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Abstract: We present the results of a systematic study on how the solvent processing affects the EL properties of a single emissive layer white PLED based on a polyfluorene derivative polymer. The EL spectrum of the device using solvent processing, peaked at 436, 572nm, shows a pure white emission and the luminous efficiency is enhanced, which is attributed to the presence of the crystalline polyfluorene induced by solvent processing. The crystalline polyfluorene that acts as the self-dopant enhances the blue emission and increases the purity of the white light. Most importantly, the charge transport is balanced after solvent processing, which favors improving the luminous efficiency. A light-emitting efficiency of 12cd/A is achieved after solvent processing, about 50% increase compared to the as-spincoated device. [Copyright &y& Elsevier]

It is reported a kind of solution-processible transparent conductive film consisting of reduced graphene oxide (rGO) nanosheets and silver nanowires (AgNWs). The sandwiched structure of rGO/AgNWs/rGO is readily deposited via layer-by-layer blade-coating on the rigid glass or flexible PET substrate at mild annealing temperature. The rGO nanosheets sandwiching the AgNWs networks not only induce close contact of the AgNWs networks as a clipper to improve the conductivity, but also link the discrete AgNWs as a connector to improve the uniformity of the film conductivity. The transparent rGO/AgNWs/rGO film exhibits sheet resistance as low as 14.29 Ω/□ with transmittance over 90% at 550 nm. Moreover, the rGO/AgNWs/rGO composite film shows good ambient stability due to the rGO coverage and the existing charge interaction between AgNWs and rGO. Polymer solar cells are fabricated on the transparent rGO/AgNWs/rGO-coated glass or flexible PET substrates and they exhibit comparable photovoltaic perfromance to the control devices fabricated on the commercial ITO substrate. More importantly, the PSCs based on the rGO/AgNWs/rGO/PET substrate show more excellent flexibility than that of the device based on the ITO/PET substrate. [ABSTRACT FROM AUTHOR]

Abstract: Enhanced performances of hybrid polymer solar cells based on a blend of poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and p-methoxybenzoic acid (MBA) modified zinc oxide (ZnO) nanoparticles were reported. Both the short-circuit current and open-circuit voltage of solar cells were improved by using MBA modified ZnO nanoparticles as electron acceptor. The overall power conversion efficiency was increased from 1.09% to 1.52% under AM 1.5G 100mW/cm2 illumination after ZnO was modified with MBA at 0.1wt.%. It was found that modification of ZnO with 0.1wt.% of MBA did not affect electron and hole transport properties of the active layer. However, a fine phase separation between MEH-PPV donor and MBA-modified ZnO acceptor was obtained. The fine phase separation enhanced the exciton dissociation efficiency and hence the power conversion efficiency of solar cells. [Copyright &y& Elsevier]

Abstract: A kind of tandem polymer photovoltaic cell with inorganic metal oxides as a transparent middle connection unit to link the two subcells having different absorption characteristics is developed and its open-circuit voltage origin is investigated. The middle connection unit consists of an electron-transporting titanium oxide (TiO x ) layer, a thin aluminum (Al) layer and a hole-transporting molybdenum oxide (MoO3) layer. The inserted thin Al layer between the TiO x and MoO3 layers not only acts as an efficient recombination site for electrons and holes photo-generated in the two subcells, but also realigns the electronic energy levels at TiO x /MoO3 interfaces to reduce the open-circuit voltage loss. The open-circuit voltage of the tandem cell is the summation of the two subcells. [Copyright &y& Elsevier]