Abstract
For kesterite copper zinc tin sulfide/selenide (CZTSSe) solar cells to enter the market, in addition to efficiency improvements, the technological capability to produce flexible and ...large-area modules with homogeneous properties is necessary. Here, we report a greater than 10% efficiency for a cell area of approximately 0.5 cm
2
and a greater than 8% efficiency for a cell area larger than 2 cm
2
of certified flexible CZTSSe solar cells. By designing a thin and multi-layered precursor structure, the formation of defects and defect clusters, particularly tin-related donor defects, is controlled, and the open circuit voltage value is enhanced. Using statistical analysis, we verify that the cell-to-cell and within-cell uniformity characteristics are improved. This study reports the highest efficiency so far for flexible CZTSSe solar cells with small and large areas. These results also present methods for improving the efficiency and enlarging the cell area.
Improving the efficiency of kesterite (Cu2ZnSn(S,Se)4; CZTSSe) solar cells requires understanding the effects of Na doping. This paper investigates these effects by applying a NaF layer at various ...positions within precursors. The NaF position is important because Na produces Na‐related defects in the absorber and suppresses the formation of intrinsic defects. By investigating precursors with various NaF positions, the sulfo‐selenization mechanism and the characteristics of defect formation are confirmed. Applying a NaF layer onto a Zn layer in a CZTSSe precursor limits Zn diffusion and suppresses Cu‐Zn alloy formation, thus changing the sulfo‐selenization mechanism. In addition, the surface NaF layer provides reactive Se and S to the absorber layer by generating Na2Sex and Na2Sx liquid phases during sulfo‐selenization, thus limiting the incorporation of Na into the absorber and reducing the Na effects. Efficiency values of 11.16% and 11.19% are obtained for a flexible CZTSSe solar cell by applying NaF between the Zn layer and back contact and between the Cu and Sn layers, respectively. This study presents methods for doping with alkali metals and improving the efficiency of photovoltaics.
Applying the NaF layer on a Zn layer in a CZTSSe precursor limits the diffusion of Zn and suppresses the formation of a Cu‐Zn alloy. An efficiency of 11.19% is obtained for the flexible CZTSSe solar cell by applying the NaF between the Cu and Sn layers.
The widespread of carbapenem-resistant
(CRAB) is of great concern in clinical settings worldwide. It is urgent to develop new therapeutic agents against this pathogen. This study aimed to evaluate ...the therapeutic potentials of compound 62520, which has been previously identified as an inhibitor of the
promoter activity of
, against CRAB isolates, both in vitro and in vivo. Compound 62520 was found to inhibit the
expression and biofilm formation in
ATCC 17978 at sub-inhibitory concentrations in a dose-dependent manner. These inhibitory properties were also observed in clinical CRAB isolates belonging to sequence type (ST) 191. Additionally, compound 62520 exhibited a bacteriostatic activity against clinical clonal complex (CC) 208 CRAB isolates, including ST191, and ESKAPE pathogens. This bacteriostatic activity was not different between STs of CRAB isolates. Bacterial clearance was observed in mice infected with bioimaging
strain 24 h after treatment with compound 62520. Compound 62520 was shown to significantly increase the survival rates of both immunocompetent and neutropenic mice infected with
ATCC 17978. This compound also increased the survival rates of mice infected with clinical CRAB isolate. These results suggest that compound 62520 is a promising scaffold to develop a novel therapeutic agent against CRAB infections.
In recent years, Cu2ZnSn(S1-xSex)4 (CZTSSe) prepared by a two-step process using metal precursors has been reported to exhibit a relatively high power conversion efficiency, and a high efficiency of ...12.5% by two-step process contained via sputtering method was recently confirmed by our group. In this study, we proposed formation mechanisms for the CZTSSe double layer, voids and ZnSSe layer, which were observed in the CZTSSe using metal precursor. Due to the persistent dezincification from the metal precursors and preferential reaction between the Zn and chalcogens such as S and Se, almost all Zn is consumed to form the ZnSSe layer; as a result, large voids are produced first under the ZnSSe layer. Cu2Se and SnSe are grown on the ZnSSe layer via migration of the Cu and Sn through the grain boundaries of the ZnSSe layer. Thus, additional small voids are expected to form due to the mass transfer of Cu and Sn. Because of the preferentially formed ZnSSe layer and the chalcogenation of Cu and Sn after the mass transfer, a CZTSSe double layer can be formed, and ZnSSe can exist between these CZTSSe layers. Finally, we propose a method based on the formation mechanism to control the voids and secondary phases, which affect the fill factor and output current.
The new formation mechanisms of the voids, ZnSSe layer and CZTSSe double layer that were observed in the sister sample of 12.5% of CZTSSe cell. Display omitted
•The new formation mechanisms of the voids, ZnSSe layer and CZTSSe double layer that were observed in the sister sample of 12.5% of CZTSSe cell.•Large voids are produced under the ZnSSe layer due to the persistent dezincification and preferential reaction between the Zn and chalcogens.•Additional small voids are expected to form due to the migration of Cu and Sn from under the ZnSSe layer to above ZnSSe layer.•Due to the preferentially formed ZnSSe layer and Cu and Sn migration, ZnSSe secondary phase exists between the CZTSSe double layers.
