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1. Large-Scale Synthesis of Semiconducting Cu(In,Ga)Se2 Nanoparticles for Screen Printing Application

   https://doi.org/10.3390/nano11051148  

   Gonçalves, Bruna F.; LaGrow, Alec P.; Pyrlin, Sergey; Owens-Baird, Bryan; Botelho, Gabriela; Marques, Luis S.; Ramos, Marta M.; Kovnir, Kirill; Lanceros-Mendez, Senentxu; Kolen’ko, Yury V. (May 2021, Nanomaterials)

   null (Ed.)

   During the last few decades, the interest over chalcopyrite and related photovoltaics has been growing due the outstanding structural and electrical properties of the thin-film Cu(In,Ga)Se2 photoabsorber. More recently, thin film deposition through solution processing has gained increasing attention from the industry, due to the potential low-cost and high-throughput production. To this end, the elimination of the selenization procedure in the synthesis of Cu(In,Ga)Se2 nanoparticles with following dispersion into ink formulations for printing/coating deposition processes are of high relevance. However, most of the reported syntheses procedures give access to tetragonal chalcopyrite Cu(In,Ga)Se2 nanoparticles, whereas methods to obtain other structures are scarce. Herein, we report a large-scale synthesis of high-quality Cu(In,Ga)Se2 nanoparticles with wurtzite hexagonal structure, with sizes of 10–70 nm, wide absorption in visible to near-infrared regions, and [Cu]/[In + Ga] ≈ 0.8 and [Ga]/[Ga + In] ≈ 0.3 metal ratios. The inclusion of the synthesized NPs into a water-based ink formulation for screen printing deposition results in thin films with homogenous thickness of ≈4.5 µm, paving the way towards environmentally friendly roll-to-roll production of photovoltaic systems. 

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2. Green synthesis of CdS/Ni _x S _y nanoparticles as a route towards sustainable and scalable photocatalysts

   https://doi.org/10.1039/D2GC03361E  

   Sakizadeh, John; Cline, Joseph P.; Wolfe, Eva; Thorpe, Ryan; Snyder, Mark A.; Kiely, Christopher J.; McIntosh, Steven (October 2022, Green Chemistry)

   If hydrogen evolution photocatalysis are to be deployed at industrial scale, the synthesis of these photocatalytic materials must be both economically and environmentally scalable. This suggests that we must move towards green synthesis of earth-abundant photocatalysts while also maintaining high catalytic performance. Herein, we present the enzymatically driven, aqueous phase, low temperature, synthesis of an earth-abundant nickel sulfide (Ni x S y ) hydrogen evolution cocatalyst, and its integration into a CdS/Ni x S y heterostructured photocatalyst. This resulting photocatalyst provides hydrogen evolution rates (10 500 μmol h −1 g −1 ) comparable to photocatalysts prepared by more traditional routes. Furthermore, the Ni x S y is demonstrated to provide similar activity enhancement to the more traditional, but also more expensive platinum cocatalysts. To achieve this result, we carefully studied and engineered the synthesis environment to maintain enzyme activity towards HS − production while sustaining a sufficient concentration of free Ni 2+ in solution to enable reaction and formation of Ni x S y . Ultimately, this work provides a methodology to control the coordination of metal precursors in low temperature, aqueous systems to allow for precipitation of catalytically active materials and demonstrates the viability of green synthesis pathways for photocatalysts. 

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3. Cost analysis of thin film tandem solar cells using real world energy yield modelling

   https://doi.org/10.1109/PVSC40753.2019.8980734  

   Ahangharnejhad, Ramez Hosseinian; Phillips, Adam B; Celik, Ilke; Song, Zhaoning; Yan, Yanfa; Heben, Michael J (June 2019, 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC))

   Tandem photovoltaic (PV) cells with higher efficiency limits than current market dominated crystalline silicon PV devices are poised to be the next generation of solar cells. In this study we focus on analysis of perovskite/Cu(In x Ga 1-x )Se 2 tandem solar cells in the context of real-world conditions. Using material properties and the most recently updated atmospheric data we simulate the device energy yield for locations with different climate conditions. We use the resultant data in calculating module levelized cost and analyze the conditions under which using different forms of tracking become the cost-effective approach at each location. 

