Efficient helical columnar emitters of chiral homoleptic Pt(ii) metallomesogens for circularly polarized electroluminescence.

Chiral organometallic Pt(ii) complexes have been demonstrated to be excellent circularly polarized luminescence (CPL) materials due to their rich phosphorescence and strong self-assembly characteristics. However, it remains a formidable task to simultaneously achieve high luminance () and electroluminescence dissymmetry factor ( ) values for circularly polarized electroluminescence (CP-EL) devices of Pt(ii) complex-based emitters. In this study, we carry out a straightforward and efficient protocol to construct highly CPL-active helical columnar () emitters by using chiral homoleptic triazolatoplatinum(ii) metallomesogens (/-HPt).

Tunable circularly polarized electroluminescence behaviors from chiral co-assembled conjugated liquid crystal polymers.

Chiral co-assembly strategy has proven effective in increasing the dissymmetry factor (g) of the emitting layers (EMLs) in circularly polarized organic light-emitting diodes (CP-OLEDs). Therefore, it is crucial to investigate the molecular structures that facilitate chiral co-assembly for further amplification of circularly polarized electroluminescence (CP-EL) signals. In this study, three types of achiral conjugated liquid crystal (LC) polymers (PFPh, PFNa and PFPy) and chiral binaphthyl-based polymer inducers (R/S-FO) were synthesized to construct corresponding chiral co-assemblies (R/S-FO)-(PFPh/Na/Py) as EMLs for CP-OLEDs through strong intermolecular π-π stacking interactions.

Amplified Circularly Polarized Luminescence Behavior in Chiral Co-assembled Liquid Crystal Polymer Films via the Strategic Manipulation of Chiral Inducers.

One of the most important factors for the future application of circularly polarized luminescence (CPL) materials is their high dissymmetry factors (), and more and more studies are working tirelessly to focus on increasing the value. Herein, we chose an achiral liquid crystal polymer (LC-P) and two chiral binaphthyl-based inducers (/-3 and /-6) with different substitution positions (3,3' positions for /-3 and 6,6' positions for /-6) to construct chiral co-assemblies and explored their induced amplification CPL behaviors. Interestingly, after the thermal annealing treatment, this kind of chiral co-assembly (/-3)-(LC-P) can emit a superior CPL signal (|| = 0.

Strong Circularly Polarized Luminescence Promoted by AIE-active Chiral Co-assemblies in Liquid Crystal Polymer Films.

Recently, extensive works have focused on increasing the dissymmetry factors (g) of various circularly polarized luminescence (CPL) materials, which is one of the most important factors for future applications of CPL. Herein, we designed a chiral co-assembled liquid crystal polymer (LCP) PTZ@R/S-PB2, which was prepared by chiral binary co-polymer (R/S-PB2) doped with achiral phenothiazine derivation dye (PTZ). For comparison, ternary co-polymerized LCP (R/S-PT) was synthesized by co-polymerizing with mesogenic monomer, chiral monomer and emissive monomer.

Light-Driven Sign Inversion of Circularly Polarized Luminescence Enabled by Dichroism Modulation in Cholesteric Liquid Crystals.

Stimuli-responsive circularly polarized luminescence (CPL) materials show great promise in applying information encryption and anticounterfeiting. Herein, light-driven CPL sign inversion is achieved by combining a photoresponsive achiral negative dichroic dye (KG) and a static achiral positive dichroic dye (NR) as dopants at the 0.5:0.

Achiral Dichroic Dyes-mediated Circularly Polarized Emission Regulated by Orientational Order Parameter through Cholesteric Liquid Crystals.

It is noteworthy that cholesteric liquid crystal (CLC) platforms have been witnessed in high-performance circularly polarized luminescence (CPL) behaviors through the highly organized chiral co-assembled arrangement of achiral dyes. However, most CPL-active design strategies are closely relative to the helix co-assembly structure of CLC rather than achiral dyes. Herein, we developed an intriguing regulation strategy for CPL-active CLC materials.

Induced Red Circularly Polarized Luminescence Emission Promoted by Intermolecular Förster Resonance Energy Transfer through a Cholesteric Liquid Crystal Medium.

In this paper, planar chiral helicenes based on [2.2]paracyclophane PCPH5 acted as both chiral inducers and energy donors to construct the circularly polarized luminescence (CPL)-active ternary cholesteric liquid crystals (T-N*-LCs) in a commercial nematic liquid crystal (SLC1717, N-LCs) medium. Induced red CPL emission based on the energy acceptor of the achiral polymer DTBTF8 could be successfully promoted by the intermolecular Förster resonance energy transfer mechanism.

Induced CPL-Active Materials Based on Chiral Supramolecular Co-Assemblies.

Circularly polarized luminescence (CPL) has attracted much interest due to its potential applications on chiral photonic techniques and optoelectronic materials science. As known, dissymmetry factor (g ) of CPL is one essential factor for evaluating the features of CPL-active materials. Much attention has focused on how to increase the g value, which is one of the most important issues for CPL practical applications.

