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[en] The thermal process of wastes with higher calorific value by pyrolysis is reviewed to recover the value added three by-products; a pyrolytic char, a pyrolytic oil, and a non-condensable gas. These by-products from pyrolysis of the waste is converted for electricity power and thermal energy thru gasification process as well as waste heat recovery process. The energy resource and several processes in the integrated pyrolysis gasification combined cycle for waste treatment are investigated with the conceptual design in using the obtained operation data from the pyrolysis pilot, demonstration and commercial plant.
[en] We report on physical vapor deposition of indium sulfide (In2S3) buffer layers and its application to Cu(In,Ga)Se2 (CIGSe) thin film solar cell. The Indium sulfide buffer layers were evaporated onto CIGSe at various substrate temperatures from room temperature (RT) to 350 ◦C. The effect of deposition temperature of buffer layers on the solar cell device performance were investigated by analyzing temperature dependent current-voltage (J-V -T), external quantum efficiency (EQE) and Raman spectroscopy. The fabricated device showed the highest power conversion efficiency of 6.56% at substrate temperature of 250 ◦C, which is due to the decreased interface recombination. However, the roll-over in J-V curves was observed for solar cell device having buffer deposited at substrate temperature larger than 250 ◦C. From the measurement results, the interface defect and roll-over related degradation were found to have limitation on the performance of solar cell device.
[en] We report on direct imaging of current collection by performing conductive atomic force microscopy (C-AFM) measurement on a complete Cu(In,Ga)Se2 solar cell. The localized current was imaged by milling away the top conductive layer of the device by repeated C-AFM scans. The result exhibits enhanced photocurrent collection on grain boundaries (GBs) of CIGS films, consistent with the argument for electric-field-assisted carrier collection on the GBs
[en] Highlights: • An indiscrete layer enabled the suppression of the overly rich Zn zone. • It prevents the formation of Zn-rich detrimental secondary phases and defects. • A sample with 15 precursor layers exhibits a shallow acceptor energy level. To commercialize Cu2ZnSn(S,Se)4 (CZTSSe) thin-film solar cells, it is necessary to improve their efficiency and to develop the technological ability to produce large-area modules. Defect formation due to the secondary phase is considered to be one of the main reasons for decreased CZTSSe thin-film solar-cell efficiency. This study explores the potential capabilities of large-area thin-film solar cells by controlling the defect formation using various CZTSSe precursor designs, and by improving the characteristic uniformity within the thin-film solar cells. Alloying the precursor as a stack of discrete layers can result in lateral segregation of elements into stable-phase islands, yielding a non-uniform composition on small length scales. It is found that the application of an indiscrete layer by minimizing the precursor-layer thickness allows avoiding Zn rich inhomogeneities in the absorber that would favor formation of detrimental ZnS-ZnSe secondary phases and deep defects. Among the various precursor layers designed by considering the reaction mechanism under annealing, a sample with 15 precursor layers is found to exhibit a shallow electron-acceptor energy level, high photovoltaic conversion efficiency, and uniform characteristics over the corresponding thin-film solar cell. Based on such improvements in both the efficiency and characteristic distribution, it is expected that the commercialization of CZTSSe thin-film solar cells can be advanced.