Miniaturized and High Volumetric Energy Density Power Supply Device Based on a Broad-Frequency Vibration Driven Triboelectric Nanogenerator.

The widespread vibration is one of the most promising energy sources for IoT and small sensors, and broad-frequency vibration energy harvesting is important. Triboelectric nanogenerators (TENGs) can convert vibration energy into electrical energy through triboelectricity and electrostatic induction, providing an effective solution to the collection of broad-frequency vibration energy. Also, the power supply in constrained and compact spaces has been a long-standing challenge. Here, a miniaturized power supply (MPS) based on a broad-frequency vibration-driven triboelectric nanogenerator (TENG) is developed. The size of the MPS is 38 mm × 26 mm × 20 mm, which can adapt to most space-limited environments. The TENG device is optimized through theoretical mechanical modeling for the external stimuli, it can efficiently harvest vibrational energy in the frequency range of 1-100 Hz and has a high output power density of 134.11 W/cm3. The developed device demonstrates its practical application potential in powering small electronics like LEDs, watches, and timers.

Transition metal-catalysed molecular n-doping of organic semiconductors.

Chemical doping is a key process for investigating charge transport in organic semiconductors and improving certain (opto)electronic devices1-9. N(electron)-doping is fundamentally more challenging than p(hole)-doping and typically achieves a very low doping efficiency (η) of less than 10%1,10. An efficient molecular n-dopant should simultaneously exhibit a high reducing power and air stability for broad applicability1,5,6,9,11, which is very challenging. Here we show a general concept of catalysed n-doping of organic semiconductors using air-stable precursor-type molecular dopants. Incorporation of a transition metal (for example, Pt, Au, Pd) as vapour-deposited nanoparticles or solution-processable organometallic complexes (for example, Pd2(dba)3) catalyses the reaction, as assessed by experimental and theoretical evidence, enabling greatly increased η in a much shorter doping time and high electrical conductivities (above 100 S cm-1; ref. 12). This methodology has technological implications for realizing improved semiconductor devices and offers a broad exploration space of ternary systems comprising catalysts, molecular dopants and semiconductors, thus opening new opportunities in n-doping research and applications12, 13.

Teaching an Old Anchoring Group New Tricks: Enabling Low-Cost, Eco-Friendly Hole-Transporting Materials for Efficient and Stable Perovskite Solar Cells.

As a key component in perovskite solar cells (PVSCs), hole-transporting materials (HTMs) have been extensively explored and studied. Aiming to meet the requirements for future commercialization of PVSCs, HTMs which can enable excellent device performance with low cost and eco-friendly processability are urgently needed but rarely reported. In this work, a traditional anchoring group (2-cyanoacrylic acid) widely used in molecules for dye-sensitized solar cells is incorporated into donor-acceptor-type HTMs to afford MPA-BT-CA, which enables effective regulation of the frontier molecular orbital energy levels, interfacial modification of an ITO electrode, efficient defect passivation toward the perovskite layer, and more importantly alcohol solubility. Consequently, inverted PVSCs with this low-cost HTM exhibit excellent device performance with a remarkable power conversion efficiency (PCE) of 21.24% and good long-term stability in ambient conditions. More encouragingly, when processing MPA-BT-CA films with the green solvent ethanol, the corresponding PVSCs also deliver a substantial PCE as high as 20.52% with negligible hysteresis. Such molecular design of anchoring group-based materials represents great progress for developing efficient HTMs which combine the advantages of low cost, eco-friendly processability, and high performance. We believe that such design strategy will pave a new path for the exploration of highly efficient HTMs applicable to commercialization of PVSCs.

Fused Bithiophene Imide Oligomer and Diketopyrrolopyrrole Copolymers for n-Type Thin-Film Transistors.

