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A pair of chiral aromatic-imide-based TADF emitters were conveniently constructed for the fabrication of highly efficient CP-OLEDs.

An electric field can drive electride-like superalkali Na(HCN)3Na (1) switches into superalkalides Na+(HCN)3Na− (2 and 3) via other superalkalides Na+(HCN)3Na− (2a and 3a) to form a SP4T NLO switch.

The superalkali electride e−⋯Li3+–PHY and superalkalide Liδ−–Li2(1–δ)−–PHY− show a good switchable effect.

Two novel chiral conjugated polymers

A novel actinobacterium, designated strain CRSS-Y-16

A strategy of chiral donor-acceptor copolymerization is proposed to develop chiral nonconjugated polymers with thermally activated delayed fluorescence (TADF). Based on this strategy, two pairs of chiral polymers ( R , R )-/( S , S )- pTpAcDPS and ( R , R )-/( S , S )- pTpAcBP were synthesized. The alternating copolymerization of the chiral donors and acceptors could effectively separate the frontier molecular orbitals, which made the polymers show small Δ E ST of 0.01-0.03 eV and efficient TADF properties. Moreover, the polymers also showed the quantum yield of up to 92% and the circularly polarized luminescence. The solution-processed circularly polarized organic light-emitting diodes showed circularly polarized electroluminescence signals with high external quantum efficiencies of up to 22.1% and maximum luminance of up to 34350 cd m -2 . This is the first report of CP-OLEDs based on chiral TADF polymer, which provides a useful and valuable guidance for the development of high-efficiency CPEL polymers.

A couple of fluorescent enantiomers, which are suitable for the emitters of high-efficiency TADF-sensitized CP-OLEDs, have been developed. The enantiomers show configurational stability, high PLQY of 98 %, large kr of 7.8×107 s-1 , and intense CPL activities with |glum | values of about 2.5×10-3 . Notably, by using matchable TADF sensitizer, the enantiomers were then exploited as emitter to fabricate CP-OLEDs. The TADF-sensitized CP-OLEDs not only show mirror-image CPEL activities with gEL values of +1.8×10-3 and -1.4×10-3 , but also display fast start-up featuring with low VT of 3.0 V as well as driving voltage of 4.8 V at 10 000 cd m-2 . Meaningfully, the TADF-sensitized fluorescent devices show high EQEmax of 21.5 % and extremely low efficiency roll-off, whose EQEs are 21.2 % and 15.3 % at 1000 and 10 000 cd m-2 , respectively. The obtained EQEs are comparable to those of CP-TADF emitters, which provides a promising perspective to break through the EL efficiency limit of CP-FL emitters.

A simple and green colorimetric sensing assay strategy for highly efficient determination of melamine has been fabricated, which is based on the redox reaction of gallic acid with Ag+. Monodispersed Ag nanoparticles (AgNPs) were obtained using gallic acid as a reducing and stabilizing agent. However, the aggregate behavior of AgNPs was observed, while the melamine was present in the reaction medium. As a result, the color of the solution changed from vivid yellow to brown, and the density of the color was quantitatively correlated with the melamine concentration. The aggregation of AgNPs could be attributable to the formation of hydrogen bonds between melamine and gallic acid. The designed sensor exhibited a good detection limit of 0.099 μM (0.012 ppm), which was much lower than the safety limit in China (1.0 ppm) and EU (2.0 ppm). Additionally, the sensing assay displayed good selectivity toward melamine over other coexisting substances. Consequently, the proposed colorimetric sensor was successfully used for the determination of melamine detection in raw milk samples.

Introduction Allergic fungal rhinosinusitis (AFRS) is characterized by refractory and high recurrence rate. Improper treatment may lead to repeated recurrence and even serious complications, including vision loss, blindness, and intracranial complications. However, AFRS is easy to be misdiagnosed clinically. Objective To ensure early diagnosis, the clinical presentations of patients with AFRS were studied. Methods Data from patients with sinusitis hospitalized in the First Affiliated Hospital of the University of Science and Technology of China (USTC) from January 2015 to October 2022 were collected. The patients were divided into three groups; group A patients with AFRS, group B patients suspected of AFRS, and group C patients with fungus ball sinusitis (FBS).We retrospectively analyzed the data using IBM SPSS 19.0 to perform the chi-square test and one-way ANOVA test. Results In total, 35 cases of AFRS, 91 cases of suspected AFRS, and 661 cases of FBS were rediagnosed. Compared with FBS patients, AFRS patients were younger, the total IgE, the percentage of eosinophils and basophils in peripheral blood were higher, and the proportion of patients with allergic rhinitis, asthma or hypo olfactory was higher. It had a higher recurrence rate. These results were also observed in the comparison between suspected AFRS patients and FBS patients, but no significant difference was found in the comparison between suspected AFRS patients and suspected AFRS patients. Conclusions and Significance AFRS may be misdiagnosed due to the low detection of fungi. To ensure early diagnosis, we recommend that patients with clinical, radiological, and laboratory features similar to those of AFRS but without evidence of fungal staining be treated according to the treatment criteria of AFRS.

