A novel π-stacked polymer based on a pseudo–meta–linked [2.2]paracyclophane moieties was synthesized by Sonogashira-Hagihara coupling. The UV-vis absorption spectra of the synthesized polymer and model compounds revealed an extension of the conjugation length owing to the through-space conjugation. The optical properties of the π-stacked dimer with the pseudo–meta–linked [2.2]paracyclophane unit were compared with those of the corresponding dimers with the pseudo–ortho– and pseudo–para–linked [2.2]paracyclophane units.

Organic light‐emitting diodes (OLEDs) receive considerable attention because of their commercial use in flat panel displays. Herein, highly efficient spiroborate‐based host materials are reported for use in blue OLEDs. Our designed spiroborates (SBOX) were simple to synthesize and exhibited high triplet excitation energies, narrow S‐T gaps, and balanced charge carrier mobilities. A blue OLED containing one of the designed spiroborates, SBON, as a host exhibited a high external quantum efficiency (27.6 %) and low turn‐on voltage (3.7 V) compared to those observed using 3,3′‐di(9H‐carbazol