Doping Position Research Articles

Impact of strain and doping on Li-ion transport in Li3OBr0.5Cl0.5 anti-perovskite solid lithium-ion electrolytes: Insights from DFT and AIMD calculations

The impact of applying strain on the Li-ion transport characteristics of Li3OBr0.5Cl0.5 anti-perovskite solid lithium-ion electrolytes with different doping positions have been systematically studied within the framework of density functional theory. We have examined the changes in bandgap, defect formation energy, and Li-ion migration barrier under triaxial compressive and tensile strains, spanning from −4% to 4 %. Following, by calculating of the diffusion and conductivity of different structures of Li3OBr0.5Cl0.5, we have screened out one structure (Br-ions and Cl-ions are diagonally distributed at each vertex of the lattice) with the highest conductivity at room temperature from six structures of Li3OBr0.5Cl0.5. Afterward, the changes of diffusion, conductivity and MSD of the structure with the highest conductivity at room temperature under applying −4% and 4 % triaxial strains have been studied. The results reveal intriguing implications: Tensile strains increase the defect formation energy for both Li-ion vacancies and Li interstitials, while simultaneously lowering the migration barrier of Li-ion. The influences of the formation energy and migration barrier significantly enhance the conductivity of Li-ion. This consequence is confirmed by AIMD simulation that both diffusivity and conductivity are enhanced under applying tensile strains, while an opposing effect observed under applying compressive strains. These findings unequivocally demonstrate that strains exert a profound influence on Li-ion conductivities in Li3OBr0.5Cl0.5 anti-perovskite electrolytes. Specifically, the application of tensile strain emerges as a promising strategy to augment lithium-ion transport.

The effects of biaxial strain and sulfur/boron doping on the photocatalytic performance of the g-C3N5 system: A first-principles study

Strain and doping are effective methods for enhancing the intrinsic properties of the photocatalyst g- C3N5. This paper investigates the electronic properties, optical characteristics, and changes in Gibbs free energy of g-C3N5 under the combined effects of biaxial strain and sulfur/boron (S/B) doping through first-principles calculations. By calculating the formation energy of the doping system, the optimal doping positions for B/S are identified. The results indicate that intrinsic g-C3N5 exhibits indirect band gap semiconductor properties with a band gap of 1.851 eV. In contrast, S/B doping reduces the band gap, with the S-doped g-C3N5 system (S-g-C3N5) displaying direct band gap semiconductor properties and a band gap of 1.677 eV. The application of tensile or compressive strain induces a red shift or blue shift in the absorption spectra of both the intrinsic g-C3N5 system and the doped system. Tensile strain positions the band edges of all systems favorably, enhancing carrier mobility and redox capability. This study provides valuable insights for the development of photocatalytic carbon nitride through atomic doping and strain modulation.