The design and synthesis of nitrogen-doped aromatic belts with conjugated structures still remain a challenge. Here, we report the first nitrogen-doped aromatic belt with a [6]cycloparaphenylene skeleton, which is conveniently synthesized from the easily available calix[3]carbazole. The aromatic belt has a rigid conjugated structure and deep cavity, and it can encapsulate one dichloromethane both in solution and in the solid state. Interestingly, the aromatic belt shows strong green fluorescence with a quantum yield of 0.39 and exhibits a narrow HOMO-LUMO energy gap of 2.02 eV. The belt-shaped conjugated structure composed of three carbazole subunits has specific optoelectronic properties that will promote wide applications in supramolecular chemistry and materials science.

Three new emitters, namely 10,10'-(quinoline-2,8-diyl)bis(10H-phenoxazine) (Fene), 10,10'-(quinoline-2,8-diyl)bis(10H-phenothiazine) (Fens) and 10,10'-(quinoline-2,8-diyl)bis(9,9-dimethyl-9,10-dihydroacridine) (Yad), featuring quinoline as a new electron acceptor have been designed and conveniently synthesized. These emitters possessed small singlet–triplet splitting energy (ΔEst) and twisted structures, which not only endowed them show thermally activated delayed fluorescence (TADF) properties but also afforded a remarkable aggregation-induced emission (AIE) feature. Moreover, they also showed aggregation-induced delayed fluorescence (AIDF) property and good photoluminescence (PL) property, which are the ideal emitters for non-doped organic light-emitting diodes (OLEDs). Furthermore, high-performance non-doped OLEDs based on Fene, Fens and Yad were achieved, and excellent maximum external quantum efficiencies (EQEmax) of 14.9%, 13.1% and 17.4%, respectively, were obtained. It was also found that all devices exhibited relatively low turn-on voltages ranging from 3.0 V to 3.2 V probably due to their twisted conformation and the AIDF properties. These results demonstrated the quinoline-based emitters could have a promising application in non-doped OLEDs.

The exploration of innovative molecular switches has resulted in large developments in the field of molecular electronics. Focusing on a single molecular switch with different forms exhibiting different electride features, potassium-atom-doped all-cis 1,2,3,4,5,6-hexafluorocyclohexane K-F6C6H6 was studied theoretically. It was found that an oriented external electric field can drive excess electron transfer from the region outside of the K atom to that outside of F6C6H6. Subsequently, the electride-like molecule K-F6C6H6 (1) switches into the molecular electride K-F6C6H6⋯e− (3) through another electride-like molecule K-F6C6H6 (2). The static first hyperpolarizabilities (β0) are increased over 12- and 5-fold when moving from 1 to 2 and 3, respectively. The rise of each β0 value constitutes an order of magnitude improvement. Between them, the different β0 values suggest that K-F6C6H6 is a good candidate for use as a multiple-response nonlinear optics switch. The order of the β0 values of 1–4 for M-F6C6H6 (M = Li and Na) coincide with that of K-F6C6H6, also exhibiting a switch effect.

Exploration of novel molecular switches is an ongoing hot issue in molecular electronics. Alkalides and electrides are two typical representatives of excess electron compounds. It was found that M(HF)3M (M = Li or Na) induced by an oriented external electric field are good candidates for inorganic multi-response nonlinear optical (NLO) molecular switches. Their off forms (C3h) exhibit electride-like super alkali earth atom characteristics, while their on forms (C3v) exhibit charming superalkalide (M = Na or Li) or superalkali electride characteristics (M = Li). The increases of the static first hyperpolarizabilities (βe0) from off to on forms constitute a 2–3 orders of magnitude improvement for both M = Li and Na. These extremely large differences in βe0 reinforce the potential of M(HF)3M for applications in excellent multi-response nonlinear optical materials.

