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Nonaqueous dispersions of graphene nanoplatelets (GrNPs) can be used to prepare thin films and coatings free of surfactants, but typically involve polar organic solvents with high boiling points and low exposure limits. Here we describe the mechanochemical exfoliation and dispersion of GrNPs in volatile aprotic solvents such as ethyl acetate (EtOAc) and acetone, which rank favorably in green solvent selection guides. GrNPs in powder form were exfoliated with solvent on a horizontal ball mill for 48 hours then sonicated at moderate power, to produce suspensions in excess of 300 µg/mL with minimum loss of dispersion stability over 7 weeks at room temperature. Atomic force microscopy (AFM) of individual particles indicate a median thickness and lateral width of 8‒10 layers and 180 nm, respectively. GrNP films can be deposited by conventional airbrush equipment with a dry time of seconds and applied as layers and coatings that enhance the reproducibility and performance of electronic devices. We demonstrate the utility of spray-coated GrNPs as contact layers for low-cost electrochemical sensing with improvements in intrabatch reproducibility, and as conformal coatings on metal heat sinks with enhanced rates of heat dissipation. 

Abstract 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 effectivep‐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 (≈120 S/cm) and stable system is achieved up to 150 °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.