Diketopyrrolopyrrole (DPP)-based copolymers have received considerable attention as promising semiconducting materials for high-performance organic thin-film transistors (OTFTs). However, these polymers typically exhibit p-type or ambipolar charge-transporting characteristics in OTFTs due to their high-lying highest occupied molecular orbital (HOMO) energy levels. In this work, a new series of DPP-based n-type polymers have been developed by incorporating fused bithiophene imide oligomers (BTIn) into DPP polymers. The resulting copolymers BTIn-DPP show narrow band gaps as low as 1.27 eV and gradually down-shifted frontier molecular orbital energy levels upon the increment of imide group number. Benefiting from the coplanar backbone conformation, well-delocalized π-system, and favorable polymer chain packing, the optimal polymer in the series shows promising n-type charge transport with an electron mobility up to 0.48 cm2 V-1 s-1 in OTFTs, which is among the highest values for the DPP-based n-type polymers reported to date. The results demonstrate that incorporating fused bithiophene imide oligomers into polymers can serve as a promising strategy for constructing high-performance n-type polymeric semiconductors.

A New Wide Bandgap Donor Polymer for Efficient Nonfullerene Organic Solar Cells with a Large Open-Circuit Voltage.

Significant progress has been made in nonfullerene small molecule acceptors (NF-SMAs) that leads to a consistent increase of power conversion efficiency (PCE) of nonfullerene organic solar cells (NF-OSCs). To achieve better compatibility with high-performance NF-SMAs, the direction of molecular design for donor polymers is toward wide bandgap (WBG), tailored properties, and preferentially ecofriendly processability for device fabrication. Here, a weak acceptor unit, methyl 2,5-dibromo-4-fluorothiophene-3-carboxylate (FE-T), is synthesized and copolymerized with benzo[1,2-b:4,5-b']dithiophene (BDT) to afford a series of nonhalogenated solvent processable WBG polymers P1-P3 with a distinct side chain on FE-T. The incorporation of FE-T leads to polymers with a deep highest occupied molecular orbital (HOMO) level of -5.60-5.70 eV, a complementary absorption to NF-SMAs, and a planar molecular conformation. When combined with the narrow bandgap acceptor ITIC-Th, the solar cell based on P1 with the shortest methyl chain on FE-T achieves a PCE of 11.39% with a large V oc of 1.01 V and a J sc of 17.89 mA cm-2. Moreover, a PCE of 12.11% is attained for ternary cells based on WBG P1, narrow bandgap PTB7-Th, and acceptor IEICO-4F. These results demonstrate that the new FE-T is a highly promising acceptor unit to construct WBG polymers for efficient NF-OSCs.

Systemic screening identifies GABRD, a subunit gene of GABAA receptor as a prognostic marker in adult IDH wild-type diffuse low-grade glioma.

Currently, no reliable prognostic biomarkers have been identified for adult IDH wild-type (WT) diffuse low grade glioma (LGG). With data from The Cancer Genome Atlas (TCGA)-LGG, we examined the prognostic value of GABAA receptor subunits in adult IDH WT LGG. Using 2016 WHO CNS tumor classification, we re-classified the TCGA-LGG and identified 95 IDH WT patients. Among 16 GABAA receptor subunit genes with RNA-seq data, eight genes showed significantly different expression in IDH WT LGG compared with IDH mutant (MT) cases. Among these genes, only GABRD expression was related to overall survival (OS) status. Preserved GABRD expression was independently associated with longer OS (HR: 0.799, 95%CI: 0.691-0.925, p = 0.003) in IDH WT LGG. GABRD expression showed a moderately negative correlation with tumor infiltration macrophage (TIM) and CSF1 expression. The methylation status of 34 CpG sites across GABRD gene was checked and only cg13916816 showed a moderately negative correlation with GABRD expression. In conclusion, GABRD expression might serve as a potential independent prognostic marker in patients with IDH WT LGG. Meanwhile, its expression was negatively correlated with the extent of TIM, which might help to explain the favorable survival outcome. Cg13916816 might be a critical CpG site influencing GABRD expression in IDH WT LGG.

Boosting Efficiency and Stability of Organic Solar Cells Using Ultralow-Cost BiOCl Nanoplates as Hole Transporting Layers.