Triptycene derivatives, a type of specific aromatic compound, have been attracting much attention in many research areas. Over the past several years, triptycene and its derivatives have been described to be useful and efficient building blocks for the design and synthesis of novel supramolecular acceptors, porous materials and luminescent materials with specific structures and properties. In this review, recent researches on triptycene derivatives in supramolecular and materials chemistry are summarized. Especially, the construction of a new type of macrocyclic arenes and organic cages with triptycene and its derivatives as building blocks are focused on, and their applications in molecular recognition, self-assembly and gas selective sorption are highlighted. Moreover, the applications of triptycene and its derivatives in porous organic materials and thermally activated delayed fluorescence (TADF) materials are also discussed.

The thermally activated delayed fluorescence (TADF) materials with aggregation-induced emission (AIE) properties have attracted increasing interest for their applications as the emitters in non-doped organic light-emitting diodes (OLEDs). In this work, three quinoline-based TADF molecules 9,9-dimethyl-10-(quinolin-2-yl)-9,10-dihydroacridine (DMAC-QL), 10-(quinolin-2-yl)-10H-phenoxazine (PXZ-QL) and 10-(quinolin-2-yl)-10H-phenothiazine (PTZ-QL) were conveniently synthesized by a one-step reaction starting from commercially available materials. The twisted conformation was confirmed by single crystal analysis, and all the compounds exhibited high thermal stability. Moreover, the ΔEST values of DMAC-QL, PXZ-QL and PTZ-QL were 0.06, 0.10 and 0.04 eV, and their delay lifetimes were 2.15, 1.86 and 15.76 μs, respectively, indicating their excellent TADF properties. They also exhibited typical AIE and aggregation-induced delayed fluorescence (AIDF) properties in THF/H2O solution. The non-doped OLEDs based on the emitters DMAC-QL, PXZ-QL and PTZ-QL were fabricated, and the maximal EQEs of the devices were 7.7, 17.3 and 14.8%, respectively, along with turn-on voltages of 3.2, 2.6 and 2.8 eV. It was further found that the efficiency roll-off of the non-doped device based on PXZ-QL was very small due to its short delay lifetime and excellent AIE and AIDF properties.

Planar chiral organic fluorescent materials that exhibit high chiral stability, high efficiency and circularly polarized luminescence (CPL) concurrently remain an unresolved issue despite their promising applications in optical encryption and 3D-display. Herein, a pair of new donor-chiral π-acceptor (D-π*-A) type planar chiral thermally activated delayed fluorescence (TADF) enantiomers, namely R/S-PXZ-PT, are developed. Such D-π*-A type structure completely suppresses the racemization of the planar chirality, making it possible to prepare circularly polarized organic light-emitting diodes (CP-OLEDs) through vacuum-deposited processing. Moreover, this design perfectly integrates the chiral unit into the luminescent unit to achieve intence CPL activity with luminescence asymmetry factors (glum) of ±1.9×10-3. Notably, the enantiomer-based devices exhibit yellow emission with maximum external quantum efficiency (EQE) of 20.1%, and mirror-image circularly polarized electroluminescence signals with electroluminescence dissymmetry factors (gEL) of +1.8×10−3/−1.3×10−3. This work not only enriches the diversity in chiral TADF molecular design, but also provides a new perspective for the development of high-efficiency CP-OLEDs with stable planar chiral TADF materials.

A new strategy of thermally activated delayed fluorescence (TADF) material-sensitized circularly polarized luminescence (CPL) has been proposed for improving the efficiencies of fluorescent circularly polarized organic light-emitting diodes (OLEDs) (CP-OLEDs). Consequently, a pair of helicene enantiomers, (P)-HAI and (M)-HAI, were synthesized. The helicene enantiomers with the rigid helical π-skeleton had highly thermal and enantiomeric stabilities, and they also showed excellent photophysical properties, especially, intense mirror-image CPL activities with large luminescence dissymmetry factor (|glum|) values of about 6 × 10−3. Notably, the CP-OLEDs with the helicene enantiomers as emitters and a TADF molecule as sensitizer not only displayed better performance of lower turn-on voltage (VT) of 2.6 V, four-fold maxmium-external quantum efficiency (EQEmax) of 5.3%, and lower efficiencies roll-off of 1.9% at 1000 cd m−2, than those of the devices without TADF sensitizer, but also exhibited intense circularly polarized electroluminescence (CPEL) with the electroluminescence dissymmetry factor (gEL) values of −2.3 × 10−3 and +3.0 × 10−3. Meanwhile, this study also represents the first thermally activated sensitized fluorescent CP-OLEDs with markedly enhanced efficiencies and intense CPEL.

