Researchers developed degradation-assisted doping that generates up to 100 times more mobile charges, potentially improving flexible electronics, optoelectronics, and thermoelectric devices through higher conductivity performance.
Researchers from the Institut national de la recherche scientifique (INRS), Concordia University, and York University have developed a degradation-assisted doping (DAD) method that can generate up to 100 times more mobile electrical charges in organic semiconductors than conventional approaches. The technique could help improve materials used in flexible electronics and other lightweight electronic devices.
Organic semiconductors are carbon-based materials that can conduct electricity while remaining thin, lightweight, and suitable for flexible processing. Their electrical performance depends heavily on doping, which increases the concentration of mobile charge carriers. However, conventional chemical doping can eventually reach chemical and thermodynamic limits.
The new DAD approach addresses this limitation by allowing the dopant to effectively remove itself from the reaction after transferring an electron. Researchers demonstrated the method using P3HT, an organic semiconductor, and tris(pentafluorophenyl)borane (BCF) as the dopant.
Laboratory experiments and computer simulations were used to investigate the chemical processes involved. The team employed techniques including nuclear magnetic resonance, optical spectroscopy, electron paramagnetic resonance, and calorimetry to track the changes occurring after electron transfer.
The experiments showed that BCF undergoes degradation after accepting an electron. Its breakdown products no longer interfere with subsequent doping reactions, allowing additional dopant molecules to continue transferring electrons. This helps increase the concentration of mobile charges beyond the levels achievable through conventional doping.
Researchers also observed higher conductivity in P3HT when using BCF compared with other commonly used dopants. The findings indicate that controlling what happens to a dopant after charge transfer can be as important as the initial electron-transfer process.
The approach could support flexible electronics, optoelectronic devices, and thermoelectric technologies, where improved conductivity can enhance device performance. It may also guide the development of dopants designed to degrade in controlled ways after performing their charge-transfer function.
The research does not yet demonstrate a finished commercial electronic device or commercial-scale manufacturing process. Instead, it establishes a chemical mechanism for achieving higher doping levels in organic semiconductor materials. The study was published in Nature Materials.
