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Owing to high theoretical capacity, lithium-sulfur batteries (LSBs) are receiving extensive researches. However, cyclic instability and safety issues hugely confine the commercial applications of traditional liquid LSBs. In this work, for the sake of fully leveraging the high ionic conductivity of polyacrylonitrile while avoiding Li anode "passivation effect" caused by CN group, we prepare double-layer gel polymer electrolytes for quasi-solid-state LSBs. The transition layer composed of polyacrylonitrile, polyethylene oxide and Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP) is located on Li anode side to reduce "passivation effect" triggered by pure polyacrylonitrile. Meanwhile, the high ionic conductivity layer composed of polyacrylonitrile and LATP in contact with cathode can utilize the high intrinsic ionic conductivity of polyacrylonitrile to enhance the rate performance. Furthermore, LATP with higher ionic conductivity embedded in the membrane serves as Li+ transport channels to further increase ionic conductivity. Prominently, the designed double-layer electrolytes exhibit a high Li+ transference number of 0.55 and superior mechanical property. Moreover, stable coulombic efficiency of 99.6–100.0% over 100 cycles and good capacity retention of 79.0% after 100 cycles at 0.1C can be achieved. Our newly designed double-layer electrolytes with multiple functions exhibit potential applications in safer LSBs. Image 1 • The H N hydrogen bond can weaken the "passivation effect" of cyano group. • Two layers in the electrolyte possess different electrochemical functions. • High ionic conductivity layer improves the ionic conductivity of the membrane. • Transition layer protects anode from passivation caused by pure polyacrylonitrile. [ABSTRACT FROM AUTHOR]

Compliant substrates are one of the many promising lattice engineering approaches for hetero-epitaxy. There are many approaches to realize such compliant substrates. Silicon-on-insulator (SOI) wafer is a good option as it is readily available from industry. Previous studies on SOI using silicon thicker than 10 nm on insulator reported limited or no compliance. However, the effect of ultrathin silicon thickness (<10 nm) on the compliance of SOI wafer has not previously been studied. In this work, we investigate the quality of GaAs hetero-epitaxial films on SOI as a function of ultra-thin Si layer thickness. Results show that the quality of GaAs films deposited by Metal-Organic Chemical Vapour Deposition improves with decreasing Si thickness. When Si thickness is <4 nm, the resultant GaAs film is single-crystalline. When Si thickness is >4 nm, the GaAs film is multi-crystalline. These films have been characterized by X-ray diffraction measurement, atomic force microscopy and transmission electron microscopy. These findings show the potential for SOI wafers as compliant substrates at ultrathin Si thicknesses. [ABSTRACT FROM AUTHOR]

Single crystalline Ge-rich Si x Ge 1-x epitaxially grown on a Si substrate is attracting great attention for its potential in optical and electronic device applications. One method of achieving Si x Ge 1-x epitaxy is by aluminium-assisted crystallization although the challenge of controlling the Si content in the Si x Ge 1-x is limited by the furnace annealing process. Herein, we report the use of a diode laser to induce aluminium-assisted crystallization of Si x Ge 1-x on Si with minimal Si content in the Si x Ge 1-x layer. By replacing furnace heat treatment with laser treatment, the reaction time is shortened from minutes to milliseconds which can limit the amount of Si incorporation into the Si x Ge 1-x films. X-ray diffraction, Raman spectroscopy, transmission electron microscopy and X-ray spectroscopy analyses are conducted on the fabricated films revealing the achievement of Ge-rich Si x Ge 1-x on Si through laser-induced aluminium-assisted crystallization. The higher laser dose may slightly increase the Si content and improve the crystallinity of the Si x Ge 1-x films. • First use of laser to induce aluminium-assisted crystallization of Si x Ge 1-x on Si • The laser-induced method reduces the reaction time from minutes to milliseconds • Achievement of Ge-rich Si x Ge 1-x on Si by this laser-induced method • Higher laser dose may improve the crystallinity of Si x Ge 1-x films [ABSTRACT FROM AUTHOR]

