28 research outputs found

    Graphene Oxide-Based Carbon Interconnecting Layer for Polymer Tandem Solar Cells

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    Tandem polymer solar cells (PSCs), consisting of more than one (normally two) subcells connected by a charge recombination layer (i.e., interconnecting layer), hold great promise for enhancing the performance of PSCs. For an ideal tandem solar cell, the open circuit voltage (<i>V</i><sub>oc</sub>) equals to the sum of those of the subcells while keeping the short circuit current the same as the lower one, leading to an increased overall power conversion efficiency. The interconnecting layer plays an important role in regulating the tandem device performance. Here, we report that graphene oxide (GO)/GO-Cs (cesium neutralized GO) bilayer modified with ultrathin Al and MoO<sub>3</sub> can act as an efficient interconnecting layer in tandem PSCs to achieve a significantly increased <i>V</i><sub>oc</sub>, reaching almost 100% of the sum of the subcell <i>V</i><sub>oc</sub>s under standard AM 1.5 conditions

    Auger Electron Spectroscopy Analysis of the Thermally Induced Degradation of MAPbI<sub>3</sub> Perovskite Films

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    Organometal halide perovskites are highly promising materials for photovoltaic applications due to the rapid growth of power conversion efficiency in recent years. However, thermal stability is still a major hurdle for perovskite solar cells toward commercialization. Herein, we first explore the slow thermal response of the CH3NH3PbI3 perovskite crystal investigated via Auger electron spectroscopy (AES). AES image mapping directly observes the evolution of morphology and elemental distribution over time. The AES small spot analysis demonstrates the precise initial degradation position of perovskite with both information regarding physical changes in crystals and chemical changes in elemental bonding at the nanometer scale. X-ray photoelectron spectroscopy (XPS) was used to confirm the surface chemical bonding and composition of the perovskite crystals. This work provides the first insights into the physical and chemical changes of perovskites investigated by AES upon long-term exposure to heat under ambient conditions

    Photolysis of Chlorine Dioxide under UVA Irradiation: Radical Formation, Application in Treating Micropollutants, Formation of Disinfection Byproducts, and Toxicity under Scenarios Relevant to Potable Reuse and Drinking Water

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    Conversion of potable reuse water utilities and drinking water utilities from a low-pressure UV/H2O2 (LPUV/H2O2) advanced oxidation process (AOP) to alternative AOPs in which oxidants can effectively absorb photons and rapidly generate radicals has attracted great interest. Herein, we propose a novel UVA/ClO2 AOP for different water treatment scenarios because of reduced photon absorption by the background matrix and high molar absorptivity for ClO2 at UVA wavelengths. While the photolysis of ClO2 produces •Cl + O2 or •ClO + O­(3P) via distinct product channels, we determined the parameters needed to accurately model the loss of oxidants and the formation of byproducts and combined a kinetic model with experimental data to determine quantum yields (Φ). Modeling incorporating the optimized Φ simultaneously predicted oxidant loss and the formation of major products −HOCl, Cl–, and ClO3–. We also systematically investigated the removal of three contaminants exhibiting different radical reactivities, the formation of 35 regulated and unregulated halogenated disinfection byproducts (DBPs), DBP-associated toxicity, and N-acetylcysteine thiol reactivity in synthetic or authentic RO permeates/surface waters treated by different AOPs. The kinetic model developed in this study was used to optimize operating conditions to control undesired products and improve contaminant removal efficiency. The results indicate that UVA/ClO2 can outperform LPUV/H2O2 in terms of electrical energy per order of contaminant degradation, disinfection byproduct formation, and toxicity indices

    Imaging the Long Transport Lengths of Photo-generated Carriers in Oriented Perovskite Films

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    Organometal halide perovskite has emerged as a promising material for solar cells and optoelectronics. Although the long diffusion length of photogenerated carriers is believed to be a critical factor responsible for the material’s high efficiency in solar cells, a direct study of carrier transport over long distances in organometal halide perovskites is still lacking. We fabricated highly oriented crystalline CH3NH3PbI3 (MAPbI3) thin-film lateral transport devices with long channel length (∼120 μm). By performing spatially scanned photocurrent imaging measurements with local illumination, we directly show that the perovskite films prepared here have very long transport lengths for photogenerated carriers, with a minority carrier (electron) diffusion length on the order of 10 μm. Our approach of applying scanning photocurrent microscopy to organometal halide perovskites may be further used to elucidate the carrier transport processes and the vastly different carrier diffusion lengths (∼100 nm to 100 μm) in different types of organometal halide perovskites

