Browsing by Issue Date, starting with "2019-07-28"

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Infrared spectrum of hydrogenated corannulene rim-HC20H10 isolated in solid para-hydrogen
(2019-07-28)
Sundararajan, Pavithraa
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Tsuge, Masashi
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Baba, Masaaki
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Sakurai, Hidehiro
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Lee, Yuan-Pern
Hydrogenated polycyclic aromatic hydrocarbons have been proposed to be carriers of the interstellar unidentified infrared (UIR) emission bands and the catalysts for formation of H-2; spectral characterizations of these species are hence important. We report the infrared (IR) spectrum of mono-hydrogenated corannulene (HC20H10) in solid para-hydrogen (p-H-2). In experiments of electron bombardment of a mixture of corannulene and p-H-2 during deposition of a matrix at 3.2 K, two groups of spectral lines increased with time during maintenance of the matrix in darkness after deposition. Lines in one group were assigned to the most stable isomer of hydrogenated corannulene, rim-HC20H10, according to the expected chemistry and a comparison with scaled harmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. The lines in the other group do not agree with predicted spectra of other HC20H10 isomers and remain unassigned. Alternative hydrogenation was achieved with H atoms produced photochemically in the infrared-induced reaction Cl + H-2 (v = 1) -> H + HCl in a Cl-2/C20H10/p-H-2 matrix. With this method, only lines attributable to rim-HC20H10 were observed, indicating that hydrogenation via a quantum-mechanical tunneling mechanism produces preferably the least-energy rim-HC20H10 regardless of similar barrier heights and widths for the formation of rim-HC20H10 and hub-HC20H10. The mechanisms of formation in both experiments are discussed. The bands near 3.3 and 3.4 mu m of rim-HC20H10 agree with the UIR emission bands in position and relative intensity, but other bands do not match satisfactorily with the UIR bands.
Enterotype-based Analysis of Gut Microbiota along the Conventional Adenoma-Carcinoma Colorectal Cancer Pathway
(2019-07-29)
Yang, Tzu-Wei
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Lee, Wei-Hsiang
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Tu, Siang-Jyun
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Huang, Wei-Chih
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Chen, Hui-Mei
The dysbiosis of human gut microbiota is strongly associated with the development of colorectal cancer (CRC). The dysbiotic features of the transition from advanced polyp to early-stage CRC are largely unknown. We performed a 16S rRNA gene sequencing and enterotype-based gut microbiota analysis study. In addition to Bacteroides-and Prevotella-dominated enterotypes, we identified an Escherichia-dominated enterotype. We found that the dysbiotic features of CRC were dissimilar in overall samples and especially Escherichia-dominated enterotype. Besides a higher abundance of Fusobacterium, Enterococcus, and Aeromonas in all CRC faecal microbiota, we found that the most notable characteristic of CRC faecal microbiota was a decreased abundance of potential beneficial butyrate-producing bacteria. Notably, Oscillospira was depleted in the transition from advanced adenoma to stage 0 CRC, whereas Haemophilus was depleted in the transition from stage 0 to early-stage CRC. We further identified 7 different CAGs by analysing bacterial clusters. The abundance of microbiota in cluster 3 significantly increased in the CRC group, whereas that of cluster 5 decreased. The abundance of both cluster 5 and cluster 7 decreased in the Escherichia-dominated enterotype of the CRC group. We present the first enterotype-based faecal microbiota analysis. The gut microbiota of colorectal neoplasms can be influenced by its enterotype.