Title : The Flexible Solar Cells Using Earth Abundant Materials

The development of flexible solar cells utilizing non-toxic, earth-abundant materials is of paramount importance in driving market competitiveness and fostering the adoption of innovative business models such as Building Integrated Photovoltaics. While CZTS-based (Cu2ZnSnS4, Cu2ZnSnSe4, Cu2ZnSn(S,Se)4) solar cells offer promising cost advantages due to their low-cost available absorber materials, their progress has been impeded by challenges like narrow phase stability and secondary phase defects.To address these challenges, researchers have been actively exploring the potential of metal-doping effects, employing elements such as Ag, Li, Na, K, and Rb to enhance the performance and stability of CZTS-based solar cells. Understanding the reaction mechanisms involved in dopant incorporation is crucial for optimizing fabrication processes and ultimately improving solar cell efficiency.In this study, CZTSSe solar cell devices were designed, comprising an Mo back contact, CZTSSe absorber, CdS buffer layer, ZnO layer, Al-doped ZnO layer, and an Al collection grid. The doping effects of Ag (applied on a rigid SLG substrate with Na impurity) and Na (applied on a flexible substrate without Na impurity) at different dopant layer positions of the Sn/Cu/Zn precursor structure were investigated.Without a dopant layer, the precursors revealed the formation of Cu-Zn and Cu-Sn alloys despite the deposition sequence of Zn, Cu, Sn at room temperature. Upon pre-annealing at 300 °C, the formation of the ZnSSe layer was observed from the Cu-Zn alloy, followed by the formation of Cu2Se and SnSe at temperatures exceeding 400 °C [1]. In the Sn/Cu/dopant layer/Zn precursor structure, the reaction pathways of CZTSSe were found to be influenced by the presence of dopant layers, which acted as barriers, blocking Zn and Cu/Sn diffusion, and altering the initial reaction mechanism during the annealing process.It was observed that the application of Sn/Cu/Zn/dopant layer or Sn/dopant layer/Cu/Zn precursor significantly enhanced the characteristics of the solar cell devices. By mitigating defect levels and reducing the Voc deficit, dopants led to an improvement in power conversion efficiency [2]. This enhancement can be attributed to the associated decrease in defects, which are considered recombination centers within the CZTSSe absorber layer and can be effectively passivated by dopants.Overall, the CZTSSe solar cells exhibited promising efficiencies of 12.6% and 12.3% on rigid and flexible substrates, respectively.[1] Kim, S.-Y., Son, D. H., Kim, Y. I., Kim, S. H., Kim, S. M., Ahn, K. S., Sung, S. J., Hwang, D. K., Yang, K. J., Kang, J. -K., Kim, D.-H., Nano Energy 59 (2019) 399-411[2] K.-J.Yang, S.Kim, S.-Y.Kim, D.-H.Son, J.Lee, Y.-I.Kim, S.-J.Sung, D.H.Kim, T.Enkhbat, J.H.Kim, J.Kim, W.Jo, J.-K. Kang, Advanced Functional Materials 31 (2021) 2102238Acknowledgment: This work was supported in part by the program of Phased development of carbon-neutral technologies (2022M3J1A1085371) through NRF (National Research Foundation of Korea) and in part by DGSIT R&D Program of the Ministry of Science and ICT of Korea (Grant numbers 23-ET-08 and 23-CoE-ET-01).

First-principles calculation of the effects of In doping on η-Cu6Sn5 structure, elastic anisotropy, electronic properties and fracture toughness

During the welding and service stages, the anisotropy of Cu6Sn5 between tin solder / Cu solder joints will lead to abnormal grain growth and fracture of Cu6Sn5, which will eventually lead to solder joint failure, so it is very important to study the alloying element indium (In) to reduce the anisotropy of Cu6Sn5. The effects of indium doping on the crystal structure, electronic structure and mechanical properties of η-Cu6Sn5 have been studied systematically by means of first-principles density functional theory. Through calculation, it is found that with the change of indium doping position, the crystal structure is slightly deformed, but remains stable. Indium doping changes the electronic structure of η-Cu6Sn5, and a new bonding peak is formed by the hybridization of Cu-d and In-s around −5.9 eV. In addition, indium doping can significantly increase the mechanical properties of η-Cu6Sn5, including elastic modulus and hardness. Indium significantly reduces the anisotropy of η-Cu6Sn5, and the anisotropy decreases by nearly 80 % at most. At the same time, the addition of indium can increase the fracture toughness of η-Cu6Sn5.