In this work, epitaxial Ge films grown on Si by magnetron sputtering were annealed by diode laser as a replacement for conventional thermal annealing to reduce the threading dislocation density (TDD). After laser scans of millisecond exposure time, improvement of crystallinity and increase in tensile strain are observed in the Ge films. TDD of the Ge film is reduced by two orders of magnitude from 10 10 cm − 2 to 10 8 cm − 2 after only three laser scans. Diode laser annealing is a fast and low-cost method to effectively reduce TDD in epitaxial Ge films on Si. [ABSTRACT FROM AUTHOR]

Aluminium-assisted crystallization is used to grow single-crystalline SixGe1−x film epitaxially on Si substrate at a relatively low temperature (350–450°C). Investigation of the mechanism by which Al film causes epitaxial growth of SixGe1−x suggests a four-step growth process is involved. The composition of the SixGe1−x film can be controlled by the annealing conditions. This SixGe1−x film can be used as a buffer layer for the epitaxial growth of Ge on Si or as a virtual substrate for the fabrication of III–V devices. [ABSTRACT FROM AUTHOR]

Theoretical calculation suggests Cu-rich chalcopyrite absorbers contain less defects and have potential to achieve better performance than Cu-poor absorbers. However, this has not been demonstrated due to the detrimental Cu 2-x Se impurity remaining in the absorber. Here, we report highly efficient Cu-rich chalcopyrite solar cells by selenizing dimethylformamide molecular precursor solution processed precursor films under high Ar pressure. Characterizations using XRD, Raman, SEM, TEM, c-AFM, PL, and glow discharge optical emission spectroscopy (GDOES) show high pressure selenization enables high quality Cu-rich chalcopyrite absorber materials with stoichiometric composition, smooth surface, high conductivity, and Cu 2-x Se free grain boundaries, leading to efficient CuIn(S,Se) 2 and Cu(In,Ga)(S,Se) 2 devices with power conversion efficiency of 14.5% and 15.2%, both are the best performing chalcopyrite solar cells from non-hydrazine solutions. Our results demonstrate high Ar pressure selenization is a new strategy to fabricate high quality Cu-rich absorber which has great potential to further improve chalcopyrite solar cell efficiency. CIS solar cell with an efficiency of 14.5% is achieved from Cu-rich ([Cu]/[In] = 1.05) absorber fabricated from DMF molecular solution by high pressure selenization , which is 9.96% for Cu-poor ([Cu]/[In] = 0.85) device. The Cu-rich absorber has stoichiometric composition, smooth surface, high conductivity, and Cu 2-x Se free grain boundaries. This is the first time highly efficient chalcopyrite solar cell is demonstrated from Cu-rich absorbers. Image 1 • Highly efficiency chalcopyrite solar cells are for the first time demonstrated from Cu-rich absorbers. • 15.2% CIGS solar cell is the highest efficiency chalcopyrite solar cell achieved from environmentally benign solvent. • The Cu-rich absorber shows stoichiometric composition, high conductivity, Cu 2-x Se free grain boundary and smooth surface. • High pressure selenization is the key to achieve high quality Cu-rich chalcopyrite absorber. [ABSTRACT FROM AUTHOR]

At present, the quasi-solid-state lithium-sulfur batteries (LSBs) assembled with sulfur cathode, gel polymer electrolyte (GPE) and Li anode have explored a novel prospect for substantial energy applications owing to the high energy density and elevated security. In this work, we propose a 3D ultraviolet polymerized electrolyte, in which the inner substrate is the PEO modified PVDF-HFP electrospun membrane, and the hydrogen bonding effect plays a critical role in regulating the nanofiber diameter and membrane porosity. Simultaneously, outside coating is the in-situ ultraviolet polymerized pentaerythritol tetrakis-divinyl adipate (PETT-DA) layer, in which the carbonyl groups can effectively suppress the polysulfides shuttling. Consequently, the optimal electrolyte membranes with high porosity possess the high electrolyte uptake of 279.8%, ionic conductivity of 9.64 × 10−4 S cm−1 and Li+ transference number of 0.71 at 25 °C. Prominently, the assembled quasi-solid-state LSBs exhibit the stable coulombic efficiency of 99.5–100.0% over 300 cycles and good capacity retention of 87.1% after 300 cycles at 2C. More importantly, excellent thermal dimensional properties and mechanical performances further provide great commercial potentials for our synthesized 3D electrolyte membranes. Image 1 • Substrate and outside coating have good connection and engender synergistic effect. • Inner electrospun nanofiber substrate guarantees the high electrolyte uptake. • Theoretically, hydrogen bonds between PEO and PVDF-HFP play a critical role in controlling the diameter of the nanofibers. • Ultraviolet polymerized coating layer confines shuttle effect due to carbonyl groups. [ABSTRACT FROM AUTHOR]