The influence of dilute aluminum and molybdenum on stacking fault and twin formation in FeNiCoCr-based high entropy alloys based on density functional theory
(2019-07-29)
Yu, Peijun
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Zhuang, Yu
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Chou, Jyh-Pin
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Wei, Jie
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Lo, Yu-Chieh
Stacking faults, as defects of disordered crystallographic planes, are one of the most important slipping mechanisms in the commonly seen lattice, face-centered cubic (FCC). Such defects can initiate twinning which strengthens mechanical properties, e.g. twinning-induced plasticity (TWIP), of high entropy alloys (HEAs) at cryogenic temperatures. In this work, by using density functional theory (DFT), the twinning initiated from stacking faults is discussed with regard to two different solute elements, Al and Mo, in the FeNiCoCr HEAs. Our results show that adding aluminum (Al) has noticeable enhancement of twinnability while molybdenum (Mo) only induces more stacking faults in the FeNiCoCr-based HEAs.
Neutralized chimeric DNA probe for the improvement of GC-rich RNA detection specificity on the nanowire field-effect transistor
(2019-07-30)
Chou, Wei-Cheng
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Hu, Wen-Pin
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Yang, Yuh-Shyong
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Chan, Hardy Wai-Hong
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Chen, Wen-Yih
Silicon nanowire (SiNW) field-effect transistors (FETs) is a powerful tool in genetic molecule analysis because of their high sensitivity, short detection time, and label-free detection. In nucleic acid detection, GC-rich nucleic acid sequences form self-and cross-dimers and stem-loop structures, which can easily obtain data containing signals from nonspecific DNA binding. The features of GC-rich nucleic acid sequences cause inaccuracies in nucleic acid detection and hinder the development of precision medicine. To improve the inaccurate detection results, we used phosphate-methylated (neutral) nucleotides to synthesize the neutralized chimeric DNA oligomer probe. The probe fragment originated from a primer for the detection of hepatitis C virus (HCV) genotype 3b, and single-mismatched and perfect-matched targets were designed for single nucleotide polymorphisms (SNP) detection on the SiNW FET device. Experimental results revealed that the HCV-3b chimeric neutralized DNA (nDNA) probe exhibited better performance for SNP discrimination in 10 mM bis-tris propane buffer at 25 degrees C than a regular DNA probe. The SNP discrimination of the nDNA probe could be further improved at 40 degrees C on the FET device. Consequently, the neutralized chimeric DNA probe could successfully distinguish SNP in the detection of GC-rich target sequences under optimal operating conditions on the SiNW FET device.
Vicinal difunctionalization of alkenes by four-component radical cascade reaction of xanthogenates, alkenes, CO, and sulfonyl oxime ethers
(2019-07-31)
Sumino, Shuhei
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Fukuyama, Takahide
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Sasano, Mika
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Ryu, Ilhyong
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Jacquet, Antoine
Four-component coupling reactions between xanthogenates, alkenes, CO, and sulfonyl oxime ethers were studied. In the presence of hexabutylditin, working as a propagating radical reagent, the chain reaction proceeds, as expected, taking into account reagents polarities, affording the corresponding functionalized alpha-keto oximes. Although yields are modest, this rare one-pot four-component process is easy to carry out and the resulting compounds, bearing multiple functionalities, have the potential for further elaboration.
機械設計學用鏈結強化教學策略促進學習動機與成效
(2019-07-31)
楊秉祥
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國立交通大學機械工程學系
Favorable gallbladder cancer mortality-to-incidence ratios of countries with good ranking of world's health system and high expenditures on health
(2019-07-31)
Wang, Chi-Chih
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Tsai, Ming-Chang
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Wang, Shao-Chuan
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Peng, Cheng-Ming
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Lee, Hsiang-Lin
BackgroundThe mortality-to-incidence ratio (MIR) is a marker that reflects the clinical outcome of cancer treatment. MIR as a prognostic marker is more accessible when compared with long-term follow-up survival surveys. Theoretically, countries with good health care systems would have favorable outcomes for cancer; however, no report has yet demonstrated an association between gallbladder cancer MIR and the World's Health System ranking.MethodsWe used linear regression to analyze the correlation of MIRs with the World Health Organization (WHO) rankings and total expenditures on health/gross domestic product (e/GDP) in 57 countries selected according to the data quality.ResultsThe results showed high crude rates of incidence/mortality but low MIR in more developed regions. Among continents, Europe had the highest crude rates of incidence/mortality, whereas the highest age-standardized rates (ASR) of incidence/mortality were in Asia. The MIR was lowest in North America and highest in Africa (0.40 and 1.00, respectively). Furthermore, favorable MIRs were correlated with good WHO rankings and high e/GDP (p=0.01 and p=0.030, respectively).ConclusionsThe MIR variation for gallbladder cancer is therefore associated with the ranking of the health system and the expenditure on health.
