Publications by authors named "You-Hao Yang"

The charge transport properties of conjugated polymers are commonly limited by the energetic disorder. Recently, several amorphous conjugated polymers with planar backbone conformations and low energetic disorder have been investigated for applications in field-effect transistors and thermoelectrics. However, there is a lack of strategy to finely tune the interchain π-π contacts of these polymers that severely restricts the energetic disorder of interchain charge transport.

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Solution-processable highly conductive polymers are of great interest in emerging electronic applications. For p-doped polymers, conductivities as high a nearly 10 S cm have been reported. In the case of n-doped polymers, they often fall well short of the high values noted above, which might be achievable, if much higher charge-carrier mobilities determined could be realized in combination with high charge-carrier densities.

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The low n-doping efficiency of conjugated polymers with the molecular dopants limits their availability in electrical conductivity, thermoelectrics, and other electric applications. Recently, considerable efforts have focused on improving the ionization of dopants by modifying the structures of host polymers or n-dopants; however, the effect of ionized dopants on the electrical conductivity and thermoelectric performance of the polymers is still a puzzle. Herein, we try to reveal the role of molecular dopant cations on carrier transport through the systematic comparison of two n-dopants, TAM and -DMBI-H.

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Low n-doping efficiency and inferior stability restrict the thermoelectric performance of n-type conjugated polymers, making their performance lag far behind of their p-type counterparts. Reported here are two rigid coplanar poly(p-phenylene vinylene) (PPV) derivatives, LPPV-1 and LPPV-2, which show nearly torsion-free backbones. The fused electron-deficient rigid structures endow the derivatives with less conformational disorder and low-lying lowest unoccupied molecular orbital (LUMO) levels, down to -4.

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Exceptionally high hydrogen permselectivity, exceeding that of any polymeric or porous inorganic systems, is achieved using an ionically crosslinked multilayer polymer thin film.

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Super gas barrier thin films, fabricated with layer-by-layer assembly of polyethylenimine and graphene oxide, exhibit significantly reduced oxygen and carbon dioxide transmission rates. This thin film's nanobrick wall structure also provides high gas selectivity for hydrogen.

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