    Table4_The association between mortality and use of Chinese herbal medicine among incident stage IV esophageal cancer patients: A retrospective cohort study with core herbs exploration.XLSX

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    Esophageal cancer (EC) remains a leading cause of death worldwide and in Taiwan. The prognosis of advanced-stage EC is notably poor, and the treatment options are limited. Chinese herbal medicine (CHM) has been widely used as a complementary treatment for cancer, yet the long-term effect of CHM in stage IV EC remains unclear.The multi-institutional cohort obtained from the Chang Gung research database (CGRD) was used to study the long-term outcome of CHM use among incident stage IV EC patients from 1 January 2002, to 31 December 2018. All patients were followed up to 5 years or the occurrence of death. The overall survival (OS) and disease-specific survival rates were conducted using Kaplan-Meier estimation. Overlap weighing and landmark analysis were used to eliminate confounding and immortal time biases. Furthermore, we demonstrated the core CHMs for stage IV EC by using the Chinese herbal medicine network (CMN) analysis on prescriptions.Nine hundred eighty-five stage IV EC patients were analyzed, including 74 CHM users and 911 non-CHM users. We found the use of CHM was associated with a higher 5-year overall survival rate than CHM nonusers (the cumulative probability: 19.52% versus 6.04%, log-rank test: p The use of CHM seems safe and possibly beneficial among stage IV EC patients with a higher 5-year OS. Further clinical trials on CHM were guaranteed to explore the role of CHM in managing stage IV EC patients.</p

    Table1_The association between mortality and use of Chinese herbal medicine among incident stage IV esophageal cancer patients: A retrospective cohort study with core herbs exploration.DOCX

    No full text
    Esophageal cancer (EC) remains a leading cause of death worldwide and in Taiwan. The prognosis of advanced-stage EC is notably poor, and the treatment options are limited. Chinese herbal medicine (CHM) has been widely used as a complementary treatment for cancer, yet the long-term effect of CHM in stage IV EC remains unclear.The multi-institutional cohort obtained from the Chang Gung research database (CGRD) was used to study the long-term outcome of CHM use among incident stage IV EC patients from 1 January 2002, to 31 December 2018. All patients were followed up to 5 years or the occurrence of death. The overall survival (OS) and disease-specific survival rates were conducted using Kaplan-Meier estimation. Overlap weighing and landmark analysis were used to eliminate confounding and immortal time biases. Furthermore, we demonstrated the core CHMs for stage IV EC by using the Chinese herbal medicine network (CMN) analysis on prescriptions.Nine hundred eighty-five stage IV EC patients were analyzed, including 74 CHM users and 911 non-CHM users. We found the use of CHM was associated with a higher 5-year overall survival rate than CHM nonusers (the cumulative probability: 19.52% versus 6.04%, log-rank test: p The use of CHM seems safe and possibly beneficial among stage IV EC patients with a higher 5-year OS. Further clinical trials on CHM were guaranteed to explore the role of CHM in managing stage IV EC patients.</p

    Table2_The association between mortality and use of Chinese herbal medicine among incident stage IV esophageal cancer patients: A retrospective cohort study with core herbs exploration.XLSX

    No full text
    Esophageal cancer (EC) remains a leading cause of death worldwide and in Taiwan. The prognosis of advanced-stage EC is notably poor, and the treatment options are limited. Chinese herbal medicine (CHM) has been widely used as a complementary treatment for cancer, yet the long-term effect of CHM in stage IV EC remains unclear.The multi-institutional cohort obtained from the Chang Gung research database (CGRD) was used to study the long-term outcome of CHM use among incident stage IV EC patients from 1 January 2002, to 31 December 2018. All patients were followed up to 5 years or the occurrence of death. The overall survival (OS) and disease-specific survival rates were conducted using Kaplan-Meier estimation. Overlap weighing and landmark analysis were used to eliminate confounding and immortal time biases. Furthermore, we demonstrated the core CHMs for stage IV EC by using the Chinese herbal medicine network (CMN) analysis on prescriptions.Nine hundred eighty-five stage IV EC patients were analyzed, including 74 CHM users and 911 non-CHM users. We found the use of CHM was associated with a higher 5-year overall survival rate than CHM nonusers (the cumulative probability: 19.52% versus 6.04%, log-rank test: p The use of CHM seems safe and possibly beneficial among stage IV EC patients with a higher 5-year OS. Further clinical trials on CHM were guaranteed to explore the role of CHM in managing stage IV EC patients.</p