• Organic carbon addition enhanced denitrification rate and S0 accumulation. • The lowest N 2 O emissions was achieved at Ac−-C/N ratio of 1.3. • Organic carbon influenced nitrate reduction genes, increasing nap A and decreasing nar G. • Isotope fractionation (18ε/15ε) indicated autotrophic or heterotrophic denitrification pathway. • 18ε and 15ε were related to kinetic parameter changes and nitrate reduction genes. Additional organics are generally supplemented in the sulfide-driven autotrophic denitrification system to accelerate the denitrification rate and reduce sulfate production. In this study, different concentrations of sodium acetate (NaAc) were added to the sulfide-driven autotrophic denitrification reactor, and the S0 accumulation increased from 7.8% to 100% over a 120-day operation period. Batch experiments revealed a threefold increase in total nitrogen (TN) removal rate at an Ac−-C/N ratio of 2.8 compared to a ratio of 0.5. Addition of organic carbon accelerated denitrification rate and nitrite consumption, which shortened the emission time of N 2 O, but increased the N 2 O production rate. The lowest N 2 O emissions were achieved at the Ac−-C/N ratio of 1.3. Stable isotope fractionation is a powerful tool for evaluating different reaction pathways, with the 18ε/15ε values in nitrate reduction ranging from 0.5 to 1.0. This study further confirmed that isotope fractionation can reveal denitrifying nutrient types, with the 18ε (isotopic enrichment factor of oxygen)/15ε (isotopic enrichment factor of nitrogen) value approaching 1.0 for autotrophic denitrification and 0.5 for heterotrophic denitrification. Additionally, the 18ε/15ε values can indicate changes in nitrate reductase. There is a positive correlation between the 18ε/15ε values and the abundance of the functional gene nap A, and a negative correlation with the abundance of the gene nar G. Moreover, 18ε and 15ε were associated with changes in kinetic parameters during nitrate reduction. In summary, the combination of functional gene analysis and isotope fractionation effectively revealed the complexities of mixotrophic denitrification systems, providing insights for optimizing denitrification processes. [Display omitted] [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the beneficial effects and underlying mechanism of dietary β-mannanase supplementation on the productive performance of laying hens fed with metabolic energy (ME)-reduced diets. A total of 448 Hy-Line gray laying hens were randomly assigned to seven groups. Each group had 8 replicates with 8 hens. The groups included a control diet (CON) with a ME of 2750 kcal/Kg, diets reduced by 100 kcal/Kg or 200 kcal/Kg ME (ME _100 or ME _200), and diets with 0.15 g/Kg or 0.2 g/Kg β-mannanase (ME _100 +β-M _0.15 , ME _100 +β-M _0.2 , ME _200 +β-M _0.15 , and ME _200 +β-M _0.2). The productive performance, egg quality, intestinal morphology, inflammatory response, mRNA expression related to the Nuclear factor kappa B (NF-κB) and AMPK pathway, and cecum microbiome were evaluated in this study. ME-reduced diets negatively impacted the productive performance of laying hens. However, supplementation with β-mannanase improved FCR, decreased ADFI, and restored average egg weight to the level of the CON group. ME-reduced diets increased the levels of interleukin-1β (IL-1β) and IL-6 while decreasing the levels of IL-4 and IL-10 in the jejunum of laying hens. However, dietary β-mannanase supplementation improved jejunum morphology, reduced pro-inflammatory cytokine concentrations, and increased levels of anti-inflammatory factors in laying hens fed with ME-reduced diets. The mRNA levels of IL-6, IFN-γ, TLR4, MyD88 , and NF-κB in the jejunum of ME-reduced diets were significantly higher than that in CON, dietary β-mannanase supplementation decreased these genes expression in laying hens fed with ME-reduced diets. Moreover, dietary β-mannanase supplementation also decreased the mRNA levels of AMPKα and AMPKγ , and increased the abundance of mTOR in the jejunum of laying hens fed with ME-reduced diets. Cecum microbiota analysis revealed that dietary β-mannanase increased the abundance of various beneficial bacteria (e.g., g_Pseudoflavonifractor, g_Butyricicoccus , and f_Lactobacillaceae) in laying hens fed with ME-reduced diets. In conclusion, dietary β-mannanase supplementation could improve the productive performance of laying hens fed with a ME-reduced diet by improving intestinal morphology, alleviating intestinal inflammation, changing energy metabolism-related signaling pathways, and increasing cecum-beneficial microbiota. [ABSTRACT FROM AUTHOR]