A model study on the mechanism and kinetics for the dissociation of water anion
(2019-08-01)
Trinh Le Huyen
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Long Van Duong
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Minh Tho Nguyen
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Ming Chang Lin
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交大名義發表
Quantum chemical computations using both density functional theory (B3LYP functional) and wavefunction (MP2 and CCSD(T)) methods, with the 6-311++G(3df,2p) and aug-cc-pVnZ (n = D,T,Q) basis sets, in conjunction with a polarizable continuum model (PCM) method for treating structures in solution, were carried out to look again at a series of small negatively charged water species [(H2O)(n)](center dot-). For each size n of [(H2O)(n)](center dot-) in aqueous solution with n = 2, 3, and 4, two distinct structural motifs can be identified: a classical water radical anion formed by hydrogen bonds and a molecular pincer in which the excess electron is directly interacting with H atoms. In aqueous solution, both motifs have comparable energy content and likely coexist and compete for the ground state. Some water anion isomers can dissociate when interaction with a water molecule, [(H2O)(n)](center dot-) + H2O -> H-center dot(H2O)(m) + OH-(H2O)(n)(-)(m), through successive hydrogen transfers with moderate energy barriers. This reaction can also be regarded as a water-splitting process in which the H transfers involved take place mainly within a water trimer, whereas other water molecules tend to stabilize transition structures through microsolvation rather than direct participation. Calculated absolute rate constants for the reversed reaction H-center dot(H2O)(2) + OH-(H2O)(2) -> [(H2O)(4)](center dot) + H2O with both H and D isotopes agree well with the experimentally evaluated counterpart and lend a kinetic support for the involvement of a tetramer unit.
Landslide monitoring with interferometric SAR in Liugui, a vegetated area
(2019-08-01)
Shih, Peter Tian-Yuan
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Wang, Huijung
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Li, Kuo-Wei
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Liao, Jyh-Jong
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Pan, Yii-Wen
Interferometric SAR analysis with a time series of images obtained from satellite has been proven to be a useful monitoring scheme for geomorphological changes, particularly related to the vertical dimension. The success of this technique relies on the coherence between the images. This imposes severe challenges for applications in vegetated areas. In this study, the landslide process of a site located in Liugui, southern Taiwan, is investigated by a time series of SAR images collected from ALOS PALSAR and Sentinel 1A. This landslide monitoring site is heavily vegetated. From the Persistent Scattering (PS) analysis, ALOS PALSAR presented more extracted points. The wavelength of the band may be a decisive factor. The time series of ALOS images spans across the deadliest typhoon impacted Taiwan in recorded history, Typhoon Morakot on 8 August 2009. It is clear that there are more PS points extracted from the time series after the event as compared to before Typhoon Morakot. This is largely explained by the increase in the amount of bare earth after the disaster. From the interferometric SAR analysis, the development of headward erosion could be observed. Although the number of PS points is limited, the understanding of erosion and landslide progress in the area could still be improved while integrating with the digital elevation model collected with airborne lidar, historic aerial photos, and images collected with UAS (Unmanned Aviation Systems). Together with the in situ measurements, the colluvium depth ranges from 2 - 40 m in the area. The surface instability is expected to persist.