    X-ray Photoelectron Spectrometry Depth Profiling of Organic Thin Films Using C<sub>60</sub> Sputtering

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    A buckminsterfullerene (C60) ion beam was used for X-ray photoelectron spectrometry depth profiling of various organic thin films. Specimens representing different interfaces in organic light-emitting diode devices, including hole-conducting poly(ethylenedioxythiophene), poly(styrenesulfonic acid) (PEDOT:PSS) thin films on ITO with and without polysilicic acid doping, light-emitting Ir-containing 4,4‘-bis(carbazol-9-yl)biphenyl (CBP) molecules on PEDOT:PSS, and electron-conducting 2,2‘,2‘ ‘(1,3,5-benzinetriyl)tris(1-phenyl-1-H-benzimidazole) (TPBi) molecules on CBP, were studied. In all cases, a clear multilayer structure was observed. The chemical composition and elemental state were preserved after C60+ ion sputtering. The sputter rate was found to decrease with sputtering time. This is due to the deposition of amorphous carbon on the surface, with the rate of implantation highly dependent on the surface interacting with the ion beam

    Table3_The association between mortality and use of Chinese herbal medicine among incident stage IV esophageal cancer patients: A retrospective cohort study with core herbs exploration.XLSX

    No full text
    Esophageal cancer (EC) remains a leading cause of death worldwide and in Taiwan. The prognosis of advanced-stage EC is notably poor, and the treatment options are limited. Chinese herbal medicine (CHM) has been widely used as a complementary treatment for cancer, yet the long-term effect of CHM in stage IV EC remains unclear.The multi-institutional cohort obtained from the Chang Gung research database (CGRD) was used to study the long-term outcome of CHM use among incident stage IV EC patients from 1 January 2002, to 31 December 2018. All patients were followed up to 5 years or the occurrence of death. The overall survival (OS) and disease-specific survival rates were conducted using Kaplan-Meier estimation. Overlap weighing and landmark analysis were used to eliminate confounding and immortal time biases. Furthermore, we demonstrated the core CHMs for stage IV EC by using the Chinese herbal medicine network (CMN) analysis on prescriptions.Nine hundred eighty-five stage IV EC patients were analyzed, including 74 CHM users and 911 non-CHM users. We found the use of CHM was associated with a higher 5-year overall survival rate than CHM nonusers (the cumulative probability: 19.52% versus 6.04%, log-rank test: p The use of CHM seems safe and possibly beneficial among stage IV EC patients with a higher 5-year OS. Further clinical trials on CHM were guaranteed to explore the role of CHM in managing stage IV EC patients.</p

    Depth Profiling of Organic Films with X-ray Photoelectron Spectroscopy Using C<sub>60</sub><sup>+</sup> and Ar<sup>+</sup> Co-Sputtering

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    By sputtering organic films with 10 kV, 10 nA C60+ and 0.2 kV, 300 nA Ar+ ion beams concurrently and analyzing the newly exposed surface with X-ray photoelectron spectroscopy, organic thin-film devices including an organic light-emitting diode and a polymer solar cell with an inverted structure are profiled. The chemical composition and the structure of each layer are preserved and clearly observable. Although C60+ sputtering is proven to be useful for analyzing organic thin-films, thick organic-devices cannot be profiled without the low-energy Ar+ beam co-sputtering due to the nonconstant sputtering rate of the C60+ beam. Various combinations of ion-beam doses are studied in this research. It is found that a high dosage of the Ar+ beam interferes with the C60+ ion beam, and the sputtering rate decreases with increasing the total ion current. The results suggest that the low-energy single-atom projectile can disrupt the atom deposition from the cluster ion beams and greatly extend the application of the cluster ion-sputtering. By achievement of a steady sputtering rate while minimizing the damage accumulation, this research paves the way to profiling soft matter and organic electronics
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