A novel nanomaterial, bismuth oxychloride nanoplates (BiOCl NPs), was first applied in organic solar cells (OSCs) as hole transporting layers (HTLs). It is worth noting that the BiOCl NPs can be facilely synthesized at ∼1/200 of the cost of the commercial PEDOT:PSS and well dissolved in green solvents. Different from the PEDOT:PSS interlayer, the deposition of BiOCl HTL is free of post-treatment at elevated temperature, which reduces device fabrication complexity. To demonstrate the universality of BiOCl in improving photovoltaic performance, OSCs containing various representative active layers were investigated. The power conversion efficiencies (PCEs) of the P3HT:PC61BM, PTB7-Th:PC71BM, and PM6:Y6-based OSCs with the BiOCl HTL boosted from 3.62, 8.78, and 15.63 to 4.24, 9.92, and 16.11%, respectively, compared to the PEDOT:PSS-based ones. It was found that the superior performances of the BiOCl-based OSCs are mainly attributed to the sufficient oxygen vacancies and improved interfacial contact. Moreover, the BiOCl-based OSCs show a much better stability than the cells with the PEDOT:PSS interfacial layer.

Backbone Coplanarity Tuning of 1,4-Di(3-alkoxy-2-thienyl)-2,5-difluorophenylene-Based Wide Bandgap Polymers for Efficient Organic Solar Cells Processed from Nonhalogenated Solvent.

Halogenated solvents are prevailingly used in the fabrication of nonfullerene organic solar cells (NF-OSCs) at the current stage, imposing significant restraints on their practical applications. By copolymerizing phthalimide or thieno[3,4-c]pyrrole-4,6-dione (TPD) with 1,4-di(3-alkoxy-2-thienyl)-2,5-difluorophenylene (DOTFP), which features intramolecular noncovalent interactions, the backbone planarity of the resulting DOTFP-based polymers can be effectively tuned, yielding distinct solubilities, aggregation characters, and chain packing properties. Polymer DOTFP-PhI with a more twisted backbone showed a lower degree of aggregation in solution but an increased film crystallinity than polymer DOTFP-TPD. An organic thin-film transistor and NF-OSC based on DOTFP-PhI, processed with a nonhalogenated solvent, exhibited a high hole mobility up to 1.20 cm2 V-1 s-1 and a promising power conversion efficiency up to 10.65%, respectively. The results demonstrate that DOTFP is a promising building block for constructing wide bandgap polymers and backbone coplanarity tuning is an effective strategy to develop high-performance organic semiconductors processable with a nonhalogenated solvent.

High-Performance All-Polymer Solar Cells Enabled by an n-Type Polymer Based on a Fluorinated Imide-Functionalized Arene.

A novel imide-functionalized arene, di(fluorothienyl)thienothiophene diimide (f-FBTI2), featuring a fused backbone functionalized with electron-withdrawing F atoms, is designed, and the synthetic challenges associated with highly electron-deficient fluorinated imide are overcome. The incorporation of f-FBTI2 into polymer affords a high-performance n-type semiconductor f-FBTI2-T, which shows a reduced bandgap and lower-lying lowest unoccupied molecular orbital (LUMO) energy level than the polymer analog without F or with F-functionalization on the donor moiety. These optoelectronic properties reflect the distinctive advantages of fluorination of electron-deficient acceptors, yielding "stronger acceptors," which are desirable for n-type polymers. When used as a polymer acceptor in all-polymer solar cells, an excellent power conversion efficiency of 8.1% is achieved without any solvent additive or thermal treatment, which is the highest value reported for all-polymer solar cells except well-studied naphthalene diimide and perylene diimide-based n-type polymers. In addition, the solar cells show an energy loss of 0.53 eV, the smallest value reported to date for all-polymer solar cells with efficiency > 8%. These results demonstrate that fluorination of imide-functionalized arenes offers an effective approach for developing new electron-deficient building blocks with improved optoelectronic properties, and the emergence of f-FBTI2 will change the scenario in terms of developing n-type polymers for high-performance all-polymer solar cells.

Cyano-Substituted Head-to-Head Polythiophenes: Enabling High-Performance n-Type Organic Thin-Film Transistors.

