃ for a few of hours could be omitted by decreasing the H content in the crystallization precursor, which is suitable for laser crystallization on plastic substrates. The crystalline volume fraction （Xc） and the grain size of the resulted μc-Si could be adjusted by controlling the laser energy. By this method, the μc-Si on plastic substrate with Xc and grain size is respectively 85% （at the maximum） and 50 nm.展开更多
New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotri...New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3 and 6 with 1-heptyne and 1-octyne have been achieved with WCl6- and TaCl5-Ph4Sn catalysts, respectively, giving soluble linear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2 x 10(5)) in high yields (up to 98%). The structures and properties of the polymers are characterized and evaluated by R NMR, TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stability and emit strong blue light upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL was observed in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has been achieved in 2, which are the best results for substituted polyacetylenes attainable so far.展开更多
By melting tetraphenylethene （TPE） and 1,2,4,5-tetraphenyl-lH-imidazole （TPI） units together through different linking positions, three new fluorophores are synthesized, and their optical, electronic and electro- ...By melting tetraphenylethene （TPE） and 1,2,4,5-tetraphenyl-lH-imidazole （TPI） units together through different linking positions, three new fluorophores are synthesized, and their optical, electronic and electro- luminescence （EL） properties are fully studied. Owing to the presence of TPE unit（s）, these fluorophores are weak emitters in solutions, but are induced to emit strongly in the aggregated state, presenting typical aggregation-induced emission characteristics. The experimental and computational results reveal that different connection patterns between TPE and TPI could impact the molecular conjugation greatly, leading to varied emission wavelength, fluorescence quantum yield and EL performance in organic light emitting diodes （OLEDs）. The fluorophore built by attaching TPE unit to the 1-position of imidazole ring shows bluest fluorescence, and its EL device emits at deep blue region （445 nm; CIE= （0.16, 0.15））. And the device based on the fluorophore by linking TPE to the 2- position of imidazole ring shows EL at 467 nm （CIE= （0.17, 0.22）） with good efficiencies of 3.17 cd.A ^-1, and 1.77%.展开更多
A technique to improve and accelerate aluminum induced crystallization（AIC） by using hydrogen plasma is proposed.Raman spectroscopy and secondary ion mass spectrometry of crystallized poly-Si thin films show that hy...A technique to improve and accelerate aluminum induced crystallization（AIC） by using hydrogen plasma is proposed.Raman spectroscopy and secondary ion mass spectrometry of crystallized poly-Si thin films show that hydrogen plasma radicals reduce the crystallization time of AIC.This technique shortens the annealing time from 10 to 4 h and increases the Hall mobility from 22.1 to 42.5 cm^2/（V·s）.The possible mechanism of AIC assisted by hydrogen radicals is also discussed.展开更多
基金This work has been supported by "863" Project of National Min- istry of Science and Technology (No. 2004AA33570)Key Project of NSFC (No. 60437030)Tianjin Natural Science Founda- tion (No.05YFJMJC01400)
文摘Thin film transistors （TFTs） of microcrystalline silicon （μc-Si） can provide higher mobility and stability than that of a-Si and better uniformity than that of poly-Si TFTs, and it would be more suitable to be applied to larger-area AMOLEDs. By using 2coYAG laser ann. ealing, crystalline μc-Si thin film on plastic substrate has been investigated and the proper laser energy needed for crystallization has been indicated. It has been found that the dehydrogenation process at 300-450℃ for a few of hours could be omitted by decreasing the H content in the crystallization precursor, which is suitable for laser crystallization on plastic substrates. The crystalline volume fraction （Xc） and the grain size of the resulted μc-Si could be adjusted by controlling the laser energy. By this method, the μc-Si on plastic substrate with Xc and grain size is respectively 85% （at the maximum） and 50 nm.
文摘New acetylene monomers, 6-{[(1-naphthylethynyl-4-phenyl)carbonyl]oxy}-1-phenyl-1-hexyne (1), 2,5-diethynyl-thiophene (3), and 4,4'-diethynylbiphenyl (6) were synthesized. Homopolymerization of 1 and copolycyclotrimerizations of 3 and 6 with 1-heptyne and 1-octyne have been achieved with WCl6- and TaCl5-Ph4Sn catalysts, respectively, giving soluble linear disubstituted polyacetylene (2) and hyperbranched polyarylenes (5 and 8) with high molecular weights (up to 1.2 x 10(5)) in high yields (up to 98%). The structures and properties of the polymers are characterized and evaluated by R NMR, TGA, UV, photoluminescence (PL), and electroluminescence (EL) analyses. All the polymers possess high thermal stability and emit strong blue light upon photoexcitation. The intensity of the emitted light is greater than that of poly(1-phenyl-1-octyne), a well-known highly luminescent disubstituted polyacetylene. Little aggregation-induced red shift in the PL was observed in the thin films of the polymers. By constructing a multi-layer EL device, high EL quantum yield (0.18%) has been achieved in 2, which are the best results for substituted polyacetylenes attainable so far.
文摘By melting tetraphenylethene （TPE） and 1,2,4,5-tetraphenyl-lH-imidazole （TPI） units together through different linking positions, three new fluorophores are synthesized, and their optical, electronic and electro- luminescence （EL） properties are fully studied. Owing to the presence of TPE unit（s）, these fluorophores are weak emitters in solutions, but are induced to emit strongly in the aggregated state, presenting typical aggregation-induced emission characteristics. The experimental and computational results reveal that different connection patterns between TPE and TPI could impact the molecular conjugation greatly, leading to varied emission wavelength, fluorescence quantum yield and EL performance in organic light emitting diodes （OLEDs）. The fluorophore built by attaching TPE unit to the 1-position of imidazole ring shows bluest fluorescence, and its EL device emits at deep blue region （445 nm; CIE= （0.16, 0.15））. And the device based on the fluorophore by linking TPE to the 2- position of imidazole ring shows EL at 467 nm （CIE= （0.17, 0.22）） with good efficiencies of 3.17 cd.A ^-1, and 1.77%.
基金supported by the National Natural Science Foundation of China(No.61076006)the National High Technology Research and Development Program of China(No.2008AA03A335)
文摘A technique to improve and accelerate aluminum induced crystallization（AIC） by using hydrogen plasma is proposed.Raman spectroscopy and secondary ion mass spectrometry of crystallized poly-Si thin films show that hydrogen plasma radicals reduce the crystallization time of AIC.This technique shortens the annealing time from 10 to 4 h and increases the Hall mobility from 22.1 to 42.5 cm^2/（V·s）.The possible mechanism of AIC assisted by hydrogen radicals is also discussed.