A novel Cu(II) compound [CuL2]·2H2O was synthesized by hydrothermal methods, and its crystal structure was determined by single-crystal X-ray diffraction. The title compound crystallized in the monoclinic space group P21/c as an isolated monocyte structure. The strong π…π stacking and hydrogen bonding interactions produce one-dimensional (1D) chains. A series of properties of the title compound were tested by solid state photoluminescence, CIE analysis and solid-state diffuse reflectance. The results show that the compound is a blue light emitter, CIE (0.1291, 0.0783) and has an energy bandwidth of 1.65 eV. Time-dependent density functional theory (TDDFT) calculation results show that the emission of the compound can be attributed to charge transfer from metal to ligand and ligand to ligand (MLCT and LLCT). A novel Cu (II) complex is synthesized via hydrothermal preparation, which is characteristic of an isolated structure, at the same time, it displays a narrow and intense photoluminescence emission band in the blue region and theoretical study reveals that the photoluminescence emission is originated from the metal-to-ligand and ligand-to-ligand charge transfer transition.

A novel cadmium compound [CdL(bipy)2]·6H2O was synthesized by hydrothermal method, and its crystal structure was determined by single-crystal X-ray diffraction. The title compound crystallized in t...

The use of a chiral, emitting skeleton for axially chiral enantiomers showing activity in thermally activated delayed fluorescence (TADF) with circularly polarized electroluminescence (CPEL) is proposed. A pair of chiral stable enantiomers, (-)-(S)-Cz-Ax-CN and (+)-(R)-Cz-Ax-CN, was designed and synthesized. The enantiomers, both exhibiting intramolecular π-conjugated charge transfer (CT) and spatial CT, show TADF activities with a small singlet-triplet energy difference (ΔEST ) of 0.029 eV and mirror-image circularly polarized luminescence (CPL) activities with large glum values. Notably, CP-OLEDs based on the enantiomers feature blue electroluminescence centered at 468 nm with external quantum efficiencies (EQEs) of 12.5 and 12.7 %, and also show intense CPEL with gEL values of -1.2×10-2 and +1.4×10-2 , respectively. These are the first CP-OLEDs based on TADF-active enantiomers with efficient blue CPEL.

MoO3 has gained a great deal of attention as a promising electrode material in energy storage devices. In particular, the low dimensional MoO3 nanosheets coated with carbon layers are desirable electrode materials in supercapacitors. However, the fabrication or construction of β-MoO3 with a special morphology is difficult. Here, we report a simple solvothermal treatment method to synthesize two-dimensional β-MoO3@C (2D β-MoO3@C) nanosheets. When used as electrode materials for supercapacitors, the as-prepared material displays an ultra-long lifespan with a 94% retention ratio after 50 000 cycles at 2 A g−1. The excellent cycling stability is mainly attributed to the unique 2D nanosheet structure and the presence of the carbon layer on the surface of the nanosheet. Specifically, the presence of the carbon layer increases the electric conductivity of MoO3, which facilitates a good access point for electrolyte ions and short ion diffusion paths. In addition, MoO3 that has been coated with a carbon layer can maintain a good structural stability due to the carbon layer restricting the volume expansion of MoO3 during the charge procedure. We believe that the present work opens a new way for designing the 2D layered materials with unique architectures for supercapacitor applications.

Purely organic TADF emitters have been rapidly developed in recent years and their TADF has become one of the most promising achievement towards highly efficient OLEDs. Apart from the advantages such as stable structure, low-cost and high internal quantum efficiency of these emitters that have been found, the demand for high colour purity has become a new challenge. There have been many reports that show possibilities of designing narrowband TADF emitters using totally different methods. Recently, TADF emitters have exhibited a narrow emission with a FWHM of below 20 nm. Therefore, broad emission spectra and bad colour purity shall not always be considered as fatal defects of TADF emitters. Herein, a review of narrowband TADF emitters is presented with a focus on the molecular design, photophysical properties and performance of the corresponding OLED devices. Besides, this review will exhibit the common characteristics of emitters for the purpose of further designs.

