Structural and morphological tuning of dithienobenzodithiophene-core small molecules for efficient solution processed organic solar cells

The fused dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene (DTBDT) structure was coupled with diketopyrrolopyrrole (DPP) moieties to generate highly planar bis(2,5-bis(2-ethylhexyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione)dithieno[2,3-d:2',3'-d]benzo[1,2-b:4,5-b']dithiophene (DTBDTDPP-EH) and bis(2,5-bis(2-butyloctyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione)dithieno[2,3-d:2',3'-d']benzo[1,2-b:4,5-b']dithiophene (DTBDTDPP-BO) molecules, where the EH and BO stands for 2-ethylhexyl and 2-butyloctyl groups respectively. The morphology of the DTBDTDPP-EH alone or DTBDTDPP-EH:[6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) blend film was controlled using post-thermal annealing at 130 degrees C or addition of 1,8-diiodooctane (DIO) additives. The DIO-additive treatment was more effective than thermal annealing at increasing crystallinity; the DIOadditives promoted the formation of nanoscopically well-connected molecular crystalline domains in the blend films. This observation well explained the ordering of the photovoltaic properties of DTBDTDPP-EH:PCBM devices: from worst to best, as-cast, thermally treated, and DIO-treated photoactive films. The DTBDTDPP-BO:PCBM device followed the similar trend with lower performances due to the presence of irregularly overgrown domains. Overall, we demonstrate that it is critical to optimize nanoscale film morphologies by engineering alkyl chains and selecting an appropriate processing method

Influence of Cation Substitutions Based on ABO₃ Perovskite Materials, Sr_1–<i>x</i>Y_<i>x</i>Ti_1–<i>y</i>Ru_<i>y</i>O_3−δ, on Ammonia Dehydrogenation

In order to screen potential catalytic materials for synthesis and decomposition of ammonia, a series of ABO₃ perovskite materials, Sr_1–<i>x</i>Y_<i>x</i>Ti_1–<i>y</i>Ru_<i>y</i>O_3−δ (<i>x</i> = 0, 0.08, and 0.16; <i>y</i> = 0, 0.04, 0.07, 0.12, 0.17, and 0.26) were synthesized and tested for ammonia dehydrogenation. The influence of A or B site substitution on the catalytic ammonia dehydrogenation activity was determined by varying the quantity of either A or B site cation, producing <b>Sr</b>_{<b>1</b>–<b><i>x</i></b>}<b>Y</b>_{<b><i>x</i></b>}Ti_0.92Ru_0.08O_3−δ and Sr_0.92Y_0.08<b>Ti</b>_{<b>1</b>–<i><b>y</b></i>}<b>Ru</b>_{<b><i>y</i></b>}O_3−δ, respectively. Characterizations of the as-synthesized materials using different analytical techniques indicated that a new perovskite phase of SrRuO₃ was produced upon addition of large amounts of Ru (≥12 mol %), and the surface Ru⁰ species were formed simultaneously to ultimately yield <b>Ru</b>_{<b><i>z</i></b>}(surface)/Sr_0.92Y_0.08<b>Ti</b>_{<b>1</b>–<b><i>y</i></b>}<b>Ru</b>_{<i><b>y</b></i>–<b><i>z</i></b>}O_3−δ and/or <b>Ru</b>_{<b><i>z</i></b>–<b><i>w</i></b>}(surface)/Sr_<i>w</i>Ru_<i>w</i>O₃/Sr_{0.92–<i>w</i>}Y_0.08<b>Ti</b>_{<b>1</b>–<b><i>y</i></b>}<b>Ru</b>_{<b><i>y</i></b>–<b><i>z</i></b>}O_3−δ. The newly generated surface Ru⁰ species at the perovskite surfaces accelerated ammonia dehydrogenation under different conditions, and Sr_0.84Y_0.16Ti_0.92Ru_0.08O_3−δ exhibited a NH₃ conversion of ca. 96% at 500 °C with a gas hourly space velocity (GHSV) of 10 000 mL g_cat^–1 h^–1. In addition, Sr_0.84Y_0.16Ti_0.92Ru_0.08O_3−δ further proved to be highly active and stable toward ammonia decomposition at different reaction temperatures and GHSVs for >275 h

High Crystalline Dithienosilole-Cored Small Molecule Semiconductor for Ambipolar Transistor and Nonvolatile Memory