Plasmonic Nanolasers Enhanced by Hybrid Graphene-Insulator-Metal Structures
(2019-08-01)
Li, Heng
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Li, Jhu-Hong
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Hong, Kuo-Bin
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Yu, Min-Wen
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Chun, Yi-Cheng
Graphene is a two-dimensional (2D) structure that creates a linear relationship between energy and momentum that not only forms massless Dirac fermions with extremely high group velocity but also exhibits a broadband transmission from 300 to 2500 nm that can be applied to many optoelectronic applications, such as solar cells, light-emitting devices, touchscreens, ultrafast photodetectors, and lasers. Although the plasmonic resonance of graphene occurs in the terahertz band, graphene can be combined with a noble metal to provide a versatile platform for supporting surface plasmon waves. In this study, we propose a hybrid graphene-insulator-metal (GIM) structure that can modulate the surface plasmon polariton (SPP) dispersion characteristics and thus influence the performance of plasmonic nanolasers. Compared with values obtained when graphene is not used on an Al template, the propagation length of SPP waves can be increased 2-fold, and the threshold of nanolasers is reduced by 50% when graphene is incorporated on the template. The GIM structure can be further applied in the future to realize electrical control or electrical injection of plasmonic devices through graphene.
Establishment of a large-diameter pipeline failure risk matrix in water distribution systems in Taiwan
(2019-08-01)
Huang, Kochin
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Chuo, Paul
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Lin, Kim-loong
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Yu, Mengsyu
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Huang, Chihpin
The bursting of large-diameter water pipelines in distribution systems will lead to industrial, economic, and public safety impacts. Therefore, multi-criteria analysis (MCA) was applied in this study, which utilizes a series of quantifiable parameters to establish the mathematical method of a risk model. The risk matrix of a pipeline was defined as the multiple of the probability of pipeline failure and potential consequences of pipeline failure. By combining the GIS (geographic information system), each evaluation unit was assigned to different risk levels. The large-diameter (above 800 mm) pipeline length statistic for various risk evaluation units of Taiwan Water Corporation reveals the length of high risk is 171 km (7.7%), secondary high risk 574.6 km (25.8%), middle risk 714.3 km (32%), low risk 701.5 km (31.5%), and the unranked length is 67.8 km (3.0%). Finally, the detection frequencies were classified as high risk with a term check of every five years, sub-high risk with planned check every five to ten years, medium risk with checking/monitoring if needed, and low risk with quick repair and no need to take measurements and monitoring. Therefore, we can significantly lower the probability of bursting for large-diameter pipelines in the water distribution system.
Mediation analysis for new recognition criteria, working hours and overwork-related disease: a nationwide ecological study using 11-year follow-up data in Taiwan
(2019-08-01)
Lin, Sheng-Hsuan
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Chou, Meng-Ying
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Lin, Ro-Ting
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統計學研究所
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Institute of Statistics
Objectives Taiwan revised its criteria for overwork-related cerebrovascular and cardiovascular disease (CCVD) in 2010. A new definition of overwork increased the number of recognised cases. Meanwhile, actual average working hours decreased. We estimated the effects of the revised criteria on the number of overwork-related CCVD cases and the mediation effect through reduced working hours. Methods From the Labor Insurance of Taiwan, we collected data on the total number of overwork-related CCVD cases from 2006 to 2016 and average monthly working hours for 13 industry groups. We conducted causal mediation analysis to investigate the mechanism of the effect of new criteria on CCVD mediated by working hours. Results From 2006 to 2016, 594 overwork-related cases of CCVD were recognised across 13 industry groups. After introducing the new criteria, overwork-related CCVD increased by 8.40 cases (per one million person-years) (95% CI 4.53 to 15.05), which resulted from a decrease of 1.54 (95% CI 0.22 to 3.82) cases due to reduced working hours (mediation effect) and an increase of 9.93 (95% CI 5.24 to 18.17) cases related to the effect of the criteria change and other covariates excluding working hours (alternative effect). Conclusions Working hours are an important mediator of the effect of policy on the rate of overwork-related CCVD. Introducing new criteria for recognising overwork-related disease might raise awareness and prompt reductions in working hours, which also help to reduce CCVD. Our findings suggest that understanding mediation effects is important to evaluating national health policies.
