Structure Evolution of Fluorinated Conjugated Polymers Based on Benzodithiophene and Benzothiadiazole for Photovoltaics

Two novel copolymer PTBD­Tff­DC₈­TBT and PTBD­Tff­DC₈­TBT-FB based on alkylthienyl benzodithiophene (TBDT) and fluorinated benzothiadiazole (ffDTBT) blocks were synthesized, and the effects of <i>n</i>-octyl side chains (C₈) on thiophene bridge and pentafluorobenzene (FB) end group on properties of the copolymers has been investigated. With the similar properties of good thermal stability, wide spectral absorption (band gap of 1.68 eV), the molecular energy levels, and the arrangement of the polymer chains, the best pristine power conversion efficiency of PTBD­Tff­DC₈­TBT-FB:PC₆₁BM (1:1) was higher than that of PTBD­Tff­DC₈­TBT, 3.6% versus 2.1%. A more optimal microphase separation morphology of PTBD­Tff­DC₈­TBT-FB:PC₆₁BM was one of the driving force to enhance the short-circuit current density (<i>J</i>_sc) and fill factor (FF), consequently resulting in the improved performance. Comparison of the five analogous polymers was implemented from both experiment measurement and density functional theory simulation in detail. It was demonstrated that the FB end group contributed to promote the molecule dipole moment, which benefit the exciton separation for improvement in the performance

Enhanced Power-Conversion Efficiency in Inverted Bulk Heterojunction Solar Cells using Liquid-Crystal-Conjugated Polyelectrolyte Interlayer

Two novel liquid-crystal-conjugated polyelectrolytes (LCCPEs) poly­[9,9-bis­[6-(4-cyanobiphenyloxy)-hexyl]–fluorene–<i>alt</i>-9,9-bis­(6-(<i>N</i>,<i>N</i>-diethylamino)-hexyl)-fluorene] (PF6Ncbp) and poly­[9,9-bis­[6-(4-cyanobiphenyloxy)-hexyl]–fluorene–<i>alt</i>-9,9-bis­(6-(<i>N</i>-methylimidazole)-hexyl]-fluorene] (PF6lmicbp) are obtained by covalent linkage of the cyanobiphenyl mesogen polar groups onto conjugated polyelectrolytes. After deposition a layer of LCCPEs on ZnO interlayer, the spontaneous orientation of liquid-crystal groups can induce a rearrangement of dipole moments at the interface, subsequently leading to the better energy-level alignment. Moreover, LCCPEs favors intimate interfacial contact between ZnO and the photon harvesting layer and induce active layer to form the nanofibers morphology for the enhancement of charge extraction, transportation and collection. The water/alcohol solubility of the LCCPEs also enables them to be environment-accepted solvent processability. On the basis of these advantages, the poly­(3-hexylthiophene) (P3HT):[6,6]-phenyl-C₆₀-butyric acid methyl ester (PC₆₀BM)-based inverted polymer solar cells (PSCs) combined with ZnO/PF6Ncbp and ZnO/PF6lmicbp bilayers boost the power conversion efficiency (PCE) to 3.9% and 4.2%, respectively. Incorporation of the ZnO/PF6lmicbp into the devices based on a blend of a narrow band gap polymer thieno­[3,4-<i>b</i>]­thiophene/benzodithiophene (PTB7) with [6,6]-phenyl C₇₀-butyric acid methyl ester (PC71BM) affords a notable efficiency of 7.6%

Alcohol-Soluble n‑Type Conjugated Polyelectrolyte as Electron Transport Layer for Polymer Solar Cells

A novel alcohol-soluble n-type conjugated polyelectrolyte (n-CPE) poly-2,5-bis­(2-octyldodecyl)-3,6-bis­(thiophen-2-yl)-pyrrolo­[3,4-<i>c</i>]­pyrrole-1,4-dione-<i>alt</i>-2,5-bis­[6-(<i>N</i>,<i>N</i>,<i>N</i>-trimethyl­ammonium)­hexyl]-3,6-bis­(thiophen-2-yl)-pyrrolo­[3,4-<i>c</i>]­pyrrole-1,4-dione (PDPPNBr) is synthesized for applications as an electron transport layer (ETL) in an inverted polymer solar cells (PSCs) device. Because of the electron-deficient nature of diketopyrrolopyrrole (DPP) backbone and its planar structure, PDPPNBr is endowed with high conductivity and electron mobility. The interfacial dipole moment created by n-CPE PDPPNBr can substantially reduce the work function of ITO and induce a better energy alignment in the device, facilitating electron extraction and decreasing exctions recombination at active layer/cathode interface. As a result, the power conversion efficiency (PCE) of the inverted devices based poly­(3-hexylthiophene) (P3HT):(6,6)-phenyl-C₆₁ butyric acid methyl ester (PC₆₁BM) active layer with PDPPNBr as ETL achieves a value of 4.03%, with 25% improvement than that of the control device with ZnO ETL. Moreover, the universal PDPPNBr ETL also delivers a notable PCE of 8.02% in the devices based on polythieno­[3,4-<i>b</i>]-thiophene-<i>co</i>-benzo­dithiophene (PTB7):(6,6)-phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM). To our best knowledge, this is the first time that n-type conjugated polyelectrolyte-based cathode interlayer is reported. Quite different from the traditional p-type conjugated and nonconjugated polyelectrolytes ETLs, n-CPE PDPPNBr as ETL could function efficiently with a thickness approximate 30 nm because of the high conductivity and electron mobility. Furthermore, the PDPPNBr interlayer also can ensure the device with the improved long-term stability. The successful application of this alcohol solution processed n-type conjugated polyelectrolyte indicates that the electron-deficient planar structure with high electron mobility could be very promising in developing high performance and environmentally friendly polymer solar cells