We characterized the electrical properties of a field-effect transistor (FET) and a nonvolatile memory device based on a solution-processable low bandgap small molecule, Si1TDPP-EE-C6. The small molecule consisted of electron-rich thiophene-dithienosilole-thiophene (Si1T) units and electron-deficient diketopyrrolopyrrole (DPP) units. The as-spun Si1TDPP-EE-C6 FET device exhibited ambipolar transport properties with a hole mobility of 7.3 × 10^–5 cm²/(V s) and an electron mobility of 1.6 × 10^–5 cm²/(V s). Thermal annealing at 110 °C led to a significant increase in carrier mobility, with hole and electron mobilities of 3.7 × 10^–3 and 5.1 × 10^–4 cm²/(Vs), respectively. This improvement is strongly correlated with the increased film crystallinity and reduced π–π intermolecular stacking distance upon thermal annealing, revealed by grazing incidence X-ray diffraction (GIXD) and atomic force microscopy (AFM) measurements. In addition, nonvolatile memory devices based on Si1TDPP-EE-C6 were successfully fabricated by incorporating Au nanoparticles (AuNPs) as charge trapping sites at the interface between the silicon oxide (SiO₂) and cross-linked poly­(4-vinylphenol) (<i>c</i>PVP) dielectrics. The device exhibited reliable nonvolatile memory characteristics, including a wide memory window of 98 V, a high on/off-current ratio of 1 × 10³, and good electrical reliability. Overall, we demonstrate that donor–acceptor-type small molecules are a potentially important class of materials for ambipolar FETs and nonvolatile memory applications

Shared genetic architectures of subjective well-being in East Asian and European ancestry populations

Subjective well-being (SWB) has been explored in European ancestral populations; however, whether the SWB genetic architecture is shared across populations remains unclear. We conducted a cross-population genome-wide association study for SWB using samples from Korean (n = 110,919) and European (n = 563,176) ancestries. Five ancestry-specific loci and twelve cross-ancestry significant genomic loci were identified. One novel locus (rs12298541 near HMGA2) associated with SWB was also identified through the European meta-analysis. Significant cross-ancestry genetic correlation for SWB between samples was observed. Polygenic risk analysis in an independent Korean cohort (n = 22,455) demonstrated transferability between populations. Significant correlations between SWB and major depressive disorder, and significant enrichment of central nervous system-related polymorphisms heritability in both ancestry populations were found. Hence, large-scale cross-ancestry genome-wide association studies can advance our understanding of SWB genetic architecture and mental health

Earlier-Phased Cancer Immunity Cycle Strongly Influences Cancer Immunity in Operable Never-Smoker Lung Adenocarcinoma

Exome and transcriptome analyses of clinically homogeneous early-stage never -smoker female patients with lung adenocarcinoma were performed to under-stand tumor-T cell interactions and immune escape points. Using our novel gene panels of eight functional categories in the cancer-immunity cycle, three distinct subgroups were identified in this immune checkpoint blockade-refractory cohort by defective gene expression in two major domains, i.e., type I interferon production/signaling pathway and antigen-presenting machinery. Our approach could play a critical role in understanding immune evasion mechanisms, devel-oping a method for effective selection of rare immune checkpoint blockade re-sponders, and finding new treatment strategies.Y

Nanoscopic Management of Molecular Packing and Orientation of Small Molecules by a Combination of Linear and Branched Alkyl Side Chains

We synthesized a series of acceptor–donor–acceptor-type small molecules (SIDPP-EE, SIDPP-EO, SIDPP-OE, and SIDPP-OO) consisting of a dithienosilole (SI) electron-donating moiety and two diketopyrrolopyrrole (DPP) electron-withdrawing moieties each bearing linear <i>n</i>-octyl (O) and/or branched 2-ethylhexyl (E) alkyl side chains. X-ray diffraction patterns revealed that SIDPP-EE and SIDPP-EO films were highly crystalline with pronounced edge-on orientation, whereas SIDPP-OE and SIDPP-OO films were less crystalline with a radial distribution of molecular orientations. Near-edge X-ray absorption fine structure spectroscopy disclosed an edge-on orientation with a molecular backbone tilt angle of ∼22° for both SIDPP-EE and SIDPP-EO. Our analysis of the molecular packing and orientation indicated that the shorter 2-ethylhexyl groups on the SI core promote tight π–π stacking of the molecular backbone, whereas <i>n</i>-octyl groups on the SI core hinder close π–π stacking to some degree. Conversely, the longer linear <i>n</i>-octyl groups on the DPP arms facilitate close intermolecular packing <i>via</i> octyl–octyl interdigitation. Quantum mechanics/molecular mechanics molecular dynamics simulations determined the optimal three-dimensional positions of the flexible alkyl side chains of the SI and DPP units, which elucidates the structural cause of the molecular packing and orientation explicitly. The alkyl-chain-dependent molecular stacking significantly affected the electrical properties of the molecular films. The edge-on oriented molecules showed high hole mobilities in organic field-effect transistors, while the radially oriented molecules exhibited high photovoltaic properties in organic photovoltaic cells. These results demonstrate that appropriate positioning of alkyl side chains can modulate crystallinity and molecular orientation in SIDPP films, which ultimately have a profound impact on carrier transport and photovoltaic performance