A comparison of multiple Rosetta data sets and 3D model calculations of 67P/Churyumov-Gerasimenko coma around equinox (May 2015)
(2019-08-01)
Marschall, R.
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Rezac, L.
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Kappel, D.
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Su, C. C.
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Gerig, S. -B.
We have used the latest available shape model for gas and dust simulations of the inner coma of comet 67P/Churyumov-Gerasimenko for the period around May 2015 (equinox). We compare results from a purely insolation-driven model with a complementary set of observations made by ROSINA, VIRTIS, MIRO, and OSIRIS within the same period. The observations include - for the first time - inverted MIRO measurements of gas density, temperature and bulk velocity to constrain the model. The comparisons show that, as in November 2014 (Marschall et al., 2016), insolation-driven activity does not provide an adequate fit to the data. Both VIRTIS and MIRO observations indicate that emissions from the Hatmehit and Imhotep regions of the nucleus are strongly depleted in total gas, H2O, and dust emissions in this case. The MIRO inversion provides a challenging constraint to the models as a consequence of the terminator orbit and nucleus pointing of the spacecraft. Nonetheless a consistent picture with a dominance of outgassing from the Hapi region, even at equinox, is clearly evident. An inhomogeneous model consistent with models proposed for the November 2014 time-frame was constructed and provides a better fit to the data. As far as we are aware this is the first time comae data from four Rosetta instruments have been used to constrain within one self-contained model the emission distribution at the nucleus surface and study the dynamics of the gas and dust outflow.
An advanced IoT system for assisting ubiquitous manufacturing with 3D printing
(2019-08-01)
Chen, Toly
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Wang, Yu-Cheng
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工業工程與管理學系
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Department of Industrial Engineering and Management
An advanced Internet-of-things (IoT) system for assisting ubiquitous manufacturing with three-dimensional (3D) printing was designed. The system receives orders from customers on the move online and then distributes the required pieces to nearby 3D printing facilities. After the printing is completed, a freight truck visits the printing facilities sequentially to collect the printed pieces. To minimize the cycle time for delivering the order, an optimization approach that combines workload balancing and finding the shortest delivery path was proposed in this study. However, the optimization problem remained difficult; to solve this, an algorithm was developed. The effectiveness of the proposed methodology was assessed through an experiment conducted in Taichung City, Taiwan. According to the experimental results, the proposed methodology outperforms two existing methods by reducing the cycle times by an average of 33%. It also successfully balances the workloads of the 3D printing facilities, incentivizing these facilities to join the system.
Space-Time Evolution of Greenland Ice Sheet Elevation and Mass From Envisat and GRACE Data
(2019-08-01)
Yang, Yuande
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Li, Fei
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Hwang, Cheinway
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Ding, Minghu
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Ran, Jiangjun
Precise measurements of height changes (HCs) are important for improved estimates of mass balance of the Greenland Ice Sheet (GrIS). Here we determine 10 years of precise, high-resolution HCs of the GrIS from Envisat radar altimeter using a subwaveform retracker and a modified repeat-track method. The HCs show clear seasonal changes and monotonic declines over glaciers on the coasts such as Zachariae IsstrOm. We enhance mass change estimates from Gravity Recovery and Climate Experiment (GRACE) data using HCs and densities from interannual correlations between GRACE-derived mass changes and HCs. We estimate the mass changes of eight drainage basins with our combined mass change. The largest mass change between 2002 and 2012 occurred in the northwest basin and the smallest in the northeast basin. We separate the ice and snow HC rates to derive a ratio (f) between them to characterize the relative importance of ice or snow to mass change. The snow HC rates are mostly positive over the GrIS, except on the margins of the west coast and Zachariae IsstrOm. The mean ice HC rate is -6.6 3.9 cm/year over 2002-2006, which accelerated to -13.9 2.4 cm/year over 2007-2012. The f factors show a clear post-2006 ice dominance in the GrIS mass loss, particularly on the west coast, with a mean 91.4% ice contribution over 2002-2006, increasing to 94.5% over 2007-2012. This indicates increasing mass loss after 2006. A coincident radar altimeter and gravimetry mission is important for studying mass balance and separating snow and ice contributions over space and time.