Inverted and Amplified CP-EL Behavior Promoted by AIE-Active Chiral Co-Assembled Helical Nanofibers.

It is well-known that high-performance circularly polarized organic light-emitting diodes (CP-OLEDs) remain a formidable challenge to the future application of circularly polarized luminescent (CPL)-active materials. Herein, the design of a pair of AIE-active chiral enantiomers (L/D-HP) is described to construct chiral co-assemblies with an achiral naphthalimide dye (NTi). The resulting co-assemblies emit an inverted CPL signal compared with that from the L/D-HP enantiomers.

Remarkable White Circularly Polarized Electroluminescence Based on Chiral Co-assembled Helix Nanofiber Emitters.

White circularly polarized organic light-emitting diodes (CP-WOLEDs) are of great significance in potential lighting sources and full-color 3D displays. However, High-performance white CP-EL sources are almost unexplored. We have constructed full-color CP-EL devices based on chiral co-assemblies by using three achiral conjugated pyrene-based dyes (BP, w-WP and c-WP) doped with chiral binaphthyl-based enantiomers (S-/R-M) as the EMLs through an intermolecular chirality induction mechanism.

Dynamically stable and amplified circularly polarized excimer emission regulated by solvation of chiral co-assembly process.

Chiral supramolecular assembly has been assigned to be one of the most favorable strategies for the development of excellent circularly polarized luminescent (CPL)-active materials. Herein, we report our study of an achiral boron-containing pyrene (Py)-based chromophore (PyBO) as a circularly polarized excimer emission (CPEE) dye induced by chiral co-assemblies containing chiral binaphthyl-based enantiomers (R/S-M). Chiral co-assembly R/S-M-(PyBO) fresh film spin-coated from toluene solution can exhibit orderly nanofibers and strong green CPEE (λ = 512 nm, g = ±0.

Dynamic Circularly Polarized Luminescence with Tunable Handedness and Intensity Enabled by Achiral Dichroic Dyes in Cholesteric Liquid Crystal Medium.

Cholesteric liquid crystals (CLCs) are chiral supramolecular systems that self-assemble into a highly regular helical arrangement in a liquid crystal (LC) medium. Such an arrangement is highly beneficial for the chiral enlargement effect on circularly polarized luminescence (CPL) signals. Dichroic dyes with rod-like molecular structures can exhibit fluorescence anisotropy along both the long and short molecular axes owing to their transition dipole moment (TDM) vectors.

Amplified Circularly Polarized Electroluminescence Behavior Triggered by Helical Nanofibers from Chiral Co-assembly Polymers.

Two chiral binaphthyl polymers (R/S-P1 and R/S-P2) with different dihedral angles of the binaphthyl moiety were chosen as chiral inducers to construct chiral co-assemblies with an achiral pyrene-naphthalimide dye (NPy) and then acted as the emitting layer (EML) of circularly polarized electroluminescence (CP-EL) devices. The anchored dihedral angle of R/S-P2 not only exhibited the enhanced chirality signal, but also had a strong chirality-inducing effect on the achiral NPy dye in the chiral co-assembly (R/S-P2) -(NPy) . After annealing at 120 °C, the CPL signal (|g |) of ordered helical nano-fibers (R/S-P2) -(NPy) was amplified to 5.

Inverted Circularly Polarized Luminescence Behavior Induced by Helical Nanofibers through Chiral Co-Assembly from Achiral Liquid Crystal Polymers and Chiral Inducers.

Chiral supramolecular assembly can provide a powerful strategy for developing circularly polarized luminescence (CPL)-active materials by forming helices or superhelices into single or multiple components. Herein, we chose three achiral liquid crystal polymers (/) and chiral binaphthyl-based inducers () with anchored dihedral angles to construct chiral co-assemblies and explore the induced CPL behavior from pyrenyl (Py) emitters in achiral LC polymers through the regulation of helical nanofibers during the supramolecular co-assembly process. Most interestingly, chiral co-assembly emitted an inverted blue-colored CPL signal during thermal annealing treatment at the glass transition temperature due to the flexible main chain of the LC polymer ().

Strong CPL-active liquid crystal materials induced by intermolecular hydrogen-bonding interaction and a chirality induction mechanism.

A novel co-assembly material can emit strong CPL signals ( = 485 nm, = +0.076/-0.064) from an achiral AIE-active β-cyanostilbene (CYS) liquid crystal dye through intermolecular hydrogen bond (HB) interaction and chirality induction after a rapid cooling quench treatment.

Controllable Circularly Polarized Electroluminescence Performance Improved by the Dihedral Angle of Chiral-Bridged Binaphthyl-Type Dopant Inducers.

