Introducing New Highly Soluble High Electron Affinity Molecular Dopants

Molecular dopants are essential to dope semiconducting polymers for any device application. We introduce new highly soluble high electron affinity (EA) molecular dopants for solution doping of high ionization energy (IE) semiconducting polymers. Our new dopants are based on the parent molecule CN6-CP, that has a record EA of 5.87 eV, but is difficult to process. We demonstrate once and twice substituted ester analogs with EA of 5.75 eV and 5.61 eV but high solubility and solution processability. We demonstrate the use of these dopants with a series of alternating diketopyrrolopyrrole (DPP) polymers. All polymers achieve a sequentially doped conductivity of >15 S/cm. We developed a model to measure the doping level and hole density based on measurement of the UV/vis/NIR absorbance. We show doping of up to 80% of sites in the polymer, which prompts an important discussion of the maximum doping level for a conjugated polymer. We present a population model that is consistent across multiple polymers with multiple different molecular dopants. This presentation will reveal new synthesis, excellent materials properties, and a consistent method to quantify doping level across different semiconducting polymers.