Multi-resonance induced by boron and nitrogen atoms in opposite resonance positions endows a thermally activated delayed fluorescence (MR-TADF) emitter with a strikingly small full width at half maximum of only 26 nm and excellent photoluminescence quantum yield of up to 97.48 %. The introduction of a carbazole unit in the para position of the B-substituted phenyl-ring can significantly boost up the resonance effect without compromising the color fidelity, subsequently enhancing the performances of the corresponding pure blue TADF-OLED, with an outstanding external quantum efficiency (EQE) up to 32.1 % and low efficiency roll-off, making it one of the best TADF-OLEDs in the blue region to date. Furthermore, utilizing this material as host for a yellow phosphorescent emitter, the device also shows a significantly reduced turn-on voltage of 3.2 V and an EQE of 22.2 %.

Materials with circularly polarized luminescence (CPL) activity have immense potential applications in molecular switches, optical sensors, information storage, asymmetric photosynthesis, 3D optical displays, biological probe, and spintronic devices. However, the achiral architectures of most of the luminophores severely limit their practical needs. Within this context, molecular ferroelectrics with striking chemical variability and structure–property flexibility bring light to the assembly of CPL-active ferroelectric materials. Herein, we report organic–inorganic perovskite enantiomorphic ferroelectrics, (R)- and (S)-3-(fluoro­pyrrol­idinium)­MnBr3, undergoing a 222F2-type ferroelectric phase transition at 273 K. Their mirror relationships are verified by both single-crystal X-ray diffraction and vibrational circular dichroism (VCD). Furthermore, the corresponding Cotton effect for two chiral crystals was captured by mirror CPL activity. This may be assigned to the inducing interaction between the achiral luminescent perovskite framework and chiral organic components. As far as we know, this is the first molecular ferroelectric with CPL activity. Accordingly, this will inspire intriguing research in molecular ferroelectrics with CPL activity and holds great potential for the development of new optoelectronic devices.

This work describes a strategy to produce circularly polarized thermally activated delayed fluorescence (CP-TADF). A set of two structurally similar organic emitters SFST and SFOT are constructed, whose spiro architectures containing asymmetric donors result in chirality. Upon grafting within the spiro frameworks, the donor and acceptor are fixed proximally in a face-to-face manner. This orientation allows intramolecular through-space charge transfer (TSCT) to occur in both emitters, leading to TADF properties. The donor units in SFST and SFOT have a sulfur and oxygen atom, respectively; such a subtle difference has great impacts on their photophysical, chiroptical, and electroluminescence (EL) properties. SFOT exhibits greatly enhanced EL performance in doped organic light-emitting diodes, with external quantum efficiency (EQE) up to 23.1%, owing to the concurrent manipulation of highly photoluminescent quantum efficiency (PLQY, ∼90%) and high exciton utilization. As a comparison, the relatively larger sulfur atom in SFST introduces heavy atom effects and leads to distortion of the molecular backbone that lengthens the donor–acceptor distance. SFST thus has lower PLQY and faster nonradiative decay rate. The collective consequence is that the EQE value of SFST, i.e., 12.5%, is much lower than that of SFOT. The chirality of these two spiro emitters results in circularly polarized luminescence. Because SFST has a more distorted molecular architecture than SFOT, the luminescence dissymmetry factor (|g lum|) of circularly polarized luminescence of one enantiomer of the former, namely, either (S)-SFST or (R)-SFST, is almost twice that of (S)-SFOT/(R)-SFOT. Moreover, the CP organic light-emitting diodes (CP-OLEDs) show obvious circularly polarized electroluminescence (CPEL) signals with g EL of 1.30 × 10–3 and 1.0 × 10–3 for (S)-SFST and (S)-SFOT, respectively.

Circularly polarized organic light‐emitting diodes (CP‐OLEDs) are particularly favorable for the direct generation of CP light, and they demonstrate a promising application in 3D display. However, up to now, such CP devices have suffered from low brightness, insufficient efficiency, and serious efficiency roll‐off. In this study, a pair of octahydro‐binaphthol (OBN)‐based chiral emitting enantiomers, (R/S)‐OBN‐Cz, are developed by ingeniously merging a chiral source and a luminophore skeleton. These chirality–acceptor–donor (C–A–D)‐type and rod‐like compounds concurrently generate thermally activated delayed fluorescence with a small ΔEST of 0.037 eV, as well as a high photoluminescence quantum yield of 92% and intense circularly polarized photoluminescence with dissymmetry factors (|gPL|) of ≈2.0 × 10−3 in thin films. The CP‐OLEDs based on (R/S)‐OBN‐Cz enantiomers not only display obvious circularly polarized electroluminescence signals with a |gEL| of ≈2.0 × 10−3, but also exhibit superior efficiencies with maximum external quantum efficiency (EQEmax) up to 32.6% and extremely low efficiency roll‐off with an EQE of 30.6% at 5000 cd m−2, which are the best performances among the reported CP devices to date.

This work describes a nickel-catalyzed Ullmann-type thiolation of aryl iodidesunder mild electrochemical conditions. The simple undivided cell with graphene/nickel foam electrode setups offers excellent substrate tolerance, affording aryl and alkyl sulfides in good chemical yields. Furthermore, the mechanism for this electrochemical cross-coupling reaction has been investigated by cyclic voltammetry.

Pure organic materials with intrinsic room‐temperature phosphorescence typically rely on heavy atoms or heteroatoms. Two different strategies towards constructing organic room‐temperature phosphorescence (RTP) species based upon the through‐space charge transfer (TSCT) unit of [2.2]paracyclophane (PCP) were demonstrated. Materials with bromine atoms, PCP‐BrCz and PPCP‐BrCz, exhibit RTP lifetime of around 100 ms. Modulating the PCP core with non‐halogen‐containing electron‐withdrawing units, PCP‐TNTCz and PCP‐PyCNCz, successfully elongate the RTP lifetime to 313.59 and 528.00 ms, respectively, the afterglow of which is visible for several seconds under ambient conditions. The PCP‐TNTCz and PCP‐PyCNCz enantiomers display excellent circular polarized luminescence with dissymmetry factors as high as −1.2×10−2 in toluene solutions, and decent RTP lifetime of around 300 ms for PCP‐TNTCz enantiomers in crystalline state.

Chiral materials with circularly polarized luminescence (CPL) are potentially applicable for 3D displays. In this study, by decorating the pyridinyl‐helicene ligands with ‐CF3 and ‐F groups, the platinahelicene enantiomers featured superior configurational stability, as well as high sublimation yield (>90 %) and clear CPPL properties, with dissymmetry factors (|gPL|) of approximately 3.7×10−3 in solution and about 4.1×10−3 in doped film. The evaporated circularly polarized phosphorescent organic light‐emitting diodes (CP‐PhOLEDs) with two enantiomers as emitters exhibited symmetric CPEL signals with |gEL| of (1.1–1.6)×10−3 and decent device performances, achieving a maximum brightness of 11 590 cd m−2, a maximum external quantum efficiency up to 18.81 %, which are the highest values among the reported devices based on chiral phosphorescent PtII complexes. To suppress the effect of reverse CPEL signal from the cathode reflection, the further implementation of semitransparent aluminum/silver cathode successfully boosts up the |gEL| by over three times to 5.1×10−3.

In recent years, two-dimensional (2D) black phosphorus (BP) has been widely applied in many fields, such as (opto)electronics, transistors, catalysis and biomedical applications due to its large surface area, tunable...