An official website of the United States government
Direct arylation is an appealing method for preparing π-conjugated materials, avoiding the prefunctionalization required for traditional cross-coupling methods. A major effort in organic electronic materials development is improving the environmental and economic impact of production; direct arylation polymerization (DArP) is an effective method to achieve these goals. Room-temperature polymerization would further improve the cost and energy efficiencies required to prepare these materials. Reported herein is new mechanistic work studying the underlying mechanism of room temperature direct arylation between iodobenzene and indole. Results indicate that room-temperature, Pd/Ag-catalyzed direct arylation systems are radical-mediated. This is in contrast to the commonly proposed two-electron mechanisms for direct arylation and appears to extend to other substrates such as benzo[ b ]thiophene and pentafluorobenzene.
more »
« less
Towards Green Synthesis and Processing of Organic Solar Cells
Abstract In 2018, several major breakthroughs have been achieved in organic solar cells (OSCs) with the record power conversion efficiency (PCE) reaching over 17 %. With this increased efficiency, it is time to take a step forward to consider how to convert this technology into large scale production. For this, the economic and environmental profile of OSCs should be taken seriously‐simplified synthetic routes and green chemistry methods should be applied. According to previous studies, OSCs are competitive and profitable in the commercial market. However, toxic and/or hazardous chemicals are currently used in materials synthesis and device fabrication of OSCs. In this account, we will talk about contributions and efforts we have made to minimize the economic and environmental disadvantages in the production of OSCs. We will start with the background on how our projects were conceived and will specifically discuss our work on direct arylation and green solvent. Developments of direct arylation for synthesizing conjugated polymers will be illustrated along with our recent finding regarding the effect of green solvents on device performance and stability.
more »
« less
- Award ID(s):
- 1700982
- PAR ID:
- 10083383
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- The Chemical Record
- Volume:
- 19
- Issue:
- 6
- ISSN:
- 1527-8999
- Page Range / eLocation ID:
- p. 1039-1049
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Ross, H (Ed.)Abstract This study offers an updated bioeconomy perspective on biobased routes to high‐purity silicon and silica in the context of the societal, economic and environmental trends reshaping chemical processes. We summarize the main aspects of the green chemistry technologies capable of transforming current production methods. Coincidentally, we discuss selected industrial and economic aspects. Finally, we offer perspectives of how said technologies could/will reshape current chemical and energy production.more » « less
-
Greenhouses conserve land and water while increasing crop production, making them an attractive system for low environmental impact agriculture. Yet, to achieve this goal, there is a need to reduce their large energy demand. Employing semitransparent organic solar cells (OSCs) on greenhouse structures provide an opportunity to offset the greenhouse energy needs while maintaining the lighting needs of the plants. However, the design trade-off involved in optimizing solar power generation and crop productivity to maximize greenhouse economic value is yet to be studied in detail. Here, a functional plant growth model is integrated with a dynamic energy model that includes supplemental lighting to optimize the economics of growing lettuce and tomato. The greenhouse optimization considers 64 different OSC active layers with varying roof coverage for 25 distinct climates providing a global perspective. We find that crop yield is the primary economic driver, and that crop yield can be maintained in OSC-greenhouses across diverse climates. The crop productivity along with the energy produced by the OSCs results in improved net present value of the OSC-greenhouses relative to conventional systems in most climates for both lettuce and tomato. In addition, we find common solar cell active layers that maximize greenhouse economic value resulting in guidelines for scaling up OSC-greenhouse design. Through this model framework, we highlight the opportunity for OSCs in greenhouses, uncover designs and locations that provide the most value, and provide a basis for further development of OSC-greenhouses to achieve a sustainable means of food production.more » « less
-
We report sequential ruthenium(0)-catalysis for the synthesis of sterically-hindered amines via direct C–H arylation of simple imines and imine hydrosilylation. The method involves direct C–H arylation under neutral conditions with organoboranes enabled by ruthenium(0) catalysis. The catalytic hydrosilylation was performed in a one-pot fashion using Et 3 SiH. The reaction is compatible with a broad range of electronically- and sterically-varied imines, enabling rapid production of valuable biaryl amines in good to excellent yields. The method constitutes a two-step, one-pot procedure to synthesize sterically-hindered amines from aldehydes. The utility of this atom-economic strategy is demonstrated in one-pot, three-component coupling, direct in situ aldehyde arylation and the use of transfer hydrogenation.more » « less
-
Abstract The commercialization of nonfullerene organic solar cells (OSCs) critically relies on the response under typical operating conditions (for instance, temperature and humidity) and the ability of scale‐up. Despite the rapid increase in power conversion efficiency (PCE) of spin‐coated devices fabricated in a protective atmosphere, the efficiencies of printed nonfullerene OSC devices by blade coating are still lower than 6%. This slow progress significantly limits the practical printing of high‐performance nonfullerene OSCs. Here, a new and relatively stable nonfullerene combination is introduced by pairing the nonfluorinated acceptor IT‐M with the polymeric donor FTAZ. Over 12% efficiency can be achieved in spin‐coated FTAZ:IT‐M devices using a single halogen‐free solvent. More importantly, chlorine‐free, blade coating of FTAZ:IT‐M in air is able to yield a PCE of nearly 11% despite a humidity of ≈50%. X‐ray scattering results reveal that large π–π coherence length, high degree of face‐on orientation with respect to the substrate, and small domain spacing of ≈20 nm are closely correlated with such high device performance. The material system and approach yield the highest reported performance for nonfullerene OSC devices by a coating technique approximating scalable fabrication methods and hold great promise for the development of low‐cost, low‐toxicity, and high‐efficiency OSCs by high‐throughput production.more » « less
