Search

Cu2Ni0·05Zn0·95Sn(S,Se)4 (CNZTSSe) films were synthesized on Mo-coated glass substrates by the simple sol–gel means combined with the selenization process, and CNZTSSe-based solar cells were successfully prepared. The effects of selenization temperature on the performance and the photoelectric conversion efficiency (PCE) of the solar cells were systematically studied. The results show that the crystallinity of films increases as the selenization temperature raises based on nickel (Ni) doping. When the selenization temperature reached 540 °C, CNZTSSe films with a large grain size and a smooth surface can be obtained. The Se doping level gradually increased, and Se occupied the S position in the lattice as the selenization temperature was increased so that the optical band gap (Eg) of the CNZTSSe film could be adjusted in the range of 1.14 to 1.06 eV. In addition, the Ni doping can inhibit the deep level defect of SnZn and the defect cluster [2CuZn + SnZn]. It reduces the carrier recombination path. Finally, at the optimal selenization temperature of 540 °C, the open circuit voltage (Voc) of the prepared device reached 344 mV and the PCE reached 5.16%. [ABSTRACT FROM AUTHOR]

This study presents a theoretical model and an experimental investigation of a piston engine driven by compressed air. The compressed air engine (CAE) is proposed which is modified from a conventional internal combustion engine. The experiments in this study have used a test bench to examine the output torque and power performance and pressure variations of CAE at different port timing. The study has found that port timing has a direct influence on the working performances of CAE. Based on the theoretical analysis, the model of CAE developed for engine performance analysis and working process is described in this paper. In addition, good agreement of simulation results is obtained between the model and the test. The results show that, as intake advance angle increases, the cylinder pressure decreases during the expansion stroke stage and the exhaust stroke stage. An increase of cylinder pressure is shown at larger intake sustain angle. Moreover, one can find that compared with exhaust advance angle, the intake advance angle and the intake sustain angle have more influence on output torque and power. Consequently, this study of this paper will provide a theoretical and an experimental basis for further study on optimizing the design of CAE. [ABSTRACT FROM AUTHOR]

The near-threshold photoproduction of J / ψ is regarded as one golden process to unveil the nucleon mass structure, pentaquark state involving the charm quarks, and the poorly constrained gluon distribution of the nucleon at large x ( > 0.1 ). In this paper, we present an analysis of the current experimental data under a two-gluon exchange model, which shows a good consistency. Using a parameterized function form with three free parameters, we have determined the nucleonic gluon distribution at the J / ψ mass scale. Moreover, we predict the differential cross-section of the electroproduction of J / ψ as a function of the invariant mass of the final hadrons W, at EicC, as a practical application of the model and the obtained gluon distribution. According to our estimation, hundreds of J / ψ events can be detected per year on EicC near the threshold. Therefore, the relevant experimental measurements are suggested to be carried out on EicC. [ABSTRACT FROM AUTHOR]

In this study, we prepared Na-doped Cu2ZnSn(S,Se)4 [noted as (Na0.1Cu0.9)2ZnSn(S,Se)4] films on the Mo substrate using a simple and cheap sol–gel method together with the post-annealing technique. The effects of selenization temperature on the properties of Na-doped Cu2ZnSn(S,Se)4 were surveyed. The results indicated that some sulfur atoms in the films were substituted by selenium atoms by increasing the selenization temperature, and all films selenized at different temperatures had a kesterite structure. As the selenization temperature increased from 520 to 560 °C, the band gaps of the film can be tuned from 1.03 to 1 eV. The film with better morphology and opto-electrical properties can be obtained at an intermediate selenization temperature range (e.g., 540 °C), which had the lowest resistivity of 47.7 Ω cm, Hall mobility of 4.63 × 10−1 cm2/Vs, and carrier concentration of 2.93 × 1017 cm−3. Finally, the best power conversion efficiency (PCE) of 4.82% was achieved with an open circuit voltage (Voc) of 338 mV, a short circuit current density (Jsc) of 27.16 mA/cm2 and a fill factor (FF) of 52.59% when the selenization temperature was 540 °C. [ABSTRACT FROM AUTHOR]