Synthesis cost dictates the commercial viability of lead sulfide and perovskite quantum dot photovoltaics

Any new solar photovoltaic (PV) technology must reach low production costs to compete with today’s market- leading crystalline silicon and commercial thin-film PV technologies. Colloidal quantum dots (QDs) could open up new applications by enabling lightweight and flexible PV modules. However, the cost of synthesizing nanocrystals at the large scale needed for PV module production has not previously been investigated. Based on our experience with commercial QD scale-up, we de velop a Monte Carlo model to analyze the cost of synthesizing lead sulfide and metal halide perovskite Q Ds using 8 different reported synthetic methods. We also analyze the cost of solution-phase ligand exchange for p reparing deposition-ready PbS QD inks, as well as the manufacturing cost for roll-to-roll solution-processe d PV modules using these materials. We find that present QD synthesis costs are prohibitively high for PV applications, with median costs of 11 to 59 $per g for PbS QDs (0.15 to 0.84$ per W for a 20% efficient cell) and 73 $per g for CsPbI₃ QDs (0.74$ per W). QD ink preparation adds 6.3 $per g (0.09$ per W). In total, QD materials contribute up to 55% of the total module cost, making even roll-to-roll-processed QDPV modules significantl y more expensive than silicon PV modules. These results suggest that the development of new lo w-cost synthetic methods is critically important for the commercial relevance of QD photovoltaics. Using our cost model, we identify strategies for reducing synthetic cost and propose a cost target of 5 $ per g to move QD solar cells closer to commercial viabilityTata Trust

High-Speed Vapor Transport Deposition of Perovskite Thin Films

Intensive research of hybrid metal-halide perovskite materials for use as photoactive materials has resulted in an unmatched increase in the power conversion efficiency of perovskite photovoltaics (PVs) over the last couple of years. Now that lab-fabricated perovskite devices rival the efficiency of silicon PVs, the next challenge of scalable mass manufacturing of large perovskite PV panels remains to be solved. For that purpose, it is still unclear which manufacturing method will provide the lowest processing cost and highest quality solar cells. Vapor deposition has been proven to work well for perovskites as a controllable and repeatable thin-film deposition technique but with processing speeds currently too slow to adequately lower the production costs. Addressing this challenge, in the present work, we demonstrate a high-speed vapor transport processing technique in a custom-built reactor that produces high-quality perovskite films with unprecedented deposition speed exceeding 1 nm/s, over 10× faster than previous vapor deposition demonstrations. We show that the semiconducting perovskite films produced with this method have excellent crystallinity and optoelectronic properties with 10 ns charge carrier lifetime, enabling us to fabricate the first photovoltaic devices made by perovskite vapor transport deposition. Our experiments are guided by computational fluid dynamics simulations that also predict that this technique could lead to deposition rates on the order of micrometers per second. This, in turn, could enable cost-effective scalable manufacturing of the perovskite-based solar technologies. Keywords: solar cells; perovskite; thin-film; vapor deposition; manufacturing; fluid dynamicsNational Science Foundation (U.S.) (Award 1541959)National Science Foundation (U.S.) (Grant 1605406

A review of nitrogen use efficiency in sugarcane

The review identified three key findings that can be summarised as (i) A need for an improved framework for both researching and benchmarking NUE; (ii) Identification of promising opportunities for improving NUE through targeted R and D. These were likely to include aspects relating to improved decision support systems and diagnostics to define the appropriate N rate, improved fertilizer technology and management, and improved crop genetics delivering improved recovery and use of applied N; and (iii) Maintaining a focus on extension, communication and industry engagemen

REVIEW: SOLUTIONS FOR GRAND CHALLENGES IN GOAT AND SHEEP PRODUCTION INDUSTRY

Goats and sheep are valuable as they are a source of meat, milk, fleece, and other products. These livestock are also important both for agriculture and biomedical research. However, the efficient, sustainable, and profitable production of these small ruminants faces major obstacles. Hence, this review analyzes these major challenges specifically, their negative impacts on the industry, and suggests some science-based solutions to overcome them. Those challenged areas are education and training, research, translational research/biotechnology, goat and sheep health, and maintenance of an economically sustainable agribusiness. The suggested solutions include the effective teaching of goat and sheep science to the next generation and public empowerment, support for innovative and translational research, disease prevention and treatment, support for technology transfer, and development of sound agribusiness practices. This review is helpful particularly for scientists, students, and the goat and sheep producers. In general, these information on the current state of goat and sheep agriculture will also help the public to better understand and appreciate the challenges met and opportunities provided in small ruminant production enterprises

2022 taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales

In March 2022, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by two new families (bunyaviral Discoviridae and Tulasviridae), 41 new genera, and 98 new species. Three hundred forty-nine species were renamed and/or moved. The accidentally misspelled names of seven species were corrected. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV

2022 taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

In March 2022, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. The phylum was expanded by two new families (bunyaviral Discoviridae and Tulasviridae), 41 new genera, and 98 new species. Three hundred forty-nine species were renamed and/or moved. The accidentally misspelled names of seven species were corrected. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV