New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Investigation of Organic Conjugated Materials to Understand the Structure-Property Relationships for High-Performance Organic Electronics

School of Energy and Chemical Engineering (Energy Engineering)Since the time when conjugated materials were found to have semiconducting properties with the p-orbital overlapping through the backbone, there have been a lot of research to develop high-performing materials for organic electronic applications, such as organic photovoltaics (OPVs), organic light emitting diodes (OLEDs), and organic field-effect transistors (OFETs) with the advantages of light weight, mechanical flexibility, structural versatility, and facile manufacture with easy solution processing, regarding the energy level, bandgap and the charge transporting behaviors. In OFET system, the factors to obtain a high performance are turned out to be (1) proper energy level placements allowing a spontaneous charge flow between electrode and semiconducting materials used in the system, (2) effective intramolecular charge transfer by utilizing a push-pull architecture and an longer effective p-orbital overlapping between the building blocks in a conjugated backbone, (3) favorable intermolecular interactions affording effective intermolecular transport through the ??-stacked system and good processability, (4) favorable morphological and (5) microstructural characteristics of the films to allow a good interlayer compatibility and satisfy an optimal crystallinity and crystalline orientation. With the structural versatility and tunability of organic materials, it is important to understand how structural factors of conjugated materials govern the molecular properties related to the device performance and charge transport behaviors for a logical design of high-performing organic semiconductors in electronic applications with desirable characteristics. Therefore, in this dissertation, I tried to figure out the relationships between the factors governing the device performance and charge transport behatiors listed above and molecular structures by assigning structural variationsthe first chapter is about the energy level alignment to develop n-type materials by utilizing building blocks considering the electorn-accepting ability, the second chapter regards intermolecular interactions of conjugated materials to enhance noncovalent interactions or solution processability, and the last chapter introduces how regiochemistry can affect the intramolecular charge transfer, film morphology and microstructural characteristics. These findings can be integrated to establish molecular design strategies for high-performance OFETs, and further utilized to expand the application to OPVs and Li+-ion battery system.clos

Usefulness of Polar and Bulky Phosphonate Chain-End Solubilizing Groups in Polymeric Semiconductors

A series of highly soluble copolymers (EH4P-Th, EH4P-Se, EH4P-TT, and EH4P-BT) based on phosphonate chain-end functionalized diketopyrrolopyrrole monomer and four different counterpart comonomers with varied electron-donating strength and conjugation length have been synthesized, characterized, and used in pchannel organic field-effect transistors (OFETs). It was found that introducing different counterpart comonomers into the main backbone alters the copolymers&apos; intrinsic properties, including absorption, frontier energy levels, molecular microstructure, and charge transport in OFETs. In OFETs fabricated on n-octadecyltrimethoxysilane (OTS)-treated silicon (Si)/silicon dioxide (SiO2) surfaces, the copolymers exhibit good hole transport with maximum hole mobility (mu h) of 1.46 x 10-1 cm2 V-1 s-1 in EH4P-TT, which is attributed to edge-on packing, fibrillar intercalating networks, and large crystalline pi stacking. More intriguing is the fact that high solubility and polarity of the resulting copolymers are induced via polar and bulky phosphonate chain-end groups, allowing for proper OFET operation using not only OTS-untreated Si/SiO2 substrates but also an eco-friendly 2-methyltetrahydrofuran solution process. These results demonstrate promising applications of phosphonate chain-end groups in the design of conjugated polymers for various purposes

Effect of Third Component on Efficiency and Stability in Ternary Organic Solar Cells: More than a Simple Superposition

Ternary organic solar cells (OSCs) have attracted much attention due to them being high-performance solar cells. Ternary OSCs represent an efficient strategy to gain both the benefits of enhanced photon energy harvesting using multiple organic materials, similar to that in tandem OSCs, and the easy fabrication of simple single-junction device structures. The properties of ternary OSCs are closely related to their complex energy/charge dynamics mechanisms and unique thermodynamic features of blend morphology and crystallinity. Hence, there is much more to introducing a third component into a binary blend than the simple superposition of individual components. Herein, the role of the third component is mainly discussed to provide in-depth insights into ternary OSCs. This review categorizes and describes the effects that the role and function of the third component have on the efficiency and stability of ternary OSCs. Finally, in addition to a summary on the current research progress, outlooks for future research directions are also addressed

Ternary Solar Cells with a Mixed Face-On and Edge-On Enable an Unprecedented Efficiency of 12.1%

Ternary organic solar cells (OSCs), with a simple structure, can be easily adopted as sub-cells in a tandem design, thereby further enhancing the power conversion efficiency (PCE). Considering the potential to surpass the theoretical PCE limit in OSCs, we incorporated a benzo[1,2-b;4,5-b&apos;]dithiophene-based small molecule into a poly(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b&apos;]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)):[6,6]-phenyl-C71-butyric acid methyl ester host system. A hitherto unrealized PCE of 12.1% was achieved at the optimized composition of the ternary blend. The ternary blend surprisingly had a face-on and edge-on co-existent texture, which is far better than that of the face-on orientated host film. To the best of our knowledge, this intriguing result refutes for the first time a general paradigm that high-performance OSCs are unambiguously linked to face-on structures. Therefore, our study provides a new platform for refining the theoretical underpinning of multiple blending OSCs.clos