Polythiophenes, built on the electron-rich thiophene unit, typically possess high-lying energy levels of the lowest unoccupied molecular orbitals (LUMOs) and show hole-transporting properties. In this study, we develop a series of n-type polythiophenes, P1-P3, based on head-to-head-linked 3,3'-dialkoxy-4,4'-dicyano-2,2'-bithiophene (BTCNOR) with distinct side chains. The BTCNOR unit shows not only highly planar backbone conformation enabled by the intramolecular noncovalent sulfur-oxygen interaction but also significantly suppressed LUMO level attributed to the cyano-substitution. Hence, all BTCNOR-based polymer semiconductors exhibit low-lying LUMO levels, which are ∼1.0 eV lower than that of regioregular poly(3-hexylthiophene) (rr-P3HT), a benchmark p-type polymer semiconductor. Consequently, all of the three polymers can enable unipolar n-type transport characteristics in organic thin-film transistors (OTFTs) with low off-currents ( Ioffs) of 10-10-10-11 A and large current on/off ratios ( Ion/ Ioffs) at the level of 106. Among them, polymer P2 with a 2-ethylhexyl side chain offers the highest film ordering, leading to the best device performance with an excellent electron mobility (µe) of 0.31 cm2 V-1 s-1 in off-center spin-cast OTFTs. To the best of our knowledge, this is the first report of n-type polythiophenes with electron mobility comparable to the hole mobility of the benchmark p-type rr-P3HT and approaching the electron mobility of the most-studied n-type polymer, poly(naphthalene diimide- alt-bithiophene) (i.e., N2200). The change of charge carrier polarity from p-type (rr-P3HT) to n-type (P2) with comparable mobility demonstrates the obvious effectiveness of our structural modification. Adoption of n-hexadecyl (P1) and 2-butyloctyl (P3) side chains leads to reduced film ordering and results in 1-2 orders of magnitude lower µes, showing the critical role of side chains in optimizing device performance. This study demonstrates the unique structural features of head-to-head linkage containing BTCNOR for constructing high-performance n-type polymers, i.e., the alkoxy chain for backbone conformation locking and providing polymer solubility as well as the strong electron-withdrawing cyano group for lowering LUMO levels and enabling n-type performance. The design strategy of BTCNOR-based polymers provides useful guidelines for developing n-type polythiophenes.

Using the capnogram to assess pulmonary perfusion during a lobectomy: case studies.

Capnography is an effective and non-invasive method for monitoring patients during general anesthesia and can reflect the changes in both the respiratory function as well as the circulatory function. In this paper, we present four cases of lobectomy in which we observed a "chair-like" waveform on performing capnography after the surgery. In all the cases, the appearance of this "chair-like" waveform led to the suspicion of a blockage in the pulmonary artery perfusion, which was then confirmed to be an obstruction in the pulmonary artery on further investigation. This suggests that during lobectomy, capnography can help confirm that the pulmonary circulation is unobstructed. We believe that it is very important to observe the changes of end-tidal carbon dioxide pressure and capnogram during one-lung ventilation, particularly in cases of pulmonary artery anastomosis.

Isomerization enabling near-infrared electron acceptors.

An isomerization method was utilized to yield a novel near-infrared nonfullerene acceptor DTA-IC-M. By simply changing the linking fashion between the anthracene and neighboring thiophenes, a remarkable redshift (∼170 nm) of absorption was observed from DTA-IC-S to its isomer DTA-IC-M which shows a maximum absorption peak over 800 nm with a narrow bandgap of 1.35 eV. Due to the enhanced photo-to-current response in the near-infrared region, an improved short-circuit current of 12.96 mA cm-2 was achieved for the DTA-IC-M based OSCs.

Genetic polymorphism of catechol-O-methyltransferase modulates the association of green tea consumption and lung cancer.