A novel intra-molecular self-redox switch, Li3N3Mg, is constructed theoretically. Our investigation showed that a suitably oriented external electric field (OEEF) can drive a long-range excess electron transfer from Mg atoms to Li3 rings. And subsequently, an interesting intra-molecular self-redox from Li32+N33−Mg+ to Li3+N33−Mg2+ accompanying the large different electronic static first hyperpolarizability (βe0) is exhibited. The increase of the βe0 value constitutes an order of magnitude improvement from Li32+N33−Mg+ (34 986 a.u.) to Li3+N33−Mg2+ (101 225 a.u.), which indicates that Li3N3Mg is a good candidate for a self-redox NLO molecular switch.

A novel copper complex [CuL(bipy)(H2O)]·H2O was synthesized by solvothermal reaction and its crystal structure was determined by single-crystal X-ray diffraction technique. (HL = 3-hydroxy-2-methylquinoline4-carboxylic acid; bipy = 2,2′-bipyrdine) The title complex (1) crystallizes in the orthorhombic system of the Pbca space group, and exists as an isolated mononuclear structure. The intermolecular hydrogen bonds and the strong π···π stacking interactions yield a three-dimensional (3-D) supramolecular network. Solid-state photoluminescence spectrum uncovers that it shows an emission in the pale blue region of the light spectrum. It has remarkable CIE (Commission Internationale de I’Eclairage) chromaticity coordinates of (0.2656, 0.3162), so it may be a very promising color lighting and display converter. Time-dependent density functional theory (TDDFT) calculation reveals that this emission is caused by to the ligand-to-ligand charge transfer (LLCT). Solid-state diffuse reflectance data shows that there is a narrow optical band gap of 1.38 eV. Therefore, it could be probably a candidate for narrow band gap semiconductors. A novel copper (II) complex is synthesized via solvothermal reactions, which is characteristic of an isolated structure, at the same time, it displays a wide and intense photoluminescence emission band in the pale blue region and theoretical study reveals that the photoluminescence emission is originated from the ligand-to-ligand charge transfer transition.

For Li@AR (AR = benzene and naphthalene), it is reported that hopping of Li atom under the external electric field between electride and lithium salt configurations brings decidedly different charg...

Alkalides with large nonlinear optical (NLO) responses exhibit broad applications in the electro-optical device field. In the present work, based on alkali (Li and Na) in conjunction with alkaline-...

The construction of new and efficient chiral TADF materials with red emission and the exploration of their applications in OLED devices still remain a great challenge for the difficulty in molecular design and low efficiency of devices. In this work, we synthesized a couple of 1,8-naphthalimide-based enantiomers (−)-(R,R)-CAI-DMAC and (+)-(S,S)-CAI-DMAC. The enantiomers not only exhibit high thermal stability with decomposition temperature of 405 °C, excellent electrochemical properties, and good thermally activated delayed fluorescence (TADF) properties with small ΔEST of 0.07 eV, but also show obvious mirror-image circular dichroism and circularly polarized luminescence properties. Moreover, by using (−)-(R,R)-CAI-DMAC and (+)-(S,S)-CAI-DMAC as emitters, the OLEDs with the bands both centred at 592 nm achieved high maximum external quantum efficiency of 12.4% and 12.3%, respectively.

Three new 1,8-naphthyridine-based thermally activated delayed fluorescence (TADF) emitters, 2,7-di(9,9-dimethylacridin-10(9H)-yl)-1,8-naphthyridine (DMAC-ND), 2,7-di(10H-phenothiazin-10-yl)-1,8-naphthyridine (PTZ-ND) and 2,7-di(10H-phenoxazin-10-yl)-1,8-naphthyridine (PXZ-ND), were designed and synthesized. They possessed twisted structures and small ΔEST, which could make them show excellent TADF and AIDF properties. Consequently, multi-color organic light-emitting diodes (OLED) based on emitters DMAC-ND, PTZ-ND and PXZ-ND were fabricated, which could achieve a maximum external quantum efficiency (EQE) of 14.1, 13.4 and 13.0%, respectively. Moreover, all devices exhibited relatively low turn-on voltages and low efficiency roll-off ranging from 4.5% to 20% at the luminance of 1000 cd m−2 probably owing to the microsecond-scale delayed photoluminescence (PL) and AIDF properties of the emitters. Notably, a DMAC-ND-based non-doped device reached the luminance of 20 000 cd m−2 easily at the voltage of 6.5 V, and exhibited very low efficiency roll-off of 4.5% at the luminance of 1000 cd m−2 and 33.6% at the luminance of 10 000 cd m−2.