Chirality of 1,1'-binaphthol (BINOL) is due to the restricted rotation between two naphthalene rings, and its skeletal structure of binaphthyl unit can be further modified by choosing functionalized substituents to afford the enlarged chiral induction effect. In this paper, we designed and synthesized nine chiral binaphthyl derivatives () as circularly polarized electroluminescence (CP-EL) inducers by inserting various bridged alkyl chains into the hydroxyl groups of BINOL or introducing functionalized substituents with different steric hindrances on the 3,3'-position of 2,2'-methylenedioxy-1,1'-binaphthalene. Their molecular conformations and CPL behaviors of nine chiral inducers were significantly dependent on the length of the alkyl chain and the degree of substituent steric hindrance, which could further regulate their chiral induction effect on achiral fluorescent polymer F8BT from small to large in the doped films.

Deep Blue Circularly Polarized Luminescence Response Behavior of an Achiral Pyrene-Based Emitter Regulated by Chiral Co-assembly Helical Nanofibers.

Supramolecular co-assembly provides a brand-new powerful strategy for regulating simple organic molecules into various hierarchical nano- and microstructures as smart functional materials. In particular, chiral supramolecular assemblies with strong fluorescent emission have received extensive attention for their application as circularly polarized luminescence (CPL) emitters. Herein, we synthesized three achiral pyrene derivatives, but only the chiral co-assembly (-NMe2-Py-2) can exhibit the regular and orderly helical nanofiber via π-π stacking interaction between chiral ,'-dimethyl-binaphthyldiamine enantiomers (-NMe2) and the achiral pyrene derivative (Py-2).

Ultrastrong Red Circularly Polarized Luminescence Promoted from Chiral Transfer and Intermolecular Förster Resonance Energy Transfer in Ternary Chiral Emissive Nematic Liquid Crystals.

Chiral emissive liquid crystals (N*-LCs) have been proved to greatly amplify the circularly polarized luminescence (CPL) signals due to highly regular spiral arrangement of dyes in a well-organized liquid crystals system. Normally, CPL materials with a high luminescence dissymmetry factor () and quantum yield (QY) can meet the real application requirement. Here, four chiral aggregate-induced emission (AIE) active donors (Guests A1-A4: -C2, -C4, -C6, -C8, chiral dopant, and energy donor) and achiral AIE-active acceptors (Guest B: PBCy, CPL emitter) were doped into the commercial nematic liquid crystals E7 (N-LCs, Host) to form CPL-active ternary chiral emissive N-LCs (T-N*-LCs), respectively.

Ultrasensitive Nucleic Acid Assay Based on Cyclometalated Iridium(III) Complex with High Electrochemiluminescence Efficiency.

This work developed a sensitive electrochemiluminescence (ECL) biosensor based on a cyclometalated iridium(III) complex ((bt)Irbza), which was synthesized for the first time. Annihilation, reductive-oxidative, and oxidative-reductive ECL behaviors of (bt)Irbza were investigated, respectively. The oxidative-reductive ECL intensity was the strongest compared with the other two, which showed 16.

Strong-Induced CPL Emission Promoted from Achiral Conjugated Polymer-Containing Emissive Nematic Liquid Crystals (P-N*-LCs).

With the rapid development on 3D printing technology, more and more works have been devoted to 3D display. 3D display will really come true by using circularly polarized luminescence (CPL)-active materials with both high quantum yield and dissymmetry factor (g ) in organic light-emitting diode or liquid crystals (LCs). But so far most of these CPL materials cannot meet the real application requirement because of the low g values in the range of 10 -10 .

Aggregation-Induced Electrochemiluminescence of Conjugated Pdots Containing a Trace Ir(III) Complex: Insights into Structure-Property Relationships.

An approach to the design of iridium(III)-contained polytetraphenylethene Pdots that could exhibit highly efficient electrochemiluminescence (ECL) was proposed. The relationships of ECL performance between the iridium complex-embedded and end-capped aggregation-induced emission (AIE) active Pdots in aqueous media were investigated for the first time. The iridium complexes with cyclometalated ligand 6-phenylphenanthridine (pphent) were incorporated into the copolymers by either embedding (, ) or end-capping () into the backbone an ancillary 2,2'-bipyridine (bpy) ligand.

Strong CPL of achiral liquid crystal fluorescent polymer the regulation of AIE-active chiral dopant.

Ternary polymer dispersed cholesteric liquid crystals (PD-CLCs) prepared by doping AIE-active binaphthyl-based molecules (R/S-AD, chiral dopant) and the achiral liquid crystal fluorescent polymer, poly(p-phenylene ethynylene) (LC-PPE, CPL emitter) into 5CB, can emit strong circularly polarized luminescence (CPL) with gem up to 0.97. This work develops a new strategy for designing strong CPL materials.

Solution-Processed White Circularly Polarized Organic Light-Emitting Diodes Based on Chiral Binaphthyl Emitters.

By combining the blue and orange CPL or functionalized bis-benzoxanethones emitters (S-/R-BN-tCz and S-/R-BN-PXZ), warm white CP-OLEDs were fabricated using solution-processed single emitting layer strategy. The successful realization of white CP-EL benefited from the same stable binaphthyl chirality and similar rigid structure of the two emissive CPL emitters. The devices exhibited the low turn-on voltage of ≈4.