Tea polyphenols are strong antioxidants, which can be rapidly O-methylated by catechol-O-methyltransferase (COMT). Thus, it is possible that the genetic polymorphism of COMT can modulate the association of green tea consumption and lung cancer. Here, we designed a case-control study to evaluate the combined effect of green tea consumption and COMT genotypes on the risk of lung cancer. A total of 237 lung cancer patients and 474 healthy controls were recruited. Questionnaires were administered to obtain demographic data, smoking status, green tea consumption, fruits and vegetables intake, exposure to cooking fumes, and family history of lung cancer. Genotypes for COMT were identified by PCR. Smoking, green tea consumption, exposure to cooking fumes, and family history of lung cancer were associated with the development of lung cancer. When green tea drinkers carrying COMT HL/LL genotypes were selected as the reference group, drinkers carrying the COMT HH genotype had a higher risk for the development of lung cancer (odds ratio: 1.97, 95% confidence interval: 0.99-3.91). Among the current and ever smokers, the elevated risk for lung cancer was more apparent in green tea drinkers carrying the COMT HH genotype compared with green tea drinkers carrying COMT HL/LL genotypes (odds ratio: 5.84, 95% confidence interval: 1.75-19.45). Green tea drinkers with greater activity of the COMT genotype, whereby polyphenols are effectively excluded, will gain fewer protective benefits against lung cancer development.

Quinoxaline-Based Wide Band Gap Polymers for Efficient Nonfullerene Organic Solar Cells with Large Open-Circuit Voltages.

We present here a series of wide-band-gap ( Eg: >1.8 eV) polymer donors by incorporating thiophene-flanked phenylene as an electron-donating unit and quinoxaline as an electron-accepting co-unit to attain large open-circuit voltages ( Vocs) and short-circuit currents ( Jscs) in nonfullerene organic solar cells (OSCs). Fluorination was utilized to fine-tailor the energetics of polymer frontier molecular orbitals (FMOs) by replacing a variable number of H atoms on the phenylene moiety with F. It was found that fluorination can effectively modulate the polymer backbone planarity through intramolecular noncovalent S···F and/or H···F interactions. Polymers (P2-P4) show an improved molecular packing with a favorable face-on orientation compared to their nonfluorinated analogue (P1), which is critical to charge carrier transport and collection. When mixed with IDIC, a nonfullerene acceptor, P3 with two F atoms, achieves a remarkable Voc of 1.00 V and a large Jsc of 15.99 mA/cm2, simultaneously, yielding a power-conversion efficiency (PCE) of 9.7%. Notably, the 1.00 V Voc is among the largest values in the IDIC-based OSCs, leading to a small energy loss ( Eloss: 0.62 eV) while maintaining a large PCE. The P3:IDIC blend shows an efficient exciton dissociation through hole transfer even under a small energy offset of 0.16 eV. Further fluorination leads to the polymer P4 with increased chain-twisting and mismatched FMO levels with IDIC, showing the lowest PCE of 2.93%. The results demonstrate that quinoxaline-based copolymers are promising donors for efficient OSCs and the fluorination needs to be fine-adjusted to optimize the interchain packing and physicochemical properties of polymers. Additionally, the structure-property correlations from this work provide useful insights for developing wide-band-gap polymers with low-lying highest occupied molecular orbitals to minimize Eloss and maximize Voc in nonfullerene OSCs for efficient power conversion.

Aggregation Strength Tuning in Difluorobenzoxadiazole-Based Polymeric Semiconductors for High-Performance Thick-Film Polymer Solar Cells.

High-performance polymer solar cells (PSCs) with thick active layers are essential for large-scale production. Polymer semiconductors exhibiting a temperature-dependent aggregation property offer great advantages toward this purpose. In this study, three difluorobenzoxadiazole (ffBX)-based donor polymers, PffBX-T, PffBX-TT, and PffBX-DTT, were synthesized, which contain thiophene (T), thieno[3,2- b]thiophene (TT), and dithieno[3,2- b:2',3'- d]thiophene (DTT) as the π-spacers, respectively. Temperature-dependent absorption spectra reveal that the aggregation strength increases in the order of PffBX-T, PffBX-TT, and PffBX-DTT as the π-spacer becomes larger. PffBX-TT with the intermediate aggregation strength enables well-controlled disorder-order transition in the casting process of blend film, thus leading to the best film morphology and the highest performance in PSCs. Thick-film PSCs with an average power conversion efficiency (PCE) of 8.91% and the maximum value of 9.10% are achieved using PffBX-TT:PC71BM active layer with a thickness of 250 nm. The neat film of PffBX-TT also shows a high hole mobility of 1.09 cm2 V-1 s-1 in organic thin-film transistors. When PffBX-DTT and PffBX-T are incorporated into PSCs utilizing PC71BM acceptor, the average PCE decreases to 6.54 and 1.33%, respectively. The performance drop mainly comes from reduced short-circuit current, as a result of nonoptimal blend film morphology caused by a less well-controlled film formation process. A similar trend was also observed in nonfullerene type thick-film PSCs using IT-4F as the electron acceptor. These results show the significance of polymer aggregation strength tuning toward optimal bulk heterojunction film morphology using ffBX-based polymer model system. The study demonstrates that adjusting π-spacer is an effective method, in combination with other important approaches such as alkyl chain optimization, to generate high-performance thick-film PSCs which are critical for practical applications.