Laser-induced nucleation of urea through the control of Insoluble Impurity

The mechanism of non-photochemical laser-induced nucleation (NPLIN) was investigated through the crystallization of urea crystals in supersaturated (151%) aqueous solutions. To detect the role of impurities in NPLIN, the effect of filtration, doping and laser irradiation position on nucleation probability were studied, respectively. As particles larger than the filter pore size in the solution were almost removed by syringe filter with poly (ether sulfone) membrane, the NPLIN probability was evidently suppressed by filtration when the pore sizes of filter were used from 1 μm to 0.45 μm. The inhibition of NPLIN after filtration could be reversed to varying degrees by adding several kinds and concentrations of impurities into the filtered solution; as the solid particles were extra added, age after cooling for samples was no longer necessary. The increase in the NPLIN probability with the irradiation height decreases was observed when samples were irradiated at different vertical positions within the sample vial. The experimental results were analyzed with reference to the known mechanisms. As nucleation probability through NPLIN can be controlled by pore size of syringe filter, doping or laser irradiation position, several functions were established to analyze the nucleation probability distribution under the effect of these three factors. These experimental results were discussed with reference to the known mechanisms proposed for NPLIN.

The interstitial Ru dopant induces abundant Ni(Fe)[sbnd]Ru cooperative sites to promote ampere-level current density for overall water splitting

Directionally induced interstitial Ru dopant rather than ordinary substitutional doping is a challenge. Furthermore, DFT calculations revealed that compared with the substituted Ru dopants, the interstitial Ru dopants induce abundant Ni(Fe)Ru cooperative sites, greatly expediting the reaction kinetics for HER and OER. Inspired by these, the interstitial Ru-doped NiFeP/NF electrode is constructed by the ’quenching doped Ru-phosphorization’ strategy. Relevant physical characterizations confirmed that interstitial Ru dopants promote electron reset in the Ni(Fe)Ru synergistic sites, effectively avoiding metal atom dissolution and encouraging more Ni (Fe)OOH active species. As expected, the Ru-NiFeP/NF||Ru-NiFeP/NF electrolyzer only need as low as 1.54 V to yield a current density of 1 A cm−2. In summary, this work innovatively constructs the phosphide electrode with ampere-level current density from the perspective of regulating the doping position of Ru. This provides a new design idea for optimizing the Ru doping strategy.

Machine Learning-Enhanced Screening of Single-Atom Alloy Clusters for Nitrogen Reduction Reaction.

The electrochemical nitrogen reduction reaction (eNRR) under ambient conditions is a promising method to generate ammonia (NH3), a crucial precursor for fertilizers and chemicals, without carbon emissions. Single-atom alloy catalysts (SAACs) have reinvigorated catalytic processes due to their high activity, selectivity, and efficient use of active atoms. Here, we employed density functional theory (DFT) calculations integrated with machine learning (ML) to investigate dodecahedral nanocluster-based SAACs for analyzing structure-activity relationships in eNRR. Over 300 nanocluster-based SAACs were screened with all the transition metals as dopants to develop an ML model predicting stability and catalytic performance. Facet sites were identified as optimal doping positions, particularly with late group transition metals showing superior stability and activity. Utilizing DFT+ML, we identified 8 highly suitable SAACs for eNRR. Interestingly, the number of valence d-electrons in dopants proved crucial in screening for eNRR activity. These catalysts exhibited low activity in hydrogen evolution reaction, further enhancing their suitability for eNRR. This successful ML-driven approach accelerates catalyst design and discovery, holding significant practical implications.

First principles insights into the electronic and magnetic properties of [formula omitted] doped with VIII-group transition metal single atom

Inspired by the unprecedented surface chemical reaction activity of single-atom catalysts (SAC), this research presents a theoretical study on the doping of SnO2(110) surface with transition metal group VIII atoms (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt). Using density functional theory (DFT), the formation energy, electronic structure, charge transfer and magnetic moments of the SnO2(110) system before and after doping were investigated. The formation energies of the different doped systems vary depending on the doping position. The doping of transition metal (TM) atoms can induce produces both charge transfer and magnetic moment. The charge transfer is largest in the Pd-doped system, with + 0.68 e at the position of the penta-coordinated Sn atom (Sn5c position) and + 0.67 e at the position of the hexa-coordinated Sn atom (Sn6c position), while the Co-doped system exhibits the smallest charge transfer of + 0.19 e (Sn6c position). Fe, Co, Ni, Ru and Os atoms introduce magnetic moments, with the Fe-doped system (Sn5c position) having the highest magnetic moments of 2.91 μB. In the SnO2(110) surface system doped with TM atoms, there are varying degrees of orbital overlap between the TM atoms and their surrounding O atoms. This theoretical work provides valuable insights into the physical properties of metal oxide based single-atom catalysts.