Abstract: Properties of heavily boron-doped hydrogenated polycrystalline germanium (Ge) films sputter-deposited on glass are investigated for developing p+ emitters of the bottom cells of low cost monolithic tandem solar cells. The films were deposited and in-situ doped by co-sputtering Ge with boron at various power levels (P B) in a mixture of argon and hydrogen at 500°C, and then followed by a rapid thermal anneal process at 550°C for 120s or 600°C for 60s, respectively. The dependence of the structural properties of the films on the various boron incorporations as well as annealing conditions was explored by Raman and X-ray diffraction measurements. We find that the films as deposited at 500°C are polycrystalline with strong (220) preferential orientation, which are normally of columnar structure, confirmed by cross-sectional transmission electron microscopy. Revealed by Hall measurements, a boron activation level of 6.24×1019 atoms/cm3, well above reported maximum solid solubility in crystalline Ge, was obtained in the as deposited film at P B=55W. Annealing at 600°C enhanced the concentration to 1.21×1020 atoms/cm3. A fact that boron hardly diffuses in Ge at temperatures below 800°C makes the resultant material an excellent candidate for thin p+ emitters of the bottom cells of monolithic tandem solar cells. [ABSTRACT FROM AUTHOR]

Sb 2 S 3 and CuSbS 2 have been proposed as alternative earth-abundant absorber materials for thin-film solar cells. However, no thermodynamic study of the S−Sb binary system and the Cu−S−Sb ternary system were investigated. In this paper, The S−Sb system and the Cu−S−Sb system are calculated utilizing the so-called CALPHAD (CALculation of PHAse Diagrams) technique. Using TEM-EDS and XRD, Cu 0.9 Sb 1 S 2 is experimentally confirmed at the Cu 1 Sb 1 S 2 and Sb 2 S 3 two-phases region in the isothermal section at 673 K of the Cu−S−Sb ternary system. Given the asymmetric shape and miscibility gap of the liquidus in the S−Sb phase diagram, the associate solution model for the liquid phase is adopted. The solution phases (liquid, bcc, fcc) are treated with the Redlich–Kister equation. The compounds S 3 Sb 2 , Cu 3 SbS 3 , Cu 12 Sb 4 S 13 , CuSbS 2 , and Cu 3 SbS 4 are described as a stoichiometric compound. A set of self-consistent thermodynamic parameters of the S−Sb binary system and the Cu−S−Sb ternary system are obtained. The calculated results are in good agreement with the experimental data. This study provides a set of reliable thermodynamic parameters to the Cu−Sb−S thermodynamic database, and a cost-effective tool to design material synthesis experiments and manufacturing processes. [ABSTRACT FROM AUTHOR]

