Pyridine End-Capped Polymer to Stabilize Organic Nanoparticle Dispersions for Solar Cell Fabrication through Reversible Pyridinium Salt Formation

Bulk-heterojunction nanoparticle dispersions in water or alcohol can be employed as eco-friendly inks for the fabrication of organic solar cells by printing coating. However, one major drawback is need stabilizing surfactants, which facilitate formation but later hamper device performance. When surfactant-free are formulated, a strong limitation imposed dispersion concentration due to tendency nanoparticles aggregate. In this work, pyridine end-capped poly(3-hexylthiophene) (P3HT-Py) synthesized and included an additive stabilization P3HT:indene-C60 bis-adduct (ICBA) dispersions. presence acetic acid (AcOH), surface-active pyridinium acetate P3HT ion pair, P3HT-PyH+AcO–, formed effectively stabilizes hence allows with smaller sizes higher concentrations up 30 mg/mL methanol. The exhibit enhanced shelf-lifetime at least 60 days room temperature. After deposition light-harvesting layers from dispersions, ion-pair reversed elevated temperatures leading regeneration P3HT-Py AcOH. AcOH evaporates active layer, while performance corresponding not affected residual devices. Enhanced stability achieved only 0.017 wt % P3HT/ICBA formulation.