Phthalimide-based "D-N-A" emitters o-AI-Cz, m-AI-Cz and p-AI-Cz showed TADF and RTP properties due to their small ΔEST in both film and crystalline states. In particular, o-AI-Cz exhibited an ultralong RTP with a lifetime of 602 ms in air and remarkable afterglow, which could allow it to be used as a security ink for application in anti-counterfeiting materials. Moreover, o-AI-Cz showed intense intramolecular interaction between the donor and the acceptor subunits, while p-AI-Cz could form regular hexagonal pores with a diameter of 13.171 Å in the solid state, which might result in their different RTP properties.

MoS2 is regarded as one of the cost-effective materials for many important applications. In this work, we report a simple one-step hydrothermal method for the directed synthesis of a rosette-like MoS2 nanoflower modified electrode without using adhesion agents. Interestingly, owing to the hierarchical structures, the as-prepared MoS2-based electrode exhibits significantly enhanced performance for both the hydrogen evolution reaction in acidic environments and supercapacitors. When used in the hydrogen evolution reaction, the electrode shows a low overpotential of ∼0.25 V at 10 mA cm−2, a Tafel slope of ∼71.2 mV per decade, and long-term durability over 20 h of hydrogen evolution reaction operation at 10 mV cm−2. In addition, as a supercapacitor electrode, it exhibits a good capacity of 137 mF cm−2 at a current density of 10 mA cm−2 and excellent stability in 1 M H2SO4 at a scan rate of 50 mV s−1. The outstanding performances of the as-prepared materials may be ascribed to the unique 3D architectures of the rosette-like MoS2 nanoflowers. This work could provide a strategy to explore low-cost and highly efficient electrocatalysts with desired nanostructures for the hydrogen evolution reaction and supercapacitors applications.

Using nitronyl nitroxide radicals, we presented a comparative study of magneto-structural correlations between series of CuI and AgI models (Cu(a) ∼ Cu(d) and Ag(a) ∼ Ag(d), modified from [CuI(immepy)2]PF6 and [AgI(impy)2]PF6 (Oshio et al., 1997). Cu(a) ∼ Cu(d) possess three characteristics that are significantly different from Ag(a) ∼ Ag(d) for the more utilization of CuI than that of AgI in the ferromagnetic joints of radical networks. (1) Structural shorter Cu-N length in Cu(a) ∼ Cu(d) than corresponding Ag-N length in Ag(a) ∼ Ag(d) leads to the quite larger Wiberg bond index (WBI), ∇2ρ(r) values, and metal atomic spin densities between triplet (T) and broken-symmetry (BS) states (ΔρT-BS) of the former than that of the latter. (2) From each of AgI (Ag(a) ∼ Ag(d)) to the corresponding one of CuI (Cu(a) ∼ Cu(d)), the spin density increases up to one or two order of magnitudes, which indicates the more notable spin delocalization from ONCN groups (paramagnetic centers) to CuI than that to AgI. Changing the dihedral angle (θ) between two radical components, the variation of the magnetic coupling constants (Jab) is directly proportional to the spin density of CuI but inversely proportional to that of one ONCN group. (3) Due to the larger d orbital distributions of CuI than that of AgI in the SOMOs, large metal-ligand charge transfer (MLCT) occurs in Cu(a) ∼ Cu(d) but little in Ag(a) ∼ Ag(d). The broken orthogonality is not evidently associated with the significantly different magnetic coupling interactions between CuI and AgI models.

