Ground-state electron transfer in all-polymer donor–acceptor heterojunctions

Ruoko

ACS Appl. Mater. Interfaces

et al. 2020

Self Cite

Doping of organic semiconductors is a powerful tool to optimize the performance of various organic (opto)electronic and bioelectronic devices. Despite recent advances, the low thermal stability of the electronic properties of doped polymers still represents a significant obstacle to implementing these materials into practical applications. Hence, the development of conducting doped polymers with excellent long-term stability at elevated temperatures is highly desirable. Here, we report on the sequential doping of the ladder-type polymer poly(benzimidazobenzophenanthroline) (BBL) with a benzimidazole-based dopant (i.e., N-DMBI). By combining electrical, UV–vis/infrared, X-ray diffraction, and electron paramagnetic resonance measurements, we quantitatively characterized the conductivity, Seebeck coefficient, spin density, and microstructure of the sequentially doped polymer films as a function of the thermal annealing temperature. Importantly, we observed that the electrical conductivity of N-DMBI-doped BBL remains unchanged even after 20 h of heating at 190 °C. This finding is remarkable and of particular interest for organic thermoelectrics.

Section: Resultsmentioning

confidence: 99%

“…However, because of the high surface pressure of TDAE and its reactivity with molecular oxygen, 44 the electrical properties of vapor-doped BBL films are typically not stable under ambient conditions and degrade quickly at elevated temperatures. 35 …”

Section: Introductionmentioning

confidence: 99%

Sequential Doping of Ladder-Type Conjugated Polymers for Thermally Stable n-Type Organic Conductors

Ruoko

ACS Appl. Mater. Interfaces

et al. 2020

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“…Electrical doping of organic semiconductors has been attracting a lot of attention as an effective strategy to tune their electrical, optical, and structural properties. [ 1–9 ] Recently, novel doping mechanism and phenomena have been reported, such as ion‐exchange assisted doping, [ 3,4 ] double doping, [ 5 ] ultraviolet light‐activated doping, [ 6 ] limited depth doping in films, [ 7 ] and polymer‐polymer mixing doping in the ground state. [ 8 ] These doping behaviors are substantially different from those in traditional inorganic semiconductors (such as silicon, gallium arsenide).…”

Section: Introductionmentioning

confidence: 99%

Efficient Electrical Doping of Organic Semiconductors Via an Orthogonal Liquid‐Liquid Contact

Sun

Yang

Dong

et al. 2021

Adv Funct Materials

Doping is an effective strategy to tune the electrical properties of organic semiconductors. Traditional solution‐processed doping methods, including “host‐dopant mixing‐doping” and “post‐fabrication doping” methods, present challenges for their use in applications in optoelectronic devices. This work reports about a novel method to prepare electrically doped films, the authors call orthogonal liquid‐liquid‐contact (OLLC) doping. In OLLC doping, dopant and polymer semiconductors are dissolved in water and an organic solvent, respectively, and electrical doping occurs during film formation at the orthogonal liquid‐liquid (aqueous‐organic) interface. A large free volume of polymer and dopant in their solutions enables diffusion for effective doping. Thanks to the high surface tension of water, nanometer‐thick polymer films form spontaneously on the aqueous surface and simultaneously get doped. The doped thin polymer films on the aqueous surface can be easily transferred to devices to facilitate hole collection/injection in organic photovoltaics and light‐emitting diodes with solution‐processed top electrodes.

Advanced Energy Materials

“…[19] Recently, the blend of BBL with a p-type polymer leads to the first polymer charge transfer salt. [28] However, to the best of our knowledge, n-doped conducting polymers have not been investigated in ORR or in any associated applications. The effect of polymer conductivity on the efficiency of ORR electrocatalysis.…”

Section: Introductionmentioning

confidence: 99%

Negatively‐Doped Conducting Polymers for Oxygen Reduction Reaction

Vagin

Gueskine

Mitraka

et al. 2020

Self Cite

The oxygen reduction reaction (ORR) limits the efficiency of oxygen‐associated energy conversion in fuel cells and air‐metal batteries. Today, expensive noble metal catalysts are often utilized to enhance the ORR and the resulting conversion efficiency in those devices. Hence, there is an intensive research to find efficient electrodes, exhibiting a favorable electronic structure, for ORR based on abundant materials that can be manufactured using low cost processes. In that context, metal‐free carbon‐based nanostructures and conducting polymers have been actively investigated. The negatively doped poly(benzimidazobenzophenanthroline) (BBL) as an efficient and stable oxygen cathode material is reported here. Compared to the benchmark p‐doped conducting polymer poly(3,4‐ethylendioxythiophene) (PEDOT), the BBL provides electrocatalysis that fully reduces dioxygen into water, via a (2 + 2)‐electron transfer pathway with hydrogen peroxide (H2O2) as an intermediate; while PEDOT limits the ORR to H2O2. It is demonstrated that n‐doped BBL is a promising air electrode material for low‐cost and ecofriendly model fuel cells, without the need of any co‐catalysts, and its performance is found to be superior to p‐doped PEDOT air electrodes.