• Preparation of CZTS thin films via facile and environmentally friendly SILAR method. • Analysis of the effects of different annealing temperature and holding time on film quality. • Fabrication of 4.26% efficiency solar cells by water-based inorganic method. Kesterite Cu 2 ZnSnS 4 (CZTS) solar cells are regarded as a promising photovoltaic technology owing to the non-toxic and earth-abundant constitutes. With the application of scalable and low-cost solution methods, the possibility of its commercialization can be further increased. This work explores preparing prominent CZTS films by an economically feasible successive ionic adsorption and reaction (SILAR) synthesis method. The obtained precursor with the Mo/ZnS/Cu 2 SnS 3 structure requires appropriate substantial annealing under a chalcogen atmosphere to form kesterite CZTS films. The annealing process is therefore optimized to improve the film quality and the performance of solar cells. Specifically, the optimal annealing condition is determined by adjusting the annealing temperature and holding time, respectively. The CZTS film annealed at 580 °C for 60 min demonstrates better film quality in terms of surface morphology, crystallinity, and phase purity. Consequently, CZTS solar cells fabricated with the optimal absorber exhibit a preferable efficiency of up to 4.26%. [ABSTRACT FROM AUTHOR]

• Mixotrophic system showed stable nitrogen removal performance of 94 % under organics stress. • SAD in floc sludge was the primary NO 2 −-N supply pathway for anammox. • Autotrophic subsystem dominated nitrogen removal with anammox contributing to 65.1 %. • Significantly strengthened SSA and SAA were observed with increasing OLR. • SOB and anammox bacteria expressed actively on transcriptional level under high OLR. Sulfur-based autotrophic denitrification (SAD) coupled with anammox is a promising process for autotrophic nitrogen removal in view of the stable nitrite accumulation during SAD. In this study, a mixotrophic nitrogen removal system integrating SAD, anammox and heterotrophic denitrification was established in a single-stage reactor. The long-term nitrogen removal performance was investigated under the intervention of organic carbon sources in real municipal wastewater. With the shortening of hydraulic retention time, the nitrogen removal rate of the mixotrophic system dominated by the autotrophic subsystem reached 0.46 Kg N/m³/d at an organic loading rate of 0.57 Kg COD/m³/d, with COD and total nitrogen removal efficiencies of 82.5 % and 94 %, respectively, realizing an ideal combination of autotrophic and heterotrophic systems. The 15NO 3 −-N isotope labeling experiments indicated that thiosulfate-driven autotrophic denitrification was the main pathway for nitrite supply accounting for 80.6 %, while anammox exhibited strong competitiveness for nitrite under the dual electron supply of sulfur and organic carbon sources and contributed to 65.1 % of nitrogen removal. Sludge granulation created differential functional distributions in different forms of sludge, with SAD showing faster reaction rate as well as higher nitrite accumulation rate in floc sludge, while anammox was more active in granular sludge. Real-time quantitative PCR, RT-PCR and high-throughput sequencing results revealed a dynamically changing community composition at the gene and transcription levels. The decrease in heterotrophic denitrification bacteria abundance indicated the effectiveness of the operational strategy for introduction of thiosulfate and maintaining the dominance of SAD in denitrification process in suppressing the excessive growth of heterotrophic bacteria in the mixotrophic system. The high transcriptional expression of sulfur-oxidizing bacteria (SOB) (Thiobacillus and Sulfurimonas) and anammox bacteria (Candaditus_Brocadia and Candidatus_Kuenenia) played a crucial role in the stable nitrogen removal. [Display omitted] [ABSTRACT FROM AUTHOR]

This review summarizes some emerging inorganic photovoltaic materials including Cu(In,Ga)Se 2 (CIGSe), kesterite Cu 2 ZnSn(S,Se) 4 (CZTSSe), CdTe, Sb 2 Se 3 and inorganic perovskite CsPb(I 1− x Br x) 3. The materials features, development history and performance enhancements for each of solar cells are discussed in detail. The efficient conversion of solar energy to electricity for human utilization heavily relies on the development of solar cells. Nowadays, a variety of high-performance solar cells are constantly emerging. Thin-film solar cells made from inorganic materials have constituted one of the major categories of solar cells showing potential in the fast growing photovoltaic (PV) market. In order to provide an overall grasp of and insight into the future direction of inorganic thin-film solar cell development, we review key emerging and representative inorganic photovoltaic materials including chalcopyrite Cu(In,Ga)Se 2 (CIGSe), kesterite Cu 2 ZnSn(S,Se) 4 (CZTSSe), CdTe, Sb 2 Se 3 and inorganic perovskite CsPb(I 1− x Br x) 3 in this paper. Absorber materials, evolution of device development, and current challenges and key strategies for performance enhancement are detailed. [ABSTRACT FROM AUTHOR]

