Investigation of solar cells and phototransistors based on hybrid copper (I) thiocyanate: methanofullerene materials

The combination of organic and inorganic semiconductors offers a route to the development of solar cells and other optoelectronic devices that combine flexibility, high efficiency and high stability. In this thesis, we have investigated the hybrid organic: inorganic system, copper (I) thiocyanate (CuSCN): phenyl C71 butyric methyl acid ester (PC70BM). We have shown that ~100 nm long CuSCN nanowires can be grown within PC70BM when a layer of PC70BM containing dilute CuSCN is deposited on top of a CuSCN layer on a heated substrate. Photovoltaic devices made from these nanowire-containing layers perform significantly better than devices made from CuSCN/PC70BM bilayers because the nanowires improve charge collection efficiency. The initial device based on a nanowire-containing CuSCN:PC70BM structure, the device shows ~5% power conversion efficiency. We show that these CuSCN NWs form well when the substrate temperature is about 115oC. We then discovered that by spin-coating interlayers with a CuSCN rich precursor solution between the compact CuSCN layer and CuSCN:PC70BM photoactive mixed layer, the power conversion efficiency could be further improved to nearly 6% power conversion efficiency. Finally, we measured the carrier mobility of CuSCN:PC70BM layer using field-effect transistors. We find the carrier mobility values for holes and electrons to be on the order of 10-3 to 10-2 cm2/Vs, similar to values for typical organic semiconducting materials. We have also characterized the same device as a phototransistor by illuminating the active area with light in the visible range. This work has demonstrated the concept of the initial application of CuSCN nanowires, which has never been reported in any organic: inorganic mixed layer. CuSCN nanowires could be a new approach for optimizing charge separation in light-absorbing acceptor systems.Open Acces

Angular distributions in the radiative decays of the 3D3^3D_3 state of charmonium originating from polarized pˉp\bar{p}p collisions

Using the helicity formalism, we calculate the combined angular distribution function of the two gamma photons ($\gamma_1$ and $\gamma_2$) and the electron ($e^-$) in the triple cascade process $\bar{p}p\rightarrow{}^3D_3\rightarrow{}^3P_2+\gamma_1\rightarrow(\psi+\gamma_2) +\gamma_1 \rightarrow (e^- + e^+) +\gamma_2 +\gamma_1$, when $\bar{p}$ and $p$ are arbitrarily polarized. We also derive six different partially integrated angular distribution functions which give the angular distributions of one or two particles in the final state. Our results show that by measuring the two-particle angular distribution of $\gamma_1$ and $\gamma_2$ and that of $\gamma_2$ and $e^-$, one can determine the relative magnitudes as well as the relative phases of all the helicity amplitudes in the two charmonium radiative transitions ${}^3D_3\rightarrow{}^3P_2+\gamma_1$ and $^3P_2\rightarrow \psi+\gamma_2$.Comment: arXiv admin note: substantial text overlap with arXiv:1311.464

Angular distributions of the polarized photons and electron in the decays of the 3D3^3D_3 state of charmonium

We calculate the combined angular distribution functions of the polarized photons ($\gamma_1$ and $\gamma_2$) and electron ($e^-$) produced in the cascade process $\bar{p}p\rightarrow$ $^3D_3\rightarrow$ $^3P_2+\gamma_1\rightarrow$ $(\psi+\gamma_2)+\gamma_1\rightarrow(e^++e^-)+\gamma_1+\gamma_2$, when the colliding $\bar{p}$ and $p$ are unpolarized. Our results are independent of any dynamical models and are expressed in terms of the spherical harmonics whose coefficients are functions of the angular-momentum helicity amplitudes of the individual processes. Once the joint angular distribution of ($\gamma_1$, $\gamma_2$) and that of ($\gamma_2$, $e^-$) with the polarization of either one of the two particles are measured, our results will enable one to determine the relative magnitudes as well as the relative phases of all the angular-momentum helicity amplitudes in the radiative decay processes $^3D_3\rightarrow$ $^3P_2+\gamma_1$ and $^3P_2\rightarrow\psi+\gamma_2$

Why do sulfone-containing polymer photocatalysts work so well for sacrificial hydrogen evolution from water?

Many of the highest-performing polymer photocatalysts for sacrificial hydrogen evolution from water have contained dibenzo[b,d]thiophene sulfone units in their polymer backbones. However, the reasons behind the dominance of this building block are not well understood. We study films, dispersions, and solutions of a new set of solution-processable materials, where the sulfone content is systematically controlled, to understand how the sulfone unit affects the three key processes involved in photocatalytic hydrogen generation in this system: light absorption; transfer of the photogenerated hole to the hole scavenger triethylamine (TEA); and transfer of the photogenerated electron to the palladium metal co-catalyst that remains in the polymer from synthesis. Transient absorption spectroscopy and electrochemical measurements, combined with molecular dynamics and density functional theory simulations, show that the sulfone unit has two primary effects. On the picosecond timescale, it dictates the thermodynamics of hole transfer out of the polymer. The sulfone unit attracts water molecules such that the average permittivity experienced by the solvated polymer is increased. We show that TEA oxidation is only thermodynamically favorable above a certain permittivity threshold. On the microsecond timescale, we present experimental evidence that the sulfone unit acts as the electron transfer site out of the polymer, with the kinetics of electron extraction to palladium dictated by the ratio of photogenerated electrons to the number of sulfone units. For the highest-performing, sulfone-rich material, hydrogen evolution seems to be limited by the photogeneration rate of electrons rather than their extraction from the polymer