Important structural parameter for curvature effect of TM-N4 embeded C70 fullerenes as electrocatalysts for CO2 reduction interpreted with machine learning and first-principles calculations

In this work, TM-N4 sites embedded on curved C70 Fullerenes (TMN4(n)@C64, n = 1–5 which denote the doping positions and TM = Sc-Zn) were designed as efficient catalysts for electrochemical CO2 reduction reaction (ECO2RR). With interpretable machine learning (ML) and first-principles calculations, the performance of TM-N4 sites as possible electrocatalysts for ECO2RR under the curvature effect were revealed. After the screen procedure of catalyst stability, CO2 activation and selectivity of 50 designed systems, VN4(3), CrN4(3), MnN4(2), FeN4(2, 3, 5)@C64 were identified as high performance catalysts for ECO2RR to CH4, with limiting potential of -0.41 V, -0.26 V, -0.28 V, -0.35 V, -0.25 V and -0.17 V respectively, outperform the TM-N4 catalysts on the flat surface. A key structural descriptor K which can reflect the curvature effect of TM-N4 sites on the curved surface was identified with ML models. The gradient boosting regression (GBR) and sure independence screening and sparsifying operator (SISSO) algorithm reveal that the structural parameter K have strong association with the CO2 adsorption and significant influence on the selectivity of catalysts. Interestingly, the structural parameter K can influence more the binding of O-bonded intermediates than C-bonded intermediates. With the GBR algorithm, an effective model for the prediction of the limiting potential for C1 products were obtained. This study clarified the curvature effect of TM-N4 supported on the curved surface, and provides valuable guidance for the designing of TM-N4 single atom catalysts for ECO2RR on curved surface.

Optical and electronic properties of RENiO3 doped with alkali earth metals (Be, Mg, Ca, Sr and Ba): Combining first principles calculations and machine learning

The perovskite rare earth nickelate (RENiO3) has attracted significant attention owing to its peculiar physical properties and promising potential for diverse applications. It is reported that introducing H or Li might change the electronic and optical properties of RENiO3. However, little is known about multi-electrons doping in RENiO3. In this study, the bandgaps, optical and electronic properties were investigated in RENiO3 with alkaline earth metal (AEM) elements (Be, Mg, Ca, Sr and Ba) doping. For the atomic configurations of doped RENiO3, the interstitial sites of RENiO3 are more likely to be occupied by Be, Mg and Ca atoms, whereas Sr and Ba atoms tend to replace RE atoms in RENiO3. The band gap of RENiO3 decreases after AEM doping. Moreover, the machine learning results found that the formation energy of the AEM, the relative atomic mass of the AEM, and the doping position significantly influence the band gap. Furthermore, the infrared light blocking capability, the visible light transmission, and the electronic conductivity are enhanced in AEM doped RENiO3. This study may contribute to the experimental modulation of the optical and electronic properties of RENiO3 through AEM doping.

Prospect for detecting magnetism in two-dimensional perovskite oxides by electron magnetic circular dichroism

