POS6-1233
Highly Crystalline Donor-Acceptor Polymer Nanowires via Crystallization-Driven Self-Assembly for Efficient Photocatalytic Hydrogen Evolution
When and Where
Nov 30, -0001
00:00 - 00:00
Room 301 (Grand Ballroom)
Presenter(s)
Kim Hyojun (Gwangju institute of science and technology)
Co-Author(s)
Abstract
Polythiophene-based donors absorb visible light strongly, but their photocatalytic efficiency is limited by short exciton diffusion lengths and rapid charge recombination. Most excitons therefore decay before reaching a reactive interface. Donor-acceptor (D-A) heterojunctions can overcome this limitation. Conventional bulk-heterojunction blends, however, form disordered domains that are difficult to control. To overcome this, we use crystallization-driven self-assembly (CDSA), rather than covalent synthesis, to build a donor-acceptor (D-A) heterojunction with an orthogonal geometry: a crystalline acceptor forms the nanowire axis, and the donor grows perpendicular to it as secondary nanowires. This keeps every donor domain within an exciton diffusion length of the D-A interface, so excitons dissociate before recombining. The orthogonal geometry also separates the two carriers. Holes migrate along the donor backbone. Electrons are extracted into the acceptor domains. Directional molecular packing defines the interface and the transport pathways at the molecular level. This yields uniform and highly crystalline nanowires that are inaccessible by conventional blending. Cryo-TEM resolves the crystalline D-A interface and the epitaxial registry between the donor and acceptor domains. Photoreduction then deposits a Pt cocatalyst at the electron-rich domains, and under visible-light absorption the nanowires drive efficient photocatalytic hydrogen evolution, offering a new route to high-efficiency organic photocatalysts. The selective deposition confirms directional charge separation at the junction. The assembled shish-kebab nanowires also show enhanced activity over single-component and disordered controls. This establishes crystallization-driven control of an orthogonal p-n junction as a generalizable strategy for organic photocatalysis.
