A key challenge of harvesting solar energy for chemical transformations is the scarcity of photocatalysts with broad activation wavelength and easily tunable band structures. Here, we introduce lead halide perovskite (CsPbBr 3 ) nanocrystals as band-edge-tunable photocatalysts for efficient photoinduced electron/energy transfer−reversible addition−fragmentation chain transfer (PET-RAFT) polymerization. PET-RAFT polymerization of various functional monomers is successfully conducted using a broad range of irradiation sources ranging from blue to red light (460 to 635 nm), resulting in polymer products with narrow dispersity (Đ = 1.02−1.13) and high degree of chain-end fidelity. Furthermore, the giant two-photon absorption cross-section of CsPbBr 3 enables activation with a light source in the near-infrared region (laser pulses centered at 800 nm) for the PET-RAFT process.

Controlling the morphology of polymer semiconductors remains a fundamental challenge that hinders their widespread applications in electronic and optoelectronic devices and commercial feasibility. Although conjugated polymer nanowires (NWs) are envisioned to afford high charge-carrier mobility, the alignment of preformed conjugated polymer NWs has not been reported. Here, we demonstrate an extremely simple and effective strategy to generate well-aligned arrays of one-dimensional (1D) polymer semiconductors that exhibit remarkable enhancement in charge transport using a solution shear-coating technique. We show that solution shear coating of poly(alkylthiophene) NWs induces extension or coplanarization of the polymer backbone and highly aligned network films, which results in enhanced intra- and intermolecular ordering and reduced grain boundaries. Consequently, highly aligned poly(3-hexylthiophene) NWs exhibited over 33-fold enhancement in the average carrier mobility, with the highest mobility of 0.32 cm(2) V(-1) s(-1) compared to pristine films. The presented platform is a promising strategy and general approach for achieving well-aligned 1D nanostructures of polymer semiconductors and could enable the next generation of high-performance flexible electronic devices for a wide range of applications.

Covalent organic frameworks (COFs) are crystalline organic materials of interest for a wide range of applications due to their porosity, tunable architecture, and precise chemistry. However, COFs are typically produced in powder form and are difficult to process. Herein, we report a simple and versatile approach to fabricate macroscopic, crystalline COF gels and aerogels. Our method involves the use of dimethyl sulfoxide as a solvent and acetic acid as a catalyst to first produce a COF gel. The COF gel is then washed, dried, and reactivated to produce a pure macroscopic, crystalline, and porous COF aerogel that does not contain any binders or additives. We tested this approach for six different imine COFs and found that the crystallinities and porosities of the COF aerogels matched those of COF powders. Electron microscopy revealed a robust hierarchical pore structure, and we found that the COF aerogels could be used as absorbents in oil–water separations, for the removal of organic and inorganic micropollutants, and for the capture and retention of iodine. This study provides a versatile and simple approach for the fabrication of COF aerogels and will provide novel routes for incorporating COFs in applications that require macroscopic, porous materials.

Light-mediated radical polymerization has benefited from the rapid development of photoredox catalysts and offers many exceptional advantages over traditional thermal polymerizations. Nevertheless, the majority of the work relies on molecular photoredox catalysts or expensive transition metals. We exploited the capability of semiconductor quantum dots (QD) as a new type of catalyst for the radical polymerization that can harness natural sunlight. Polymerizations of (meth)­acrylates, styrene, and construction of block copolymers were demonstrated, together with temporal control of the polymerization by the light source. Photoluminescence experiments revealed that the reduction of alkyl bromide initiator by photoexcited QD is the key to this light-mediated radical polymerization.