High-Efficiency Intrinsically Thermoplastic Semiconducting Polymer with Excellent Strain-Tolerance Capacity for Flexible Ultra-Deep-Blue Polymer Light-Emitting Diodes.

Complex internal stresses that appear in flexible thin-film electronic devices under long-term deformation operation are associated with incompatible mechanical properties of the multiple layers, which potentially cause intralayer fracture and separation. These defects may result in device instability, performance loss, and failure. Herein, a thermoplastic functional strategy is proposed for manufacturing high-performance stretchable semiconducting polymers with excellent strain-tolerance capacities for flexible electronic devices.

Intrinsically stretchable fully π-conjugated polymers with inter-aggregate capillary interaction for deep-blue flexible inkjet-printed light-emitting diodes.

Fully π-conjugated polymers consisting of plane and rigid aromatic units present a fantastic optoelectronic property, a promising candidate for printed and flexible optoelectronic devices. However, obtaining high-performance conjugated polymers with an excellent intrinsically flexible and printable capacity is a great challenge due to their inherent coffee-ring effect and brittle properties. Here, we report an asymmetric substitution strategy to improve the printable and stretchable properties of deep-blue light-emitting conjugated polymers with a strong inter-aggregate capillary interaction for flexible printed polymer light-emitting diodes.

Intrinsically stretchable fully π-conjugated polymer film via fluid conjugated molecular external-plasticizing for flexible light-emitting diodes.

Fully π-conjugated polymers with rigid aromatic units are promising for flexible optoelectronic devices, but their inherent brittleness poses a challenge for achieving high-performance, intrinsically stretchable fully π-conjugated polymer. Here, we are establishing an external-plasticizing strategy using semiconductor fluid plasticizers (Z1 and Z2) to enhance the optoelectronic, morphological, and stretchable properties of fully π-conjugated polymer films for flexible light-emitting diodes. The synergistic effect of hierarchical structure and optoelectronic properties of Z1 in poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) films enable excellent stretchable deformability (~25%) and good conductivity.

Elastic-Plastic Fully π-Conjugated Polymer with Excellent Energy Dissipation Capacity for Ultra-Deep-Blue Flexible Polymer Light-Emitting Diodes with CIE = 0.04.

Emerging intrinsically flexible fully π-conjugated polymers (FπCPs) are a promising functional material for flexible optoelectronics, attributed to their potential interchain interpenetration and entanglement. However, the challenge remains in obtaining elastic-plastic FπCPs with intrinsic robust optoelectronic property and excellent long-term and cycling deformation stability simultaneously for applications in deep-blue flexible polymer light-emitting diodes (PLEDs). This study, demonstrates a series of elastic-plastic FπCPs (P1-P4) with an excellent energy dissipation capacity via side-chain internal plasticization for the ultra-deep-blue flexible PLEDs.

Triphenylamine Spirofunctionalized Light-Emitting Conjugated Polymer with an Ultradeep-Blue Narrowband Emission for Large-Area Printed Display.

Emerging printed large-area polymer light-emitting diodes (PLEDs) are essential for manufacturing flat-panel displays and solid lighting devices. However, it is challenging to obtain large-area and stable ultradeep-blue PLEDs because of the lack of light-emitting conjugated polymers (LCPs) with robust deep-blue emissions, excellent morphological stabilities, and high charging abilities. Here, a novel unsymmetrically substituted polydiarylfluorene (POPSAF) is obtained with stable narrowband emission for large-area printed displays via triphenylamine (TPA) spirofunctionalization of LCPs.

Intrinsically Stretchable and Efficient Fully Π-Conjugated Polymer via Internal Plasticization for Flexible Deep-Blue Polymer Light-Emitting Diodes with CIE = 0.08.

Intrinsically stretchable polymeric semiconductors are essential to flexible polymer light-emitting diodes (PLEDs) owing to their excellent strain tolerance capacity under long-time deformation operation. Obtaining intrinsic stretchability, robust emission properties, and excellent charge-transport behavior simultaneously from fully π-conjugated polymers (FCPs) is difficult, particularly for applications in deep-blue PLEDs. Herein, an internal plasticization strategy is proposed to introduce a phenyl-ester plasticizer into polyfluorenes (PF-MC4, PF-MC6, and PF-MC8) for narrowband deep-blue flexible PLEDs.

Photoexcitation dynamics and energy engineering in supramolecular doping of organic conjugated molecules.

Doping and blending strategies are crucial means to precisely control the excited states and energy level in conjugated molecular systems. However, effective models and platforms are rarely proposed to systematically explore the effects of the formation of trapped doped centers on heterogeneous structures, energy level and ultrafast photophysical process. Herein, for deeply understanding the impact of molecular doping in film energy levels and photoexcitation dynamics, we set a supramolecular N-B coordination composed by the conjugated molecules of pyridine functionalized diarylfluorene (host material), named as ODPF-Phpy and ODPF-(Phpy), and the molecule of tris(perfluorophenyl)borane (BCF) (guest material).

