Coaxial Conjugated Polymer/Quantum Rod Assembly into Hybrid Nanowires with Preferred Quantum Rod Orientation

Nanoheterojunction wires composed of coaxially aligned organic conjugated polymers (CPs) and inorganic quantum nanoparticles can provide the continuous charge transport pathway in a confined nanoscale domain. However, controlling the location and orientation of the 1D quantum rod (QR) array along the longitudinal axis of the CP nanowire (NW) is challenging due to the complex and competitive assembly of two components. The strong dipole–dipole interaction between QRs with anisotropic nature favors the misalignment of QRs. Herein, the coupling modes (end-to-end or side-by-side) of CdSe QRs confined within NWs formed by the crystallization-driven assembly of CPs were precisely controlled by changing the solution processing. Gradual diffusion of a poor solvent at the top layer into a good solvent containing CPs and QRs at the bottom layer provides the preferred end-to-end QR orientation within micrometer-long hybrid NWs. On the other hand, simple and fast mixing of good and poor solvents predominantly enforces side-by-side QR arrays within short hybrid NWs. The competition between CP crystallization and QR dipole–dipole interaction affects the QR orientation within coaxial hybrid NWs. This research provides a deep understanding of mutual self-assembly between CPs and QRs and a fabrication strategy for p-n heterojunction hybrid NWs with customized performance in the solution-processable optoelectronic devices.