Thermally Activated Aromatic Ionic Dopants (TA-AIDs) Enabling Stable Doping, Orthogonal Processing and Direct Patterning

Doping plays a critical role in organic electronics, and dopant design has been central in the development of functional and stable doping. In this study, there is departure from conventional molecular dopants and a new class of dopants are reported - aromatic ionic dopants (AIDs). AIDs consist of a pair of aromatic cation and anion that are responsible for molecular doping reaction and charge balancing separately. It is shown that the first AID made from cycloheptatrienyl (tropylium) cation and pentacyanocyclopentadienide anion (PCCp), abbreviated as T-PCCp, can function as an effective p-type dopant to dope polydioxythiophenes. Here, tropylium cation induces the doping reaction while the PCCp anion stabilizes the generated polarons and bipolarons. With T-PCCp, a highly doped (approximate to 120 S/cm) and stable system is achieved up to 150 degrees C, an orthogonal (sequential)solution processing resulting from the immiscibility of the dopant and the polymer host, and a high-resolution direct micropatterning with laser writing resulted from a thermally activated doping process.

Automated summary

This study reports a new class of dopants, aromatic ionic dopants (AIDs), which can effectively dope polydioxythiophenes and achieve highly doped and stable systems. The AIDs also facilitate orthogonal solution processing and high-resolution direct micropatterning with laser writing.