Large-Area Blade-Coated Deep-Blue Polymer Light-Emitting Diodes with a Narrowband and Uniform Emission.

Large-area polymer light-emitting diodes (PLEDs) manufactured by printing are required for flat-panel lighting and displays. Nevertheless, it remains challenging to fabricate large-area and stable deep-blue PLEDs with narrowband emission due to the difficulties in precisely tuning film uniformity and obtaining single-exciton emission. Herein, efficient and stable large-area deep-blue PLEDs with narrowband emission are prepared from encapsulated polydiarylfluorene.

Improving the Intrinsic Stretchability of Fully Conjugated Polymer for Deep-Blue Polymer Light-Emitting Diodes with a Narrow Band Emission: Benefits of Self-Toughness Effect.

It is challenging to construct the intrinsically stretchable active layer of rigid conjugated polymers (CPs) toward flexible deep-blue light-emitting diodes (FLEDs). Inspired by the self-toughness effect, sacrificial hydrogen bonding (H-bonding) and a cross-linked network synergistically enabled polydiarylfluorene (PFs-NH) films to present efficient deep-blue emission and excellent intrinsic stretchability. In particular, a cross-linked network structure presenting viscoelasticity behaviors, which was successfully inherited into postprocessed films with interchain interpenetration and a crystallinity domain and behaved as energy absorption and dissipation centers, was induced by the interchain H-bonding interaction in toluene (Tol) precursor solutions where the storage moduli (') gradually exceeded the loss moduli (″).

Hierarchical Uniform Supramolecular Conjugated Spherulites with Suppression of Defect Emission.

Easily processed, well-defined, and hierarchical uniform artificial architectures with intrinsic strong crystalline emission properties are necessary for a range of light-emitting optoelectronic devices. Herein, we designed and prepared ordered supramolecular spherulites, comprising planar conformational molecules as primary structures and multiple hydrogen bonds as physical cross-links. Compared with serious aggregation-induced fluorescence quenching (up to 70%), these highly ordered architectures exhibited unique and robust crystalline emission with a high PLQY of 55%, which was much higher than those of other terfluorenes.

Ultrastable Supramolecular Self-Encapsulated Wide-Bandgap Conjugated Polymers for Large-Area and Flexible Electroluminescent Devices.

Controlling chain behavior through smart molecular design provides the potential to develop ultrastable and efficient deep-blue light-emitting conjugated polymers (LCPs). Herein, a novel supramolecular self-encapsulation strategy is proposed to construct a robust ultrastable conjugated polydiarylfluorene (PHDPF-Cz) via precisely preventing excitons from interchain cross-transfer/coupling and contamination from external trace H O/O . PHDPF-Cz consists of a mainchain backbone where the diphenyl groups localize at the 9-position as steric bulk moieties, and carbazole (Cz) units localize at the 4-position as supramolecular π-stacked synthon with the dual functionalities of self-assembly capability and hole-transport facility.

Photophysical and Fluorescence Anisotropic Behavior of Polyfluorene β-Conformation Films.

We demonstrate a systematic visualization of the unique photophysical and fluorescence anisotropic properties of polyfluorene coplanar conformation (β-conformation) using time-resolved scanning confocal fluorescence imaging (FLIM) and fluorescence anisotropy imaging microscopy (FAIM) measurements. We observe inhomogeneous morphologies and fluorescence decay profiles at various micrometer-sized regions within all types of polyfluorene β-conformational spin-coated films. Poly(9,9-dioctylfluorene-2,7-diyl) (PFO) and poly[4-(octyloxy)-9,9-diphenylfluoren-2,7-diyl]-co-[5-(octyloxy)-9,9-diphenylfluoren-2,7-diyl] (PODPF) β-domains both have shorter lifetime than those of the glassy conformation for the longer effective conjugated length and rigid chain structures.

Steric-Hindrance-Functionalized Polydiarylfluorenes: Conformational Behavior, Stabilized Blue Electroluminescence, and Efficient Amplified Spontaneous Emission.

Control of the hierarchical molecular organization of polydiarylfluorenes by synthetic strategies is significant for optimizing photophysical properties as well as the performance of light-emitting devices. Herein, for the suppression of molecular aggregation and enhancement of luminescence efficiency, a series of steric units were introduced into polydiarylfluorenes by copolymerization, with the aim of integrating the advantages of the steric-hindrance effect and of the β-phase. Optical and Raman spectroscopies revealed a β-phase conformation for a polymer copolymerized with spiro[fluorene-9,9'-xanthene] (SFX), with photoluminescence (PL) peaks at 454, 482, and 517 nm.