Bicyclic nitroimidazoles, including PA-824, are exciting candidates for the treatment of tuberculosis. These prodrugs require intracellular activation for their biological function. We found that ...Rv3547 is a deazaflavin-dependent nitroreductase (Ddn) that converts PA-824 into three primary metabolites; the major one is the corresponding des-nitroimidazole (des-nitro). When derivatives of PA-824 were used, the amount of des-nitro metabolite formed was highly correlated with anaerobic killing of Mycobacterium tuberculosis (Mtb). Des-nitro metabolite formation generated reactive nitrogen species, including nitric oxide (NO), which are the major effectors of the anaerobic activity of these compounds. Furthermore, NO scavengers protected the bacilli from the lethal effects of the drug. Thus, these compounds may act as intracellular NO donors and could augment a killing mechanism intrinsic to the innate immune system.
In this study, a 5-nm thick Al2O3 layer was patterned onto the Mo electrode in the form of a dot to produce a local rear contact, which looked at the effects of this contact structure on ...Cu2ZnSn(S1-xSex)4 (CZTSSe) growth and solar cell devices. Mo was partially exposed through open holes having a square dot shape, and the closed-ratios of Al2O3 passivated areas were 56%, 75%, and 84%. The process of synthesizing CZTSSe is the same as that of the previous process showing 12.62% efficiency. When the 5-nm-Al2O3 dot patterning was applied to the Mo surface, we observed that the MoSSe formation was well suppressed under the area coated of 5-nm-Al2O3 film. The self-alignment phenomenon was observed in the back-contact area. CZTSSe was easily formed in the Mo-exposed area, while voids were formed near the Al2O3-coated area. The efficiency of the CZTSSe solar cell decreased when the Al2O3 passivated area increased. The exposure area and pitch of Mo, the collecting path of the hole, and the supplying path of Na seemed to be related to efficiency. Thus, it was suggested that the optimization of the Mo-exposed pattern and the additional Na supply are necessary to develop the optimum self-aligned CZTSSe light absorber.
In this study, we investigated the effect of the stacking order of metal precursors on the formation of volume defects, such as blisters and nanopores, in CZTSSe thin-film solar cells. We fabricated ...CZTSSe thin films using three types of metal-precursor combinations, namely, Zn/Cu/Sn/Mo, Cu/Zn/Sn/Mo, and Sn/Cu/Zn/Mo, and studied the blister formation. The blister-formation mechanism was based on the delamination model, taking into consideration the compressive stress and adhesion properties. A compressive stress could be induced during the preferential formation of a ZnSSe shell. Under this stress, the adhesion between the ZnSSe film and the Mo substrate could be maintained by the surface tension of a metallic liquid phase with good wettability, or by the functioning of ZnSSe pillars as anchors, depending on the type of metal precursor used. Additionally, the nanopore formation near the back-contact side was found to be induced by the columnar microstructure of the metal precursor with the Cu/Zn/Mo stacking order and its dezincification. Based on the two volume-defect-formation mechanisms proposed herein, further development of volume-defect-formation suppression technology is expected to be made.
Elevated expression of transmembrane serine protease 4 (TMPRSS4) correlates with poor prognosis in non-small cell lung cancer, gastric cancer, colorectal cancer, prostate cancer, and other cancer ...patients. Previously, we demonstrated that TMPRSS4 mediates tumor cell invasion, migration, proliferation, and metastasis. In addition, we reported novel 2-hydroxydiarylamide derivatives, IMD-0354 and KRT1853, as TMPRSS4 serine protease inhibitors. Here, we further evaluated the effects of the representative derivatives on TMPRSS4-mediated cellular function and signaling. IMD-0354 and KRT1853 inhibited cancer cell invasion, migration, and proliferation in TMPRSS4-expressing prostate, colon, and lung cancer cells. Both compounds suppressed TMPRSS4-mediated induction of Sp1/3, AP-1, and NF-κB transcription factors. Furthermore, TMPRSS4 promoted cancer cell survival and drug resistance, and both compounds enhanced anoikis sensitivity as well as reduced bcl-2 and survivin levels. Importantly, KRT1853 efficiently reduced tumor growth in prostate and colon cancer xenograft models. These results strongly recommend KRT1853 for further development as a novel anti-cancer agent.
Recently, highly efficient CZTS solar cells using pure metal precursors have been reported, and our group created a cell with 12.6% efficiency, which is equivalent to the long-lasting world record of ...IBM. In this study, we report a new secondary phase formation mechanism in the back contact interface. Previously, CZTSSe decomposition with Mo has been proposed to explain the secondary phase and void formation in the Mo-back contact region. In our sulfo-selenization system, the formation of voids and secondary phases is well explained by the unique wetting properties of Mo and the liquid metal above the peritectic reaction (η-Cu6Sn5 → ε-Cu3Sn + liquid Sn) temperature. Good wetting between the liquid Sn and the Mo substrate was observed because of strong metallic bonding between the liquid metal and Mo layer. Thus, some ε-Cu3Sn and liquid Sn likely remained on the Mo layer during the sulfo-selenization process, and Cu–SSe and Cu–Sn–SSe phases formed on the Mo side. When bare soda lime glass (SLG) was used as a substrate, nonwetting adhesion was observed because of weak van der Walls interactions between the liquid metal and substrate. The Cu–Sn alloy did not remain on the SLG surface, and Cu–SSe and Cu–Sn–SSe phases were not observed after the final sulfo-selenization process. Additionally, Mo/SLG substrates coated with a thin Al2O3 layer (1–5 nm) were used to control secondary phase formation by changing the wetting properties between Mo and the liquid metal. A 1 nm Al2O3 layer was enough to control secondary phase formation at the CZTSSe/Mo and void/Mo interfaces, and a 2 nm Al2O3 layer was enough to perfectly control secondary phase formation at the Mo interface and Mo–SSe formation.
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