Prioritizing Candidate Disease Metabolites Based on Global Functional Relationships between Metabolites in the Context of Metabolic Pathways

<div><p>Identification of key metabolites for complex diseases is a challenging task in today's medicine and biology. A special disease is usually caused by the alteration of a series of functional related metabolites having a global influence on the metabolic network. Moreover, the metabolites in the same metabolic pathway are often associated with the same or similar disease. Based on these functional relationships between metabolites in the context of metabolic pathways, we here presented a pathway-based random walk method called PROFANCY for prioritization of candidate disease metabolites. Our strategy not only takes advantage of the global functional relationships between metabolites but also sufficiently exploits the functionally modular nature of metabolic networks. Our approach proved successful in prioritizing known metabolites for 71 diseases with an AUC value of 0.895. We also assessed the performance of PROFANCY on 16 disease classes and found that 4 classes achieved an AUC value over 0.95. To investigate the robustness of the PROFANCY, we repeated all the analyses in two metabolic networks and obtained similar results. Then we applied our approach to Alzheimer's disease (AD) and found that a top ranked candidate was potentially related to AD but had not been reported previously. Furthermore, our method was applicable to prioritize the metabolites from metabolomic profiles of prostate cancer. The PROFANCY could identify prostate cancer related-metabolites that are supported by literatures but not considered to be significantly differential by traditional differential analysis. We also developed a freely accessible web-based and R-based tool at <a href="http://bioinfo.hrbmu.edu.cn/PROFANCY" target="_blank">http://bioinfo.hrbmu.edu.cn/PROFANCY</a>.</p></div

Top ranked prostate cancer candidate metabolites by PROFANCY.

<p>N vs T: normal samples vs localized cancer samples; N vs M: normal samples vs metastatic cancer samples.</p

The state of the sub-networks in response to hydrogen peroxide in segregants inherited alleles from RM and BY.

<p>Solid edges indicate correlated expression between proteins in one allele state, whereas that organization is lost in another allele state (dotted line). Edge colors represent diverse interaction types between proteins, whereas node colors represent changes in gene expression between wild and mutant groups; green denotes down-regulation and red denotes up-regulation. Triangle nodes present genes annotated in ‘ergosterol metabolic process’, ‘lipid biosynthetic process’, and ‘oxidation reduction’. Nodes with dark edges are known drug targets of hydrogen peroxide based on Stitch2 database.</p

The AUC value of 16 disease classes.

<p>FPN = functional pathway nodes.</p

Top ranked candidate metabolites of Alzheimer's disease in the KEGG metabolic network.

<p>The top ranked candidate metabolites of AD are showed in the KEGG metabolic network. The gray, blue and red nodes represent candidate metabolites, known metabolites (seed nodes) and top 1% ranked candidates, respectively. The black boxes represent 6 candidates which ranked in top 10 and their connected functional pathway nodes in both metabolic networks. The right large box shows the pathway of “Valine, leucine and isoleucine degradation” which includes the metabolite (S)-Methylmalonate semialdehyde (arrow pointed).</p

The ROC curve of 7 disease classes and all diseases with or without functional pathway nodes in two metabolic networks.

<p>The ROC curve of 7 disease classes and all diseases with or without functional pathway nodes in two metabolic networks.</p

The changing pattern of molecular networks under allele-specific context determined by LD blocks.

<p>(A) Hierarchical clustering on the perturbed interactions based on the association matrix between blocks and their perturbing interactions in PPI, PDI, KPI, and EEI networks, respectively, in which rows represent blocks and columns represent interactions. In each of the four sub-matrices, blocks associated with less than ten interactions are filtered out. The columns are reordered according to hierarchical clustering. The rows colored correspond to B20. (B) The allele-specific sub-network associated with B20. The sub-network is composed of 142 PPIs, 54 PDIs, 93 KPIs, and 26 EEIs, which are marked with green, red, blue and orange, respectively. Nodes marked with red are proteins constituting a GO cellular component (nuclear lumen), and PPIs among these genes are regulated by B20. Nodes marked with green are enzymes from a KEGG pathway (DNA-directed RNA polymerase activity), and their EEIs are regulated by B20.</p