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Implementing bifacial photovoltaic devices based on transparent conducting oxides (TCO) as the front and back contacts is highly appealing to improve the efficiency of kesterite solar cells. The p-type In substituted Cu2ZnSnS4 (CZTIS) thin-film solar cell absorber has been fabricated on ITO glass by sulfurizing coelectroplated Cu-Zn-Sn-S precursors in H2S (5 vol %) atmosphere at 520 °C for 30 min. Experimental proof, including X-ray diffraction, Raman spectroscopy, UV-vis-NIR transmission/reflection spectra, PL spectra, and electron microscopies, is presented for the interfacial reaction between the ITO back contact and CZTS absorber. This aggressive reaction due to thermal processing contributes to substitutional diffusion of In into CZTS, formation of secondary phases and electrically conductive degradation of ITO back contact. The structural, lattice vibrational, optical absorption, and defective properties of the CZTIS alloy absorber layer have been analyzed and discussed. The new dopant In is desirably capable of improving the open circuit voltage deficit of kesterite device. However, the nonohmic back contact in the bifacial device negatively limits the open circuit voltage and fill factor, evidencing by illumination-/temperature-dependent J-V and frequency-dependent capacitance-voltage (C-V-f) measurements. A 3.4% efficient solar cell is demonstrated under simultaneously bifacial illumination from both sides of TCO front and back contacts.

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The vapor transport deposition of quasi‐one‐dimensional antimony selenosulfide (Sb2(S,Se)3) has recently attracted increasing research interest for the inexpensive, high‐throughput production of thin film photovoltaic devices. Further improvements in Sb2(S,Se)3 solar cell performance urgently require the identification of processing strategies to control the orientation, however the growth mechanism of high quality absorbers is still not completely clear. Herein, a facile and general vapor transport deposition approach to precisely control the growth of large‐grained dense Sb2(S,Se)3 films with good crystallization and preferred orientation via the source vapor speed is utilized. It is found that defect activation energy rather than the defect concentration plays a decisive role in the Sb2(S,Se)3 photovoltaic performance. Admittance spectroscopy analysis is used to obtain efficient Sb2(S,Se)3 solar cells. By employing dual‐source coordinations to optimize the absorber layer a power conversion efficiency of 8.17% is obtained which is the highest efficiency for Sb2(S,Se)3 solar cells fabricated by vapor transport technology. This study suggests that there are other opportunities for gaining deeper a understanding of the defect physics and carrier recombination mechanisms in other highly oriented low‐dimensional materials to achieve improved device performance.

This paper addresses the problem of mapping an application, which is highly dynamic in the future, onto a heterogeneous multiprocessor platform in an energy efficient way. A two-phase scheduling method is used for that purpose. By exploring the Pareto curves and scenarios generated at design time, the run-time scheduler can easily find a good scheduling at a very low overhead, satisfying the system constraints and minimizing the energy consumption. A real-life example from a 3D quality of service kernel is used to show the effectiveness of our method.

Cu2ZnSnS4 thin films with thicknesses ranging from 0.35 to 1.85 μm and micron-sized grains (0.5-1.5 μm) were synthesized using co-electrodeposited Cu-Zn-Sn-S precursors with different deposition times. Here we have introduced a sputtered CdS buffer layer for the development of CZTS solar cells for the first time, which enables breakthrough efficiencies up to 6.6%.

Earth-abundant material, kesterite Cu2ZnSnS4 (CZTS), demonstrates the tremendous potential to serve as the absorber layer for the bifacial thin-film solar cell. The exploration of appropriate sulfurization conditions including annealing temperature is significant to gain insight into the growth mechanism based on the substrates using transparent conductive oxides (TCO) and improve device performance. The kesterite solar absorbers were fabricated on ITO substrates by sulfurizing co-electroplated Cu-Zn-Sn-S precursors in argon diluted H2S atmosphere at different temperatures (475-550 °C) for 30 min. Experimental proof, including cross-section scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, UV-vis-NIR transmission spectrum, and Raman and far-infrared spectroscopy, is presented for the crystallization of CZTS on an ITO substrate and the interfacial reaction between the ITO back contact and CZTS absorber. The complete conversion of precursor into CZTS requires at least 500 °C sulfurization temperature. The aggressive interfacial reaction leading to the out-diffusion of In into CZTS to a considerable extent, formation of tin sulfides, and electrically conductive degradation of ITO back contact occurs at the sulfurization temperatures higher than 500 °C. The bifacial devices obtained by 520 °C sulfurization exhibit the best conversion efficiencies and open circuit voltages. However, the presence of non-ohmic back contact (secondary diode), the short minority lifetime, and the high interfacial recombination rates negatively limit the open circuit voltage, fill factor, and efficiency, evidenced by illumination/temperature-dependent J-V, frequency-dependent capacitance-voltage (C-V-f), time-resolved PL (TRPL), and bias-dependent external quantum efficiency (EQE) measurements.