Bioderived and Eco-Friendly Solvent-Processed High-Mobility Ambipolar Plastic Transistors through Controlled Irregularity of the Polymer Backbone

The development of top-performing pi-conjugated polymers that can provide good solubility and processability in nontoxic solvents is imperative for the advancement of organic electronic devices. Herein, we report eco-friendly solution-processable semiconducting copolymers prepared by using two dithienylvinylene (TVT) and selenophene (Se) donor units in conjugation with diketopyrrolopyrrole (DPP) as an acceptor moiety. A series of the copolymers are fabricated with different TVT to Se composition ratios present in the DPP backbone that are represented by [10-0], [7-3], [5-5], [3-7], [2-8], [1-9], and [0-10]. Detailed structure-property investigations covering optical, electrochemical, morphological, and charge-transport properties with respect to the TVT/Se ratio in the copolymers are performed by a series of structural characterization techniques. The best ambipolar charge transport is obtained from [3-7] for which the hole mobility (mu(h)) is 6.31 cm(2) V-1 s(-1) and the electron mobility (mu(e)) is 0.78 cm(2) V-1 s(-1). Moreover, high mu(h) and, mu(c) values of 4.15 and 0.34 cm(2) V-1 s(-1), respectively, are achieved for [3-7] devices processed from a bioderived, eco-friendly 2-methyltetrahydrofuran solvent. To the best of our knowledge, these are the highest recorded hole and electron mobilities for ambipolar organic field-effect transistors fabricated from a nonchlorinated solvent to date. Thus, this work is an important scientific step toward developing highly efficient green plastic transistors

Effect of pre-aggregation in conjugated polymer solution on performance of diketopyrrolopyrrole-based organic field-effect transistors

In this work, we investigate the effect of pre-aggregated solutions of diketopyrrolopyrrole (DPP)-based conjugated polymers to achieve highly-aligned polymer films for high-performance organic field-effect transistors (OFETs). A suitable marginal solvent is selected for 5-octyl-pentadecyl branched DPP and selenophene-based semiconducting polymer (PDPP(SE)-epsilon-C8C15) by utilizing the Hansen solubility parameter calculation. The anisotropic one-dimensional aligned PDPP(SE)-epsilon-C8C15 film was off-center spin-coated from the pre-aggregated solution is studied by atomic force microscopy and polarized UV-Vis absorption spectroscopy. A significantly high hole mobility of 4.16 cm(2)V(-1)s(-1) was achieved from the OFETs with a unidirectionally-aligned PDPP(SE)-epsilon-C8C15 film to the transistor channel direction

Ambipolar Passivated Back Surface Field Layer for Silicon Photovoltaics

The suppression of surface recombination is of primary importance for realizing efficient silicon photovoltaics, which is usually achieved by introducing passivation or back-surface field (BSF) layers. In this study, it is demonstrated for the first time that self-assembled, ferroelectric, and organic thin-films can be used as passivating BSF layers for both n- and p-type Si solar cells by switching polarization. The n-Si/PEDOT:PSS heterojunction solar cell with the ambipolar passivated BSF exhibits an efficiency of 18.37%, which is a record-high efficiency for organic semiconductor/n-Si heterojunction solar cells. In addition, homojunction p-Si solar cells with the ambipolar passivated BSF yield superior performance compared to aluminium-BSF cells. Finite-difference time-domain simulations reveal that the electric field due to the ferroelectric layer extends deep into the backside of Si, causing band bending and, consequently, reducing surface recombination. Moreover, the solar cell with passivated BSF maintains &gt; 95% of its initial performance even after 1000 h of the standard damp heat test. This work endows Si-based photovoltaics with the superior passivation and high-performance which were previously exclusive to inorganics

High performance p-type chlorinated-benzothiadiazole-based polymer electrolyte gated organic field-effect transistors

We report the evaluation of charge transport parameters of four p-type dichlorinated-2,1,3-benzothiadiazole (2ClBT) based conjugated polymers end-capped with different electron-donor units (thiophene (T), thieno[3,2-b] thiophene (TT), 2,2&apos;-bithiophene (DT), and (E)-2-(2-(thiophen-2-yl) vinyl) thiophene (TVT)) in electrolyte gated organic field-effect transistors operating at a driving voltage of -2V. Remarkable hole mobility improvement of 0.13-0.56 cm(2)V(-1)s(-1) were achieved in 2ClBTs based polymers, with P2ClBT-DT recording the highest mobility of 0.56 cm(2)V(-1)s(-1) and current on/off ratio similar to 10(7). Interestingly, a positive threshold voltage shift (Delta V-Th) was observed in the transfer characteristics from the linear to saturation regime of all the 2ClBTs based polymer electrolyte gated OFET devices of L = 10 mu m, contrary to devices with conventional poly(methyl methacrylate) gate dielectric, which showed a negative.V-Th shift. Among the 2ClBTs based polymers, P2ClBT-TVT devices showed the lowest mobility and.V-Th shift, which is attributed to severe ion diffusion in the polymer semiconducting layer owing to the vinyl group backbone susceptible to electrochemical doping. Our results emphasize essential selection consideration of the monomeric moieties, molecular ordering, pi-pi stacking and backbone planarity of conjugated polymers for electrolyte based organic devices