Polysaccharopeptide enhances the anticancer activity of doxorubicin and etoposide on human breast cancer cells ZR-75-30

In search of natural bioactive microbial compounds with adjuvant properties, we have previously showed that the polysaccharopeptide (PSP), isolated from Chinese medicinal mushroom Coriolus versicolor, was able to enhance the cytotoxicity of certain S-phase targeted-drugs on human leukemic HL-60 cells via some cell-cycle and apoptotic-dependent pathways. The present study aimed to investigate whether the synergism of mechanisms of PSP with certain chemotherapeutic drugs also applies to human breast cancer. PSP treatment enhanced the cytotoxicity of doxorubicin (Doxo), etoposide (VP-16) but not cytarabine (Ara-C). Bivariate bromodeoxyuridine (BrdUrd)/DNA flow cytometry analysis estimated a longer DNA synthesis time (Ts) for the PSP treated cancerous cells suggesting that PSP enhanced the apoptotic effect of Doxo and VP-16 via creating an S-phase trap in the human breast cancer cell line ZR-75-30. The participation of PSP in the apoptotic machinery of the chemotherapeutic agents was further supported by a reduced ratio of protein expression of Bcl-xL/Bax of the cancer cells. This study provides further insight into the synergistic mechanisms of PSP and supports the hypothesis that the anticancer potentials of PSP is not limited to leukemia but may also be used as an adjuvant therapy for breast cancers

性別與女性 = Gender and women

第一節由MCS畢業生胡世君主持，分別由劉健仁主講《國家建立與太平天國的婦女》，何蕙雯主講 Language and Gender Construction ，余曉瑉主講 Why & How Women liberate themselves under literary paternity?: the representations of women’s liberation in The Hours by Michael Cunningham and the colour purple by Alice Walker ，並由薛翠博士擔任評論及與講者進行討論

Exercise capacity and its determinants among postcardiac rehabilitation patients with coronary heart disease

Abstract Aim To investigate the determinants of exercise capacity in postcardiac rehabilitation patients with coronary heart disease (CHD). Design A cross‐sectional design was used. Methods This study analysed the cross‐sectional data from the baseline assessment of 130 CHD patients who participated in a longitudinal randomized controlled trial of music‐paced physical activity intervention for CHD patients (ChiCTR‐IOR‐17011015) (September 2017 to February 2019). Exercise capacity was measured by using the 10‐metre incremental shuttle‐walk test. The amount of physical activity, exercise self‐determination and exercise self‐efficacy were measured by validated instruments. Participants' anthropometric parameters (body mass index, body fat mass percentage and waist circumference) were measured. Hierarchical regression analyses were used to identify the factors influencing exercise capacity. Results The mean incremental shuttle‐walk test distance was 493.00 ± 180.04 m. The factors significantly associated with exercise capacity were age (β = −.42), female (β = −.35), body mass index (β = −.25) and exercise self‐efficacy (β = −.20). These factors accounted for 56.5% of the total variance of exercise capacity

Children with Physical Disabilities at School and Home: Physical Activity and Contextual Characteristics

The purpose of this study was to assess the physical activity (PA) of children with physical disabilities (PD) in school and home settings and to simultaneously examine selected contextual characteristics in relation to PA in those settings. Children with PD (N = 35; Mean age = 15.67 ± 4.30 years; 26 boys) were systematically observed using BEACHES (Behaviors of Eating and Activity for Children’s Health: Evaluation System) at school (before school, recess, lunch break, after class) and at home (before dinner) during four normal school days. The children spent most of their time in all five settings being physically inactive, but had slightly more PA during recess and lunch break periods. Hierarchical multiple regression revealed that selected contextual characteristics explained 18.9–56.0% (p < 0.01) of the variance predicting moderate-to-vigorous physical activity (MVPA) after controlling for demographic variables. Prompts to be active were positively associated with MVPA at school and the presence of fathers and fathers being motivators at home. This study highlights how little PA that children with PD receive and identifies the importance of the provision of prompts for PA at both school and home with this special population

Why do sulfone-containing polymer photocatalysts work so well for sacrificial hydrogen evolution from water?

In recent years, many of the highest performing polymer photocatalysts for hydrogen evolution from water have contained dibenzo[b,d]thiophene sulfone units in their polymer backbones. However, the reasons behind the dominance of this building block are not well understood. We use a new set of processable materials, in which the sulfone content is systematically controlled, to understand how the sulfone unit affects the three key processes involved in photocatalytic hydrogen generation in this system: light absorption; transfer of the photogenerated hole to the hole scavenger triethylamine (TEA); and transfer of the photogenerated electron to the palladium metal co-catalyst that remains in the polymer from synthesis. Using transient absorption spectroscopy and electrochemical measurements, and combined with molecular dynamics and density functional theory simulations, we find that the sulfone unit has two primary effects. On the picosecond timescale, it dictates the thermodynamics of hole transfer out of the polymer. The sulfone unit attracts water molecules such that the average permittivity experienced by the solvated polymer is increased, and we demonstrate here that TEA oxidation is only thermodynamically favourable above a certain permittivity threshold. On the microsecond timescale, we present experimental evidence that the sulfone unit acts as the electron transfer site out of the polymer, with the kinetics of electron extraction to palladium dictated by the ratio of photogenerated electrons to the number of sulfone units. For the highest performing, sulfone-rich material, hydrogen evolution appears to be limited by the photogeneration rate of electrons rather than their extraction from the polymer