The exploration of innovative molecular switches has resulted in large developments in the field of molecular electronics. Focusing on a single molecular switch with different forms exhibiting different electride features, potassium-atom-doped all-cis 1,2,3,4,5,6-hexafluorocyclohexane K-F6C6H6 was studied theoretically. It was found that an oriented external electric field can drive excess electron transfer from the region outside of the K atom to that outside of F6C6H6. Subsequently, the electride-like molecule K-F6C6H6 (1) switches into the molecular electride K-F6C6H6e- (3) through another electride-like molecule K-F6C6H6 (2). The static first hyperpolarizabilities (β0) are increased over 12- and 5-fold when moving from 1 to 2 and 3, respectively. The rise of each β0 value constitutes an order of magnitude improvement. Between them, the different β0 values suggest that K-F6C6H6 is a good candidate for use as a multiple-response nonlinear optics switch. The order of the β0 values of 1-4 for M-F6C6H6 (M = Li and Na) coincide with that of K-F6C6H6, also exhibiting a switch effect.

By doping two potassium atoms among three CF cages, peanut-shaped single molecular solvated dielectron (CF)&K was theoretically presented. The triplet structures with two excess electrons individually inside left and middle cages (isomers I or II) are thermodynamically more stable than both open-shell (OS) and close-shell (CS) singlet ones with lone pair of excess electrons inside middle cage. Applying an oriented external electric field (OEEF) of -20 × 10 au (-0.1018 V/Å) or a larger one can result in both left-to-right transfers of the two excess electrons, and then releasing the OEEF can form new kind of inter-cage electron-transfer isomers (III or IV). Each triplet I ~ IV with three redox sits may be new members of mixed-valent compounds, namely, Robin-Day Class II. For electrified I of (CF)&K , the following spin states are ground state: 1) triplet state in field ranges of -120 × 10 < F < -30 × 10 au and 30 × 10 < F < 111 × 10 au; 2) CS singlet state in range of F ≥ 111 × 10 and ≤ -120 × 10 au; 3) OS singlet state in ranges of -30 × 10 ≤ F ≤ -5 × 10 au and 5 × 10 ≤ F ≤ 30 × 10 au.

For the stable superalkali-alkalide ion pairs in alkalide solutions, a DFT study was performed to investigate the nonlinear optics (NLO) responses of δ +(M-HMHC)-M’ δ - (M, M’ = Li, Na and K). The NLO responses display obvious alkali metal atomic number dependence (M’). From δ +(M-HMHC)-Li δ - to δ +(M-HMHC)-K δ -, the increases of the static and dynamic first hyperpolarizabilities constitute a 1 ∼ 3 orders of magnitude improvement.

A novel intra-molecular self-redox switch, Li

An axially chiral TADF emitter, 4tBuCzPN, with a dual emitting core was easily synthesized. Compared with the TADF emitter 2tBuCzPN with the PLQY of 29% and EQE of 5.3%, 4tBuCzPN showed a significantly increased PLQY (74%) and EQE (20.8%) for its OLED. Moreover, the enantiomers of 4tBuCzPN also exhibited mirror-image CD and CPL properties, and the glum values of (+)-4tBuCzPN and (−)-4tBuCzPN were +5.4 × 10−3 and −5.0 × 10−3 in toluene, respectively.

Focusing on innovative high-performance single-pole double-throw nonlinear optical (NLO) molecular switches, two C3v configurations (1 and 3) and one D3h configuration (2) of bipyramidal CaN3Ca have been obtained by using quantum mechanical methods. Not only are 1, 2, and 3 alkaline-earth-based aromatic superalkalis, but they are also interesting electrides. The salt-like electronic structures of e-Ca2+N33-Ca2+ (1) and Ca2+N33-Ca2+e- (3) with localized redox centres are rare inorganic Robin-Day class II-type structures, and e0.5-Ca2+N33-Ca2+e0.5- (2) with a delocalized structure is a class III-type mixed-valent superalkali electride. Under a small external electric field of ±0.0110 a.u. (0.565 V Å-1), the short-distance hopping of Ca atoms in CaN3Ca from the D3h configuration with in-plane aromaticity to each C3v configuration with out-of-plane aromaticity brings about the long-range transfer of half an electron from one Ca atom to another. And, subsequently, a large dipole moment (μ0) and remarkable static first hyperpolarizability (β0) occur. μz and βzzz range from 0 (D3h, off form) to -12.1 or 12.1 D (C3v, on forms) and from 0 (D3h, off form) to -19 428 or 19 428 a.u. (C3v, on forms), respectively. These extremely large differences in μz and βzzz values between the D3h and each of the C3v configurations confirm the potential of these inorganic aromatic Robin-Day-type superalkali electrides for applications in high-sensitivity multi-state nonlinear optical switches.