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4. Mixing of Spherical Solid and Nanoporous Copper Powders As Low-Reflectance Feedstock for Laser Powder Bed Fusion

   https://doi.org/10.1115/MSEC2023-105092  

   Kublik, Natalya; Niauzorau, Stanislau; Azeredo, Bruno (June 2023, ASME 2023 18th International Manufacturing Science and Engineering Conference)

   Abstract Micro- and nanoporous materials have gathered attention from the scientific community due to their size dependent properties, including but not limited to high specific surface area, surface diffusivity, bulk diffusivity and permeability, catalytic activity, and distinct optical properties. In this work, spherical nanoporous copper (np-Cu) powders, due to their nanosized porosity and low Cu2O content, show hemispherical total reflectance of 20% which is significantly lower than its bulk counterpart value for solid or molten copper of approximately 97% at wavelengths of most commercial Laser Powder Bed Fusion (L-PBF) commercial machines. The low-reflectance of np-Cu powders has the potential to be used in L-PBF to improve laser absorption, volumetric energy efficiency, and throughput of this additive manufacturing process. In fact, a prepared mixture of solid Cu powders containing only 5 wt.% of np-Cu powders reflects 34.8 % less than pure copper powders as shown in this paper. Np-Cu powders are fabricated via chemical dealloying of gas atomized CuAl alloy in a robust and scalable approach, and then mixed with pure copper powders to prepare hybrid feedstocks. Under this framework, the crucial role of deglomeration strategies to achieve homogeneity and flowability of np-Cu/Cu hybrid mixtures are evaluated via particle imaging to determine agglomerate size and composition with an eye at obtaining a high-quality print in L-PBF. In np-Cu powders fabrication, washing them in low-surface tension fluids upholds the highest degree of deglomeration in their fabrication process, and for hybrid feedstocks preparation, pre-mixing Cu and CuAl prior to dealloying yields the best homogeneity results with smallest size of agglomerates and good flowability. 

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5. High‐Performance Ammonia Electrosynthesis from Nitrate in a NaOH−KOH−H ₂ O Ternary Electrolyte

   https://doi.org/10.1002/anie.202403633  

   Shahid, Usman_Bin; Kwon, Yongjun; Yuan, Yuan; Gu, Shuang; Shao, Minhua (April 2024, Angewandte Chemie International Edition)

   Abstract A glut of dinitrogen‐derived ammonia (NH₃) over the past century has resulted in a heavily imbalanced nitrogen cycle and consequently, the large‐scale accumulation of reactive nitrogen such as nitrates in our ecosystems has led to detrimental environmental issues. Electrocatalytic upcycling of waste nitrogen back into NH₃holds promise in mitigating these environmental impacts and reducing reliance on the energy‐intensive Haber–Bosch process. Herein, we report a high‐performance electrolyzer using an ultrahigh alkalinity electrolyte, NaOH−KOH−H₂O, for low‐cost NH₃electrosynthesis. At 3,000 mA/cm², the device with a Fe−Cu−Ni ternary catalyst achieves an unprecedented faradaic efficiency (FE) of 92.5±1.5 % under a low cell voltage of 3.83 V; whereas at 1,000 mA/cm², an FE of 96.5±4.8 % under a cell voltage of only 2.40 V was achieved. Techno‐economic analysis revealed that our device cuts the levelized cost of ammonia electrosynthesis by ~40 % ($30.68 for Fe−Cu−Ni vs. $48.53 for Ni foam per kmol‐NH₃). The NaOH−KOH−H₂O electrolyte together with the Fe−Cu−Ni ternary catalyst can enable the high‐throughput nitrate‐to‐ammonia applications for affordable and scalable real‐world wastewater treatments. 

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