Two-dimensional (2D) magnets, especially strongly correlated 2D transition-metal perovskite oxides, have attracted significant attention due to their intriguing electromagnetic properties for potential applications in spintronic devices. Potentially electron magnetic circular dichroism (EMCD) under zone axis conditions can provide three-dimensional components of magnetic moments in 2D materials, but the collection efficiency and the signal-to-noise ratio for out-of-plane (OOP) components is limited due to the limited collection angle. Here we conducted a comprehensive computational simulation to optimize the experimental setting of EMCD for detecting the OOP components of magnetic moments in three beam conditions (3BCs) on 2D perovskite oxides La1-xSrxMnO3 (LSMO) in a TEM. The key parameters are sample thickness, accelerating voltage, Sr doping concentration, collection semi-angle and position, and sample orientation including systematic reflections excited and tilt angle. Our simulation results demonstrate that the relative dynamical diffraction coefficients of Mn OOP EMCD of LaMnO3 with a thickness ranging from 1 unit cell (uc) to 4 uc can be optimized in a 3BC with (110) systematic reflections excited and a relatively large collection semi-angle of 19 mrad at the relatively low accelerating voltage of 80 kV. In most cases, the relative dynamic diffraction coefficients for La1-xSrxMnO3 with the thickness ranging from 1 uc to 4 uc decrease with the increase of the Sr doping concentrations. The optimal tilt angle from a zone axis to a 3BC is 18° for the cases of the LSMO thickness of 2 uc, 3 uc and 4 uc, and 22° for the monolayer LSMO. Our work provides the theoretical simulation foundation for optimized EMCD experiments for measuring OOP components of magnetic moments in 2D transition-metal perovskite oxides.

Implications for electronic structures of S-doped graphene nanoribbons from a DFTB algorithm at atomic scale

Self-consistent charge density functional tight binding simulations were used to provide implications for the effect of S atoms’ doping on geometrical structures and electronic states in armchair graphene nanoribbons with different widths. The geometric configurations, energy, charge density differences, Mulliken charges, and molecular orbitals at HOMO and LUMO energy levels are characterized. Besides the changes of bond length and bond angles, the calculation results indicate that the band structures and bandgaps of the graphene nanoribbons is affected by the nanoribbon width as well as S doping positions, where the ribbons exhibit metallic or semiconductor properties. Doping S atoms result significant changes in the charge density differences and Mulliken charges on the atoms near the doped atom. At the same time, the HOMOs and LUMOs also present differences.

One-pot synthesis and chiroptical activity of single Au-atom doped AuAg28 clusters protected by water-soluble chiral monothiol N‑acetyl‑(S)‑penicillamine (S-NAP)

Physicochemical properties of atomically precise metal clusters can be modulated by incorporating different metal atoms. In this article, successful one-pot synthesis of single Au-atom doped chiral AuAg28 clusters protected by water-soluble N‑acetyl‑(S)‑penicillamine (=S-NAP) is reported. The reduction of Ag and Au ions at 0 °C in the presence of S-NAP and triphenylphosphine (TPP) using tetramethylammonium borohydride (TMAB) is crucial. Importantly, upon doping of an Au atom to the monometallic Ag29 cluster, which improves the cluster stability, the chiroptical activity or maximum anisotropy factor of the bimetallic AuAg28 cluster is enhanced as compared to that of the monometallic species, which can be due to an increase in the rotatory strength that is probably brought about by the increased contribution of optical transition associated with helically-arranged surface shell layers. Such chiroptical behaviors suggest that the Au dopant position in the bimetallic cluster is not fluxional but rigid. Then the present results will help design some heteroatom-doped silver clusters with excellent chiroptical properties.

DFT study of Cun (n = 1–3) cluster-modified WSe2 monolayers for the detection of SF6 decomposition gases (H2S, SO2, SOF2 and SO2F2)