(Semi)ladder-Type Bithiophene Imide-Based All-Acceptor Semiconductors: Synthesis, Structure-Property Correlations, and Unipolar n-Type Transistor Performance.

Development of high-performance unipolar n-type organic semiconductors still remains as a great challenge. In this work, all-acceptor bithiophene imide-based ladder-type small molecules BTI n and semiladder-type homopolymers PBTI n ( n = 1-5) were synthesized, and their structure-property correlations were studied in depth. It was found that Pd-catalyzed Stille coupling is superior to Ni-mediated Yamamoto coupling to produce polymers with higher molecular weight and improved polymer quality, thus leading to greatly increased electron mobility (µe). Due to their all-acceptor backbone, these polymers all exhibit unipolar n-type transport in organic thin-film transistors, accompanied by low off-currents (10-10-10-9 A), large on/off current ratios (106), and small threshold voltages (∼15-25 V). The highest µe, up to 3.71 cm2 V-1 s-1, is attained from PBTI1 with the shortest monomer unit. As the monomer size is extended, the µe drops by 2 orders to 0.014 cm2 V-1 s-1 for PBTI5. This monotonic decrease of µe was also observed in their homologous BTI n small molecules. This trend of mobility decrease is in good agreement with the evolvement of disordered phases within the film, as revealed by Raman spectroscopy and X-ray diffraction measurements. The extension of the ladder-type building blocks appears to have a large impact on the motion freedom of the building blocks and the polymer chains during film formation, thus negatively affecting film morphology and charge carrier mobility. The result indicates that synthesizing building blocks with more extended ladder-type backbone does not necessarily lead to improved mobilities. This study marks a significant advance in the performance of all-acceptor-type polymers as unipolar electron transporting materials and provides useful guidelines for further development of (semi)ladder-type molecular and polymeric semiconductors for applications in organic electronics.

Polymer semiconductors incorporating head-to-head linked 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole.

Head-to-head linked bithiophenes with planar backbones hold distinctive advantages for constructing organic semiconductors, such as good solubilizing capability, enabling narrow bandgap, and effective tuning of frontier molecular orbital (FMO) levels using minimal thiophene numbers. In order to realize planar backbone, alkoxy chains are typically installed on thiophene head positions, owing to the small van der Waals radius of oxygen atom and accompanying noncovalent S⋯O interaction. However, the strong electron donating alkoxy chains on the electron-rich thiophenes lead to elevated FMO levels, which are detrimental to material stability and device performance. Thus, a new design approach is needed to counterbalance the strong electron donating property of alkoxy chains to bring down the FMOs. In this study, we designed and synthesized a new head-to-head linked building block, 4-alkoxy-5-(3-alkylthiophen-2-yl)thiazole (TRTzOR), using an electron-deficient thiazole to replace the electron-rich thiophene. Compared to previously reported 3-alkoxy-3'-alkyl-2,2'-bithiophene (TRTOR), TRTzOR is a weaker electron donor, which considerably lowers FMOs and maintains planar backbone through the noncovalent S⋯O interaction. The new TRTzOR was copolymerized with benzothiadiazoles with distinct F numbers to yield a series of polymer semiconductors. Compared to TRTOR-based analogous polymers, these TRTzOR-based polymers have broader absorption up to 950 nm with lower-lying FMOs by 0.2-0.3 eV, and blending these polymers with PC71BM leads to polymer solar cells (PSCs) with improved open-circuit voltage (V oc) by ca. 0.1 V and a much smaller energy loss (E loss) as low as 0.59 eV. These results demonstrate that thiazole substitution is an effective approach to tune FMO levels for realizing higher V ocs in PSCs and the small E loss renders TRTzOR a promising building block for developing high-performance organic semiconductors.