A Quantitative Analysis of Animation Deformity in Prosthetic Breast Reconstruction
(2019-08-01)
Kim, John Y. S.
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Qiu, Cecil S.
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Chiu, Wen-Kuan
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Feld, Lauren N.
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Mioton, Lauren M.
Background: Animation deformity is characterized by implant deformity with pectoralis contraction after subpectoral implant-based breast reconstruction. Extant methods to measure and analyze animation deformity are hampered by the paucity of objective, quantitative data. The authors endeavored to supplement subjective measures with an in-depth quantitative analysis. Methods: Patients undergoing subpectoral implant-based breast reconstruction were followed prospectively with video analysis of animation deformity. Nipple displacement and surface area of contour deformity in resting and contracted states were quantified using imaging software. Degree of animation was compared to breast size, body mass index, division of pectoralis muscle, complications, and radiation therapy. Results: One hundred forty-five reconstructed breasts (88 patients) were analyzed. Mean nipple displacement was 2.12 +/- 1.04 cm, mean vector of nipple displacement was 62.5 +/- 20.6 degrees, and mean area of skin contour irregularity was 16.4 +/- 15.41 percent. Intraoperative pectoralis division, smooth/ round implants, and bilateral reconstructions were associated with greater deformity. A three-tiered grading system based on thresholds of 2-cm net nipple displacement and 25 percent skin contour irregularity placed 41.4 percent of breasts in grade 1, 35.9 percent in grade 2, and 22.8 percent in grade 3. Interrater variability testing demonstrated 89.5 percent overall agreement (kappa = 0.84). Conclusions: This study presents the first quantitative analysis of animation deformity in prosthetic breast reconstruction. Geometric analysis of nipple displacement vector and increasing animation with pectoralis division both implicate the inferior pectoralis myotome as a primary driver of animation deformity. A concomitant grading schema was developed to provide a standardized framework for discussing animation from patient to patient and from study to study.
Efficient Hot-Electron Transfer under Modal Strong Coupling Conditions with Sacrificial Electron Donors
(2019-08-01)
Cao, Yanfeng
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Oshikiri, Tomoya
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Shi, Xu
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Ueno, Kosei
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Li, Jie
The Front Cover of this special issue illustrates an investigation into hot-electron transfer efficiency under the modal strong coupling conditions. Photocurrent generation on the plasmonic photoanode was monitored with a sacrificial electron donor that consumes hot-holes efficiently. The average internal quantum efficiency at wavelengths from 500 to 800 nm reached 3%. It is emphasized, furthermore, that the Fermi level shift was observed during the hot-electron transfer involving water oxidation by the in-situ spectroelectrochemical measurements at the first time, and successfully resolve the Fermi level shift by the addition of the sacrificial electron donor. More information can be found in the Full Paper by Hiroaki Misawa et al.