The role of SF6 in gas-insulated equipment is crucial for insulation and arc extinction. When subjected to electrical faults, thermal faults, and mechanical failures in insulation devices, SF6 can decompose into H2S, SO2, SOF2, and SO2F2. This study conducted first-principles simulations to analyze the effect of Cun (n = 1–3) cluster-modified monolayer WSe2 on sensing H2S, SO2, SOF2, and SO2F2 gases during SF6 decomposition. The optimal doping positions of Cun-WSe2 clusters at n = 1, 2, and 3 were determined, showcasing their superiority over pure WSe2 in terms of band gap, frontier orbitals, and density of states. Subsequently, a detailed investigation was carried out on the adsorption effects of the four gases at the optimal doping positions, including parameters such as adsorption distance, adsorption energy, charge transfer, differential charge density, and density of states. It was found that when the number of copper atoms in the cluster increased to 3, the banding energy sharply rose to -2.395 eV. Simulation results demonstrated the adsorption behavior of H2S on Cun (n = 1–3)-WSe2 demonstrates remarkable affinity, with an increasing adsorption energy as the number of Cu atoms rises. Notably, Cun (n = 1–3)-WSe2 exhibits favorable desorption times for SO2. At 378 K, the desorption time for SO2@Cu3-WSe2 is 14.7 s. At 498 K, desorption times for SO2@Cu1-WSe2 and SO2@Cu2-WSe2 are 7.59 s and 2.85 s, respectively. When the number of copper atoms is 2, the cluster-modified system desorbs SOF2 at room temperature in only 0.89 s. Moreover, Cun (n = 1–3)-WSe2 displays strong adsorption towards SO2F2, characterized by prolonged desorption times, rendering it a promising adsorbent for SO2F2 removal. This study aims to highlight the adsorption effects of different numbers of Cu atomic clusters in the Cun-WSe2 system on SF6 decomposition gas, further advancing research for developing high-performance SF6 decomposition gas sensors.

Challenges to extracting spatial information about double P dopants in Si from STM images

The design and implementation of dopant-based silicon nanoscale devices rely heavily on knowing precisely the locations of phosphorous dopants in their host crystal. One potential solution combines scanning tunneling microscopy (STM) imaging with atomistic tight-binding simulations to reverse-engineer dopant coordinates. This work shows that such an approach may not be straightforwardly extended to double-dopant systems. We find that the ground (quasi-molecular) state of a pair of coupled phosphorous dopants often cannot be fully explained by the linear combination of single-dopant ground states. Although the contributions from excited single-dopant states are relatively small, they can lead to ambiguity in determining individual dopant positions from a multi-dopant STM image. To overcome that, we exploit knowledge about dopant-pair wave functions and propose a simple yet effective scheme for finding double-dopant positions based on STM images.

Data-driven deep learning prediction of boron-doped graphene work function

The atomic-scale doping plays a crucial role in determining the work function of doped graphene. However, it is a challenge to comprehensively investigate its work function due to the large range of possible molecular configurations. In this study, more than 30,000 pieces of data of the work functions from boron-doped graphene with different doping concentrations and positions is calculated via DFT, and the dataset is further expanded to 115,000 based on the molecular structural symmetry. Then, a simple structural descriptor-based method is developed to characterize the surface of the doped graphene. Finally, a deep learning model is proposed to predict the work function. The results show that the proposed model can accurately predict the work function with the R2 > 0.95 and MSE < 0.0013 for a 3×3 supercell. In addition, this study also provides the possibility to quickly investigate the work function of other heteroatom 2D materials.

Harnessing BN co-doping for superior thermal transport in phagraphene monolayer

In this study, we thoroughly explored the thermal transport and thermoelectric properties of BN-co-doped phagraphene structures in the context of first-principles computations combined with machine learning interatomic potential (MLIP) techniques. Our results demonstrate that doping positions can critically tune the thermal properties, offering potential advantages for both thermoelectric and heat transfer applications. Notably, enhanced thermal conductivity has been obtained for phagraphene with 10 % co-doping. Additionally, the rectangular structural symmetry of phagraphene plays an important role for targeted thermal transport. Further, we observe negative Grüneisen parameter in these structures, suggesting negative thermal expansion. This will serves as an unique mechanism for controlling the thermal conductivity at different frequencies. Interestingly, n-type behavior of the structures is indicative of its negative Seebeck coefficient within the temperature range of 300–900 K. Moreover, these structures display significantly larger electrical conductivity compared to other two-dimensional (2D) materials. Apart from that, the calculated figure of merit of the structures under a constant relaxation time at 300 K shows considerably better response for some specific doped structures. We believe this study will play an important role in understanding the importance of structural modifications in tailoring the thermal properties of carbon-based 2D systems.