2,1,3-Benzothiadiazole-5,6-dicarboxylicimide-Based Polymer Semiconductors for Organic Thin-Film Transistors and Polymer Solar Cells.

A series of polymer semiconductors incorporating 2,1,3-benzothiadiazole-5,6-dicarboxylicimide (BTZI) as strong electron-withdrawing unit and an alkoxy-functionalized head-to-head linkage containing bithiophene or bithiazole as highly electron-rich co-unit are designed and synthesized. Because of the strong intramolecular charge transfer characteristics, all three polymers BTZI-TRTOR (P1), BTZI-BTOR (P2), and BTZI-BTzOR (P3) exhibit narrow bandgaps of 1.13, 1.05, and 0.92 eV, respectively, resulting in a very broad absorption ranging from 350 to 1400 nm. The highly electron-deficient 2,1,3-benzothiadiazole-5,6-dicarboxylicimide and alkoxy-functionalized bithiophene (or thiazole) lead to polymers with low-lying lowest unoccupied molecular orbitals (-3.96 to -4.28 eV) and high-lying highest occupied molecular orbitals (-5.01 to -5.20 eV). Hence, P1 and P3 show substantial and balanced ambipolar transport with electron mobilities/hole mobilities of up to 0.86/0.51 and 0.95/0.50 cm2 V-1 s-1, respectively, and polymer P2 containing the strongest donor unit exhibited unipolar p-type performance with an average hole mobility of 0.40 cm2 V-1 s-1 in top-gate/bottom-contact thin-film transistors with gold as the source and drain electrodes. When incorporated into bulk heterojunction polymer solar cells, the narrow bandgap (1.13 eV) polymer P1 shows an encouraging power conversion efficiency of 4.15% with a relatively large open-circuit voltage of 0.69 V, which corresponds to a remarkably small energy loss of 0.44 eV. The power conversion efficiency of P1 is among the highest reported to date with such a small energy loss in polymer:fullerene solar cells.

Head-to-Head Linkage Containing Bithiophene-Based Polymeric Semiconductors for Highly Efficient Polymer Solar Cells.

Narrow bandgap (1.37-1.46 eV) polymers incorporating a head-to-head linkage containing 3-alkoxy-3'-alkyl-2,2'-bithiophene are synthesized. The head-to-head linkage enables polymers with sufficient solubility and the noncovalent sulfur-oxygen interaction affords polymers with high degree of backbone planarity and film ordering. When integrated into polymer solar cells, the polymers show a promising power conversion efficiency approaching 10%.

Modified Leukocyte Filter Removes Tumor Cells from the Salvaged Blood.

BACKGROUND: Intraoperative blood salvage, an effective blood conservation strategy, has not been applied in onco-surgery, because of potential malignant cell contamination. In this study we tested effectiveness of a modified leukocyte depletion filter (M-LDF) for removal of tumor cells. MATERIALS AND METHODS: The effects of M-LDF and regular LDF on removal of cells (HepG2 cell line) were compared. The safety of M-LDF was tested with blood (collected and washed during onco-surgery), the salvaged blood mixed with tumor cells from the solid tumor of the same patient, or mixed with HepG2 cells (n=30 in each protocol). Cancer cells were identified by flow cytometry, culture and bioassay with and without filtration. RESULTS: M-LDF removed 5-log of HepG2 and nucleated cells, which was much higher than regular LDF, and cells were destroyed when they passed through M-LDF. Cytokeratin-positive cells in all samples were removed by M-LDF. Invasive growth adherent cells were found in most of unfiltered samples and 67% of the inoculated nude mice developed tumors in LDF-treated sample. Neither adherent cells nor nude mice developed tumors were found in M-LDF-treated samples. DISCUSSION AND CONCLUSION: Since M-LDF can effectively remove and destroy cancer cells in the salvaged blood, it has great potential for clinical application.