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Donor-acceptor polymer-fullerene-based bulk heterojunction (BHJ) photovoltaic cells have many advantages; specifi cally, they can be fabricated in large-areas with simple solution methods involving a low-cost roll-to-roll manufacturing process. [1][2][3][4][5][6][7] The active layer in BHJ solar cells provides charge generation, separation, transport, and collection. During these steps, sweep-out of photo-generated carriers competes with charge recombination within the BHJ due to low carrier mobility. [8][9][10] Blocking the recombination is a key method of increasing device efficiency. [ 11 ] Therefore, we need to decrease the thickness of the active layer of BHJ fi lm and maximize its absorption capability to reduce the likelihood of recombination and thereby improve the effi ciency of the device.Metallic silver (Ag) nanoparticles (NPs) can be effective in thin fi lm solar cells because of their localized surface plasmon resonance, which can increase the light absorption capability of an active layer within a range of wavelengths. Thus, the addition of metal NPs into a BHJ active layer can potentially enhance the absorption and increase the photo-generation of mobile carriers. Several groups have recently reported that, when combined, polymer and metal NPs improve light absorption and cell effi ciency. [12][13][14][15] To ensure that metal NPs have positive effects in organic photovoltaic devices (OPVs), we must diminish the possibility of transferring nonradiative energy, which quenches excitons in the BHJ active layer. [ 12 , 15 ] Because of this concern, most researchers add metal NPs to the interface of the indium tin oxide (ITO) anode and the BHJ active layer; alternatively, they embed the metal NPs in a poly(3,4-ethylene dioxythiophene:poly(styrene sulfonate) (PEDOT:PSS) hole transporting interlayer to induce plasmon excitation within the thin BHJ fi lm. [ 12 , 16 , 17 ] However, Kim and Carroll directly added Ag or Au NPs to a BHJ polymer and confi rmed that the cell effi ciency was enhanced by the improved electrical conductivity. [ 13 ] The simple method of directly mixing metal NPs in an active layer is attractive because it enhances the overall performance of the cell. Specifi cally, this method can reduce the device resistance; [ 13 ] furthermore, the incident light can be refl ected and scattered by the embedded metal NPs while passing through the active layer, thereby increasing the optical path length of the incident light.Our study demonstrates several positive effects that arise from the addition of Ag NPs with controlled diameter size in BHJ photovoltaic cells fabricated with poly[N-9"-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole) (PCDTBT)/ [6,6]-phenyl C 70 butyric acid methyl-ester (PC 70 BM). Using effective, easily processable solution chemistry of a polyol process, we can synthesize Ag particles with wellcontrolled sizes and well-defi ned shapes. Specifi cally, we produced particles with diameters of 30 nm, 40 nm, and 60 nm. These Ag NPs have differe...

Order/disorder interfacial engineering realizes highly efficient co-catalyst free hydrogen generation.

Recently, polymer−fullerene based bulk heterojunction (BHJ) solar cells, which contain blends of poly ({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl}) (PTB7) and [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM), have been widely studied due to exhibiting high power conversion efficiency (PCE) and well-defined nanomorphology. Because of the short exciton diffusion pathway (less than 10 nm) in organic thin films, the optimization of PTB7:PC 71 BM BHJ with optimized morphology is very important between the donor and acceptor. In order to increase nanoscale phase separation, the chemical additives of 1,8-diiodooctane (DIO) have been used in PTB7:PC 71 BM blend systems. However, the mechanism studies of DIO in BHJ solar cells and its effectiveness on device stability are unclear. In this study, we fabricated polymer solar cells (PSCs) based on PTB7:PC 71 BM BHJ with various DIO concentrations to investigate not only correlation between device performances and different morphologies, but also the influence of additives on device stabilities. Positive effects of DIO, which were induced by efficient charge separation in BHJ at optimized blending ratio, are proved by the results of time-resolved photoluminescence (TRPL), and negative effects of DIO on a device stability have been investigated according to the ISOS-D-1 protocol.

The current study proposed and tested a theoretical model of consumers' online brand community engagement behaviors, with particular attention given to online brand community type (consumer vs. marketer-created). By integrating attribution and social identity theories, this study investigated the causal linkages between intrinsic motives of altruism, social identification motivations, and online brand community engagement behaviors. The results showed that consumers' online brand community engagement intentions were indirectly influenced by the different types of communities through different levels of consumers' attributions to intrinsic motives of altruism. This study also found that, in the attribution processes, consumers' intrinsic motives of altruism motivated them to identify themselves socially with the online communities they join. Finally, this study demonstrated that the intrinsic motives of altruism and social identification motivations provided strong social incentives to motivate consumers to engage in subsequent online brand community behaviors.