Electrically conducting oligo(pyrazoles)
Inventors
Martin, Brett D. • Trammell, Scott A. • Deschamps, Jeffrey R. • Naciri, Jawad • DePriest, Jeffrey C.
Assignees
Publication Number
US-11028053-B2
Publication Date
2021-06-08
Expiration Date
2034-05-16
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Abstract
An electrically conducting organic oligomer made from the steps of preparing an acidic aqueous solution with a monomer; preparing the acidic aqueous solution by mixing a solution of about 1.6 wt % HCl in DI water with a monomer; forming about a 0.3 M solution preparing a second aqueous solution with a sodium persulfate oxidant; mixing the acidic aqueous solution with the second aqueous solution; and allowing a reaction to proceed at about 40° C.
Core Innovation
This disclosure concerns two novel electrically conducting organic oligomers: oligo(3-amino-1H-pyrazole-4-carbonitrile) or “oligo(AP-CN)” and oligo(4-nitro-1H-pyrazole-3-yl-amine) or “oligo(AP-NO2)”. These oligomers have highly variable redox states and exhibit good electron-transporting properties. They are easy to synthesize, requiring only one step plus purification, and use inexpensive starting materials.
The development of these novel electrically conducting organic oligomers addresses the challenge in conducting polymer photovoltaics wherein low photon-to-current conversion efficiencies and short lifetimes limit performance. Conventional silicon-based solar cells are expensive to manufacture due to high temperature and vacuum processing conditions, while prior art polymer solar cells have relatively low efficiencies. Most conducting polymers are only p-dopable (stable carriers of positive charge), limiting applications as electron transporters. Conducting polymers that are stable in their n-doped state, capable of accommodating and conducting free electrons, are far less common but valuable in photovoltaics and other electronics.
These disclosed oligomers overcome these issues by adopting both stable n-doped (anionic) and potentially p-doped states, making them effective electron transporters. Their synthesis is straightforward, conducted as a one-step oxidative process using inexpensive monomers under mild conditions at about 40° C. The oligomers demonstrate high thermal stability with decomposition onset above 350° C., making them suitable for solar cell applications. Photocurrent measurements show that oligo(AP-CN) can generate anodic photocurrents significantly higher than gold-coated and fullerene-coated electrodes, indicating a substantial improvement in electron transport.
Claims Coverage
The patent includes one independent claim detailing the method of producing an electrically conducting organic oligomer and its key inventive features.
Method of synthesizing electrically conducting organic oligomers
The process involves preparing an acidic aqueous solution by mixing about 1.6 wt % HCl in deionized water with a monomer to form about a 0.3 M solution, preparing a second aqueous solution containing a sodium persulfate oxidant, mixing these two solutions, and allowing the oxidative reaction to proceed at about 40° C., resulting in an electrically conducting organic oligomer.
The claim focuses on the specific one-step oxidative oligomerization method using defined acidic conditions, sodium persulfate as an oxidant, and reaction temperature control to synthesize electrically conducting organic oligomers efficiently.
Stated Advantages
The oligomers have highly variable redox states and good electron-transporting properties.
They are easy to synthesize in a single step plus purification and use inexpensive starting materials.
They exhibit high thermal stability with decomposition onset above 350° C., making them suitable for solar cell applications.
Oligo(AP-CN) generates anodic photocurrents significantly greater than gold-coated and fullerene-coated electrodes, demonstrating superior electron transport performance.
The oligomers can be both n-dopable and p-dopable, an unusual property that enhances their utility in electronic applications.
They are soluble in common polar organic solvents, enabling easy processing into films.
Documented Applications
Use in polymer solar cells as electron transporters to increase photovoltaic efficiency.
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