Solution-Based Large-Area Assembly of Coaxial Inorganic-Organic Hybrid Nanowires for Fast Ambipolar Charge Transport.

Abstract

Donor-acceptor interfacial microstructures and fast ambipolar charge transport are pivotal in determining the device performance of inorganic-organic hybrid photovoltaics. Here, we report on a series of one-dimensional coaxial p-n junction core-shell nanohybrids formed by direct side-on attachment of carboxylated poly(3-alkylthiophene)s onto single-crystalline ZnO nanowires. The diameter of pristine ZnO nanowires is ∼30 nm, and the conjugated polymer forms a 2-10 nm shell around each nanowire. Spectroscopic studies on the resulting core-shell hybrid nanowires show an elongated conjugation length of the poly(3-alkylthiophene) backbone and fast electron transfer via ordered donor-acceptor interfaces. Hybrid nanowires in suspensions spontaneously undergo phase transitions from isotropic to nematic liquid crystalline phases via a biphasic region with increasing concentration. The unique liquid crystalline elasticity of nanohybrids results in large-area monodomain structures of aligned hybrid nanowires under simple shear flow, which are maintained in the dried film used for device fabrication. These methodologies provide a mechanism for controlling donor-acceptor interfaces and exploiting lyotropic liquid crystallinity for solution-based processing of large-area alignment of photovoltaic elements with anisotropic charge transport for hybrid photovoltaic devices.