Enhancing the Deep-Blue Emission Property of Wide Bandgap Conjugated Polymers through a Self-Cross-Linking Strategy

Abstract

Interchain aggregation is adverse to the stability and performance of wide bandgap light-emitting conjugated polymers (LCPs) and their optoelectronic devices, associated with the electron coupling of the backbone chain. Chain-segmental motion is a fundamental factor to cause interchain aggregation under film post-treatment, device fabrication, and Joule self-heating in device operation. Herein, the suppression of the chain motion through the cross-linking chemical successfully avoided the aggregationinduced residual physical defect emission in wide band gap polyfluorene (POEYDPF). Compared to pristine ones, high Young's modulus (E r ) and hardness (H) of cross-linked film effectively confirmed the rigid physical molecular landscape of the POEYDPF chain with low chain segmental motion and dense random interchain packing. According to the ultrafast spectroscopic spectral analysis, this residual defect emission at long wavelength can be suppressed in this rigid cross-linked network. As a result, the crosslinked film presents a deep-blue lasing behavior with an extremely low threshold of 0.70 μJ/cm 2 , attributed to the low optical loss in the cross-linked topological network. Finally, efficient and stable deep-blue PLEDs with three well-resolved emission peaks of single-chain are also fabricated with a high current efficiency (C.E.) of 1.57 cd/A (twice that of the pristine ones).

Intrinsically stretchable and efficient cross-linked small molecular emitter for flexible organic light-emitting diodes

“…1d clearly showed that the QC-H out-of-plane oscillating vibration absorption peaks of F-3OCm appeared at 898 cm À1 and 989 cm À1 , together with the CQC stretching vibration absorption peak at 1627 cm À1 . 48,50 In comparison, it can be found that after annealing at 140 1C for 10 min, the absorption intensity of the RCH = CH 2 feature of F-3OCm annealed films decreased significantly, effectively supporting the intermolecular cross-linked reaction (Fig. S9, ESI †).…”

Fabrication of Highly Fluorescent Temperature-Sensitive Composites Based on a Synergistic Molecular Mechanism between Hydrogen-Bonded/AIEgen-Modified Conjugated Polymers and Polymer Substrates

“…Based on the above discussion, it can be seen that PT-CzNMD/PU has excellent FTS properties. Generally speaking, the matrix cross-linking degree has an important effect on the luminescence properties of a conjugated fluorophore. − Therefore, different cross-linking degrees of the polyurethane matrix were prepared to explore the FTS properties of the PT-CzNMD/PU composite system. As shown in Figure a, two kinds of chain extenders were selected.…”

Vapor‐Phase Growth Strategies of Fabricating Organic Crystals for Optoelectronic Applications

“…[ 102–109 ] The current preparation of organic heterostructures usually adopts bottom‐up self‐assembly techniques in solution. [ 110–114 ] However, it causes many defects, such as edge imperfection, thin film deposits, and uneven surfaces. So, Chandrasekar et al.…”

“…[102][103][104][105][106][107][108][109] The current preparation of organic heterostructures usually adopts bottom-up self-assembly techniques in solution. [110][111][112][113][114] However, it causes many defects, such as edge imperfection, thin film deposits, and uneven surfaces. So, Chandrasekar et al [115] employed a sequential sublimation technique at ambient pressure to combine 1D dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl) 4H-pyran (DCM) micro-rods and 2D α-perylene microsheets.…”