Abstract NASICON-type LiZr 2 (PO 4) 3 (LZP) has a high bulk ionic conductivity (∼10−4 S cm−1) and a wide electrochemical stability window between 0 and 5.5 V. However, LZP suffers from a problem in which its desirable rhombohedral phase transforms to the triclinic phase (∼10−8 S cm−1) below 50 °C. In this work, we reported a rhombohedral-structured LiZr 2 (PO 4) 3 (α-LZP) at room temperature with a high total Li-ion conductivity (2.8 × 10−6 S cm−1) by a microwave sintering process. Moreover, this approach realized a drastic reduction in the sintering temperature from the typical 1200 °C–900 °C with only a 4 h holding time. Using this approach, we also demonstrated the successful synthesis of Ca-incorporated Li 1.2 Ca 0.1 Zr 1.9 (PO 4) 3 (LCZP) with an ionic conductivity of 1.7 × 10−5 S cm−1. [ABSTRACT FROM AUTHOR]

Abstract A series of ester-bonded gemini pyrrolidinium surfactants 2,2′-((adipoylbis(oxy)) bis(methylene))bis(1-alkyl-1-methylpyrrolidin-1-ium) bromide (abbreviated C n -6-C n , where n = 12, 14, and 16) were synthesized and characterized using 1H NMR, ESI-MS, and IR spectra. Self-aggregation and physicochemical properties between C n -6-C n and their corresponding monomers 2-(hydroxymethyl)-1-methyl-1-alkyl pyrrolidinium bromide (abbreviated C m PB, where m = 12, 14, and 16) were compared using surface tension, electrical conductivity, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The results show that the critical micellar concentration (CMC) values and surface tension at the CMC of the gemini surfactants C n -6-C n are lower than those of the monomeric surfactants C m PB. The conductivity measurement revealed the formation of premicellar aggregates in the C 14 -6-C 14 and C 16 -6-C 16 solution at sufficiently low concentration below their CMC values. DLS and TEM showed that C m PB and C n -6-C n can spontaneously self-assemble into spherical or ellipsoid aggregates, whereas C n -6-C n can form larger aggregates with an increased degree of oligomerization and with longer alkyl chain because of greater hydrophobic interactions. Highlights • Ester-bonded gemini pyrrolidinium surfactants were synthesized and characterized. • Surface properties and aggregation behavior of C n -6-C n and C m PB were investigated. • C n -6-C n have higher surface activity than those of their single-tail analog C m PB. • Ability of C n -6-C n to form premicellar aggregates depends on tail length. [ABSTRACT FROM AUTHOR]

Highlights • DuCV induces primary sclerosing cholangitis (PSC) in natural and reproductive duck cases. • DuCV shows high tropism to epithelial cell of bile duct. • The pathology model of PSC that induced by DuCV sheds light on mechanism of PSC study. Abstract Primary sclerosing cholangitis (PSC) is a chronic, cholestatic liver disease of unknown cause. In the study, we found that duck circovirus (DuCV) induces PSC in natural and reproductive cases. PSC in DuCV naturally infected ducks was investigated by PCR and histopathology. A model of PSC was developed in one-day old duck by infection of DuCV. Effects on serum levels of liver enzymes and histology were evaluated, and DuCV tropism for bile duct in liver was analyzed by immuohistochemistry. Pathology observation of natural or reproductive DuCV infected ducks showed that the lesion of liver were characterized by cholangiocytic injuries and progressive fibrous obliteration of the biliary tree associated with lymphocytes infiltration. ALT, AST, ALP, GGT, ALB, TBIL and TP were significantly increased in serum of DuCV infected ducks. DuCV showed higher tropism for epithelial cells of bile duct than other cells in PSC. [ABSTRACT FROM AUTHOR]

