Purely organic TADF emitters have rapidly developed in recent years and TADF has become one of the most promising achievement for highly efficient OLEDs. Apart from the advantages such as...

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.

A new kind of solvated electron systems, sphere-shaped e(-)@C60F60 (I(h)) and capsule-shaped e(-)@C60F60 (D6h), in contrast to the endohedral complex M@C60, is represented at the B3LYP/6-31G(d) + dBF (diffusive basis functions) density functional theory. It is proven, by examining the singly occupied molecular orbital (SOMO) and the spin density map of e(-)@C60F60, that the excess electron is indeed encapsulated inside the C60F60 cage. The shape of the electron cloud in SOMO matches with the shape of C60F60 cage. These cage-like single molecular solvated electrons have considerably large vertical electron detachment energies VDE of 4.95 (I(h)) and 4.67 eV (D6h) at B3LYP/6-31+G(3df) + dBF level compared to the VDE of 3.2 eV for an electron in bulk water (Coe et al., Int Rev Phys Chem 2001, 20, 33) and that of 3.66 eV for e(-)@C20F20 (Irikura, J Phys Chem A 2008, 112, 983), which shows their higher stability. The VDE of the sphere-shaped e(-)@C60F60 (I(h)) is greater than that of the capsule-shaped e(-)@C60F60 (D6h), indicating that the excess electron prefers to reside in the cage with the higher symmetry to form the more stable solvated electron. It is also noticed that the cage size [7.994 (I(h)), 5.714 and 9.978 A (D6h) in diameter] is much larger than that (2.826 A) of (H2O)20- dodecahedral cluster (Khan, Chem Phys Lett 2005, 401, 85).

Isomer structures of four endohedral fullerene dimers Na@C 60 C 60 @F with an n-fold bond (n ) 1, 2, 5 and 6) are obtained for the first time by using density functional theory. The n-fold bond depends on the dimeric pattern between endohedral fullerenes Na@C 60 and F@C 60 . The pattern includes point-point (n ) 1), side-side (n ) 2), and face-face (n ) 5, 6) mode. The four structures [1 + 1], [2 + 2], [5 + 5] and [6 + 6] have larger n-fold bond energies, as compared to that of the neutral π-(C 60 ) 2 dimer. In addition, the electronic properties of the endohedral dimers are first investigated. The dimers exhibit a strong nonlinear optical (NLO) response: large static first hyperpolarizabilities. Moreover, the first hyperpolarizability depends on the dimeric pattern. The large first hyperpolarizabilitiy is up to 25 169 au for [5 + 5], which is almost 110 times larger than that of the NaF molecule (228 au). The great enhancement of the first hyperpolarizability relates to the geometric effect of expanding the Na · · · F distance from 1.980 for NaF to 6.355 Å for [5 + 5], which provides a novel strategy for enhancing the first hyperpolarizability by altering the molecular structure. It is also found that the crucial charge transfer transition depends on the dimeric pattern, and controlling the transition may be performed by modulating the dimeric pattern. This work may promote the study of new nanomaterials, including highperformance NLO materials, and enrich knowledge of chemical bonds (for example, multifold bond between cages) and long-range interaction between two trapped atoms in different cages.