Enhanced drug internalization and therapeutic efficacy of PEGylated nanoparticles by one-step formulation with anti-mPEG bispecific antibody in intrinsic drug-resistant breast cancer
(2019-08-01)
Cheng, Yi-An
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Chen, I-Ju
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Su, Yu-Cheng
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Cheng, Kai-Wen
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Lu, Yun-Chi
For those patients with HER2-overexpressing breast cancer, treatment with PEGylated liposomal doxorubicin (PLD) is inefficacious due to the intrinsic low sensitivity to doxorubicin. A very large increase in drug accumulation by active targeting may enhance the therapeutic efficacy of PLD. We established a humanized bispecific antibody (BsAb; mPEG x HER2) which has dual specificity for methoxy-polyethylene glycol (mPEG) and human epidermal growth factor receptor 2 (HER2) to enhance the specificity, internalization and anticancer activity of PLD for cancer cells that overexpress HER2. One-step formulation of PLD with mPEG x HER2 converted the PLD into HER2 targeted liposomes that were stable at 4 degrees C in PBS as well as at 37 degrees C in the presence of serum. alpha HER2/PLD induced receptor-mediated endocytosis and enhanced doxorubicin accumulation in MCF7/HER2 (HER2-amplified) breast cancer cells. alpha HER2/PLD also displayed more than 200-fold increased cytotoxicity to MCF7/HER2 cells and 28-fold increased cytotoxicity to drug-resistant MDA-MB-361 cells with a physical deletion of the TOP2A gene. alpha HER2/PLD specifically accumulated doxorubicin in the nucleus of cancer cells in tumor-bearing mice and produced significantly greater antitumor activity against MCF7/HER2 (P < 0.0001) and MDA-MB-361 (P < 0.05) tumors as compared to untargeted PLD. Furthermore, the cardiotoxicity of alpha HER2/PLD was similar to that of PLD in human cardiomyocytes and in mice. Our results indicate that the one-step formulation of PLD by mPEG x HER2 is a simple method to confer tumor specificity, increase drug internalization and enhance the anticancer activity of PLD against HER2-overexpressing and doxorubicin-resistant breast cancer.
Setting the digital stage: Defining game streaming as an entertainment experience
(2019-08-01)
Lin, Jih-Hsuan Tammy
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Bowman, Nicholas
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Lin, Shu-Fang
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Chen, Yen-Shen
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交大名義發表
Game streaming-viewing live or recorded broadcasts of others' video game play-has become widely popular in recent years due to the emergence of platforms such as Twitch and YouTube Gaming. We position game streaming as a form of collaborative game play, with implications for how we study games and communication. We first review the social history of gaming before explicating game streaming as a gaming activity that involves public performance and varying levels of social interaction and synchrony. The influence of these three core elements on the uses, processes, and effects of game streaming as an entertainment activity are discussed through the twin perspectives of communication and media psychology.
Enhancing performance of ternary blend photovoltaics by tuning the side chains of two-dimensional conjugated polymer
(2019-08-01)
Chen, Chung-Hao
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Lu, Yi-Ju
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Su, Yu-Wei
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Lin, Yu-Che
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Lin, Hsi-Kuei
We prepared the ternary blends active layer by incorporating a new two-dimensional donor-acceptor (D/A) conjugated polymer (BDTTBO) comprising benzo-dithiophene-thiophene-thiophene-benzo oxadiazole chemical units that has three different conjugated side chains bithiophene (BT), benzothiophene (BzT) and thienothiophene (TT) BDTTBO-BT, BDTTBO-BzT and BDTTBO-TT into poly (benzodithiophene-fluorothienothiophene) (PTB7-TH) and PC71BM as for organic photovoltaics (OPVs). We expected that incorporating these BDTTBO with different side chains into the blend of PTB7-TH and PC71BM not only can broaden the absorption of solar spectrum thereby increasing short-circuit current density but also tune the packing of PTB7-TH and the dispersion of PC71BM. In particular, we found that incorporating 10% of BDTTBO-BT to form the PTB7-TH:BDTTBO-BT:PC71BM ternary blend (active layer) device could improve the power conversion efficiency to 10.4% from 9.0% for the binary blend of PTB7-TH:PC71BM device-a relative increase of 15%. We examined the packing orientations of the PBDTTBO:PTB7-TH:PC71BM ternary blend films using synchrotron two-dimensional grazing-incidence wide-angle X-ray scattering, and found that the incorporation of 10% relatively higher crystallinity PBDTTBO-BT, PBDTTBO-BzT or PBDTTBO-TT not only altered the packing orientation of PTB7-TH substantially but also reduced PC71BM cluster size in the ternary blend system, as compared to that in the case of PTB7-TH with PC71BM binary blend, thereby providing more pathways for electrons and thus enhancing the carrier transport in the ternary blend, as evidenced by the carrier mobility.