Organic Electropolymerized Multilayers for Light-Emitting Diodes and Displays

Shape-Selective Molecular Separations Enabled by Rigid and Interconnected Confinements Engineered in Conjugated Microporous Polymer Membranes

Separating molecules with similar sizes but different shapes is essential yet challenging. Here, conjugated microporous polymer (CMP) membranes with narrowly distributed network pores are prepared by diffusion-modulated electropolymerization. This approach precisely controls the monomer diffusion and coupling processes, regulating the crosslinking degree to prevent broad aggregate pores and microporous defects. By altering carbazole-based backbones, pore size and pore connectivity are adjusted. The rigid and interconnected confinements restrict molecular rotation and vibration, enforcing consistent shapes and orientations. This enables the separation of solute molecules (≈1000 g mol-1) with linear and bulky shapes, achieving separation factors of up to 134. When pore size is reduced to angstrom scale (≈5 Å), molecular shape significantly influences organic liquid transport. The CMP membranes demonstrate all-liquid phase separation of linear/branched alkane isomers (<100 g mol-1), enriching hexane to 63.35 mole% from equimolar isomer mixture and achieving permeance orders of magnitude higher than those of state-of-the-art membranes.

Carbazole-Bearing Conjugated Microporous Polymer Electrodes for Uranium Extraction from Seawater with Good Anti-biofouling Feature

Emerging electrochemical uranium extraction from seawater offers a promising route for a sustainable fuel supply for nuclear reactor operation. In this work, we intentionally synthesized a conjugated microporous polymer (CMP) with π-conjugated skeletons and permanent porosity, which was induced by in situ electropolymerization on flexible carbon cloths, followed by postdecorating amidoxime groups to create functional materials (CMP-AO). Driven by an extra asymmetrical alternating current electrochemical extraction, the self-supporting and binder-free electrode is exceptionally capable of selectively and rapidly capturing U(VI) from simulated solution, affording an extraction capacity of ∼1806.4 mg/g without saturation. Experimental observation in combination with ex/in situ spectroscopy revealed that CMP-AO enabled surface selective binding sites (amidoxime groups) to U(VI), followed by electrocatalytic reduction (carbazole groups) to yield yellow precipitates (Na2O(UO3·H2O) x ) via reversible electron transfer in the presence of sodium electrolyte. Furthermore, the integrating adsorption-electrocatalysis system achieved an extraction capacity of 18.8 mg/g in real seawater for 21 days and good antibiofouling abilities, validating its feasibility for practical application.

Selective Gain in a Periodic Array of Nano-organic Light-Emitting Diodes

We report nanoscale organic light-emitting diodes (OLEDs) arranged periodically into a large-area array, which produces an amplified emission with a selected spectrum in a narrow band. These nano-OLEDs share a common active layer of super yellow light-emitting PPV copolymer (SY-PPV), which acts both as a waveguide and as a gain channel for the light-emitting signals. The periodic structure supplies Bragg-like diffraction of the emission from SY-PPV under electrical excitation so that the electroluminescence signal is coupled into and confined in the SY-PPV waveguide. During propagation, the waveguide resonance mode interacts with the nano-OLED region and gains amplification. Both the waveguide resonance mode and the output coupling process have strong spectral selectivity, so that the amplification is observed within a spectrum as narrow as 32 nm at FWHM. Such a nano-OLED design not only defines a new scheme of nano-OLEDs, but also proposes potential approaches for electrically pumped organic lasers.

Preparation of Patterned and Multilayer Thin Films for Organic Electronics via Oxygen-Tolerant SI-PET-RAFT

An oxygen-tolerant approach is described for preparing surface-tethered polymer films of organic semiconductors directly from electrode substrates using polymer brush photolithography. A photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) approach was used to prepare multiblock polymer architectures with the structures of multi-layer organic light-emitting diodes (OLEDs), including electron-transport, emissive, and hole-transport layers. The preparation of thermally activated delayed fluorescence (TADF) and thermally assisted fluorescence (TAF) trilayer OLED architectures are described. By using direct photomasking as well as a digital micromirror device, we also show that the surface-initiated (SI)-PET-RAFT approach allows for enhanced control over layer thickness, and spatial resolution in polymer brush patterning at low cost.

Enhancing the Operability of Photoexcitation-Controlled Aggregation-Induced Emissive Molecules in the Organic Phase

Controllable aggregation-induced emission luminogens (AIEgens) by photoexcitation can be conducted within a single solvent, thus opening new opportunities for preparing and processing smart materials. However, undesired side-reactions like photooxidation that can easily occur in the organic phase remain, limiting their applications. To enhance the operability of photoexcitation-controlled AIEgens (to specifically produce a phosphorescence characteristic) in the organic phase, in this work, we employ a typical prototype, hexathiobenzene, usually as the specific phosphorescent group, and investigate a series of physical and chemical factors, such as light intensity, dissolved oxygen content, and solvent polarity, to explore ways to control the photoexcitation-controllable AIEgens against the impurities from side-reactions. An organogel strategy was also developed to minimize interference factors and improve the practical application ability. We believe that the presented results provide new insights into the further development of the photoexcitation-based functional materials and the promotion of their practical usage.