Open-shell Oligo(3,4-dioxythiophene) Radical: Synthesis and Photothermal Conversion Performance

Abstract

Open-shell radical meterials have received worldwide attention due to its potential application in highly efficient photothermal conversion field. However, it is still a challenge to enhance the chemical and photothermal stability of the open-shell small molecules and polymers. Herein, a stable open-shell oligo(3,4-dioxythiophene) radical PTTO2 was readily synthesized via simple BBr3-demethylation of the copolymer PTTOMe2 precursor prepared using cheap raw materials. The open-shell character of PTTO2 was carefully studied and confirmed via the signal-silent 1H-NMR spectrum, highly enhanced electron spin resonance signal comparing with PTTOMe2, as well as the ultral-wide UV-vis-NIR absorption and FTIR spectra and other technologies. Surprisingly, the powder of PTTO2 exhibit extremely wide absorption range from 300 to 2500 nm. The powder of PTTO2 can reach 274 ℃ under the same irradiation of 1.2 W cm-2, which is much higher 108 ℃ of the PTTOMe2. To date, PTTO2 stands as one of the low cost pure organic photothermal materials with super-high photothermal conversion performances.