A hole-transporting layer is essential for effective operation of planar perovskite solar cells. Hole-transporting materials (HTMs) used so far are mainly based on organic semiconductors, which are usually expensive and relatively instable compared with inorganic materials. In this article, crystalline selenium (c-Se) prepared by thermal evaporation followed by annealing at low temperature was used as the hole-transporting layer for the planar perovskite solar cells in the device structure of fluorine-doped tin oxide (FTO)/SnO 2 /perovskite/selenium/Au. The device employing c-Se as HTM displayed enhanced long-term stability, keeping 80% of the original efficiency after 40 days in ambient environment. However, the power conversion efficiency of 8.3% remains low compared with the device based on spiroOMeTAD, which results from higher recombination in the c-Se device as determined by impedance spectroscopy. Thermal-evaporated selenium could be a low-cost and easy-fabrication HTM for efficient and stable perovskite solar cells after reducing the recombination in devices. [ABSTRACT FROM AUTHOR]

In this work we report the Na incorporation from Na-doped Mo (Mo-Na) back contact for kesterite Cu 2 ZnSnS 4 solar cells on flexible stainless steel substrates. It is demonstrated that Na can be effectively incorporated into CZTS by inserting Mo-Na layer at back contact. Direct contact of CZTS and Mo-Na layer leads to poor homogeneity and adhesion. The thickness of MoS 2 formed at the back contact depends on the presence of Na and whether Mo contacts with CZTS directly. Back contact configuration with a Mo capping layer on Mo-Na layer is found to be helpful to maintain the advantages of Mo back contact and control the thickness of MoS 2 interface. As a result, CZTS device fabricated on this configuration yields higher conversion efficiency of 6.2%. However, this efficiency is still far lower than that on traditional soda lime glass substrate which shows efficiency over 8%. The loss mechanism of device fabricated on stainless steel is investigated and analyzed according to the device performance and electrical parameters. [ABSTRACT FROM AUTHOR]

In this research, we present thermal evaporated MoO 3 layer as a primary back contact for pure sulphide Cu 2 ZnSnS 4 solar cells. The effects of incorporating MoO 3 in primary back contact and its thickness on the Cu 2 ZnSnS 4 device performance are investigated. The MoO 3 layer acts as enhancing sodium diffusion site where sodium is more effectively diffused into CZTS absorber, facilitating the formation of larger CZTS grains during sulfurization process compared to the reference absorber. The power conversion efficiency is improved from 5.2% to 6.2% on average, yielding the highest efficiency of 6.52% by the insertion of 10 nm MoO 3 layer between Cu 2 ZnSnS 4 absorber and molybdenum contact. The major efficiency enhancement arises from open circuit voltage which is improved from 530 to 615 mV. [ABSTRACT FROM AUTHOR]

Tandem technologies offer potential price reductions and higher efficiencies of PV modules. The high band gap nature of chalcogenides like CIGS, CZTS and AZTS makes them excellent materials for use on top of a Si base tandem cells. Nevertheless, along with the search for new technologies, there is also the concern about the environmental impact that its lifetime can cause. A comprehensive life cycle assessment for CIGS/Si, CZTS/Si and AZTS/Si tandem solar modules was not reported to date. This work compares the environmental impacts of Si and chalcogenide/Si tandem solar modules, assessing global warming potential, human toxicity potential (cancer and non-cancer effects), freshwater eutrophication potential, freshwater ecotoxicity potential, abiotic depletion potential and the energy payback time of these technologies. The results of this study show that compared with Si, CIGS/Si presents worse environmental impacts for most of the categories but, on the other hand, CZTS/Si and AZTS/Si present better outcomes for most of the impacts categories. We can also say that higher efficiency of these tandem technologies could potentially reverse that result. This LCA provides design advice for the R&D community, showing which structure has the best environmental outcomes and which processes should be optimized to achieve better results. [ABSTRACT FROM AUTHOR]