A nonconjugated radical polymer glass with high electrical conductivity

Abstract

Solid-state conducting polymers usually have highly conjugated macromolecular backbones and require intentional doping in order to achieve high electrical conductivities. Conversely, single-component, charge-neutral macromolecules could be synthetically simpler and have improved processibility and ambient stability. We show that poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), a nonconjugated radical polymer with a subambient glass transition temperature, underwent rapid solid-state charge transfer reactions and had an electrical conductivity of up to 28 siemens per meter over channel lengths up to 0.6 micrometers. The charge transport through the radical polymer film was enabled with thermal annealing at 80°C, which allowed for the formation of a percolating network of open-shell sites in electronic communication with one another. The electrical conductivity was not enhanced by intentional doping, and thin films of this material showed high optical transparency.

Anti‐Oxidizing Radical Polymer‐Incorporated Perovskite Layers and their Photovoltaic Characteristics in Solar Cells

“…The fluorescence time courses of the FTO/compact TiO 2 /m‐TiO 2 /perovskite devices with and without the incorporation of PTMA (Figure b) revealed a significant decrease in lifetime ( τ 1 =43 to 37 μs, τ 2 =143 to 120 μs, without and with the PTMA incorporation, respectively), suggesting a charge transport from the perovskite surface to the incorporated PTMA. It has recently been highlighted that a TEMPO radical polymer acts as an efficient charge carrier with a tremendously high conductivity based on its high redox activity even in solid‐state devices . PTMA could work both as a carrier mediator in the perovskite layer and an eliminating agent of O 2 .− .…”

“…It has recently been highlighted that aT EMPO radical polymer acts as an efficient charge carrierw ith at remendously high conductivity based on its high redox activity even in solid-state devices. [48] PTMA could work both as ac arrierm ediatori nt he perovskite layer and an eliminating agent of O 2 C À . PTMA is ah ydrophobic polymer and its incorporation improvedt he water-repelling properties of the perovskite layer.T he contact angle of the perovskite layer (vs. water) was increased from 408 to 648 and 808 simply by incorporating 0.3a nd 1.0 wt %P TMA, respectively ( Figure S9), making it more hydrophobic than the layer incorporating PMMA (688 for the perovskite layer with the addition of 1.0 wt %P MMA).…”

“…The charge‐transporting capability of the TEMPO polymers in solid state via a hopping conduction between the TEMPO moieties or hole mobility in solid state was also described . Recently, Boudouris and co‐workers reported the high charge‐transporting capability of the TEMPO polymer . The TEMPO polymers have been also studied as an environmentally benign redox catalyst in biomedical and medical applications, where the TEMPO radical eliminates O 2 .− even in the vapor phase …”

“…[45][46][47] Recently,B oudouris and co-workersr eported the high charge-transporting capability of the TEMPO polymer. [48,49] The TEMPO polymers have been also studied as an environmentally benign redox catalyst in biomedical and medical applications, where the TEMPO radical eliminates O 2 C À even in the vapor phase. [50,51] Herein, we incorporated, for the first time, the redox-active TEMPO radical polymer in ap erovskite layer to successfully improve the durability in an oxygen-containinga tmosphere and describedi ts effect in the significant suppressiono ft he degradation of perovskite compounds.…”

How to Install TEMPO in Dielectric Polymers—Their Rational Design toward Energy‐Storable Materials

“…PTMA samples synthesized by anionic, atom transfer radical polymerization (ATRP), and reversible addition‐fragmentation chain transfer polymerization (RAFT) methods were carefully proved to show low electric conductivity as the bulk material . However, Boudouris and co‐workers recently reported high electric conductivity upon the critical condition that the characteristic length scale is ≈600 nm . Radical polymers could exhibit alterative charge transport under a strong electric field, which affects the dielectric properties of organic polymers.…”