Surface reconstructed layer with bulk high-valence Mo doping to achieve long-life LiMn2O4 cathode material

Mo doping plays a striking role in the stability enhancement of LiMn2O4 cathode materials. However, the underlying microscopic mechanism is still unclear. Here, we elucidate that the relationship between the atomic position of Mo doping in LiMn2O4 and the stability enhancement of Mo-doped LiMn2O4 by utilizing the spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM). It exhibits that the part of Mo6+ ions occupy empty Mn 16c site to form a surface reconstructed layer of rock-salt like phase on the outermost surface and other Mo6+ ions dope into the Mn octahedral 16d sites to form LiMoxMn2-xO4 in bulk, which is beneficial for inhibiting the parasitic side reactions. Concomitantly, this dual modification of bulk structure and surface can significantly enhance electrode reversibility and Li+ diffusion. As a result, excellent long cycling stability of the as-designed optimal LiMo0.01Mn1.99O4 after 1500 cycles with 61.61 % capacity retention at 10 C (1 C = 148 mAh g−1) is presented, with an initial discharge capacity of 88.30 mAh g−1. Our research provides a clever approach for regulating the surface structure/bulk architecture in LiMn2O4 cathode materials.

Anchored MoS2 co-catalysts on ZnxCd1-xS solid solution for photocatalytic reduction of U(VI)

In recent years, a great deal of attention has focused on achieving higher photocatalytic performance by modifications. However, external modification methods, such as heterojunction, defect engineering and doping, bring the disadvantage of mismatch of energy band positions or uncontrollable defects and doping positions, resulting in different photocatalytic efficiencies for different batches of materials. As a result, the search for new modification methods is currently the focus of photocatalytic reduction of U(VI). In this work, the modification method of forming a solid solution between Zn, Cd and S by adjusting the ratio of Zn /Cd precursors, i.e., the internal modification method, is proposed to solve the problem of matching the energy band structure, keeping the conduction band in the right position and facilitating efficient charge separation, and complexing with MoS2 co-catalysts to improve the catalytic performance of the catalyst. A novel complex, MoS2/Zn0.2Cd0.8S, has been designed and synthesized. And the photocatalytic reduction of U(VI) by Zn0.2Cd0.8S was 27 and 373 times higher than that of pure CdS and ZnS, respectively, and MoS2/Zn0.2Cd0.8S was 24.45 % higher than that of Zn0.2Cd0.8S (74.75 %), with a reduction rate of 99.20 % under 60 min of illumination. Gladly, its photocatalytic activity remained above 95.67 % after five cycles, and there was no difference in the performance of catalysts synthesised in different batches, showing excellent stability and reproducibility. Moreover, the mechanism of U(VI) reduction was investigated by MoS2/Zn0.2Cd0.8S. This study provides a new strategy to guarantee the preparation of photocatalysis with stable performance and improve photocatalytic performance.

Effects of Zn contents and doping positions on the mechanical properties of η′-Cu6Sn5

η′-Cu6Sn5 is one of the main components of intermetallic compounds in the solder joint of electronic components. The research on improving its performance will help to solve the problem of increasing mechanical properties, electrical conductivity and thermal conductivity of solder joints of electronic devices. In this paper, we use the first-principles method to calculate the effects of 0.57 at.% and 1.14 at.% Zn doped on the Cu1, Cu2, Cu3 and Cu4 positions of η′-Cu6Sn5 on the mechanical and electronic properties of the structure. And we draw a 3D model to express the mechanical anisotropy of the doping system. The calculated results show that doping Zn makes η′-Cu6Sn5 more stable. However, the addition of Zn also reduces the fracture toughness of η′-Cu6Sn5, increases the anisotropy of η′-Cu6Sn5, and weakens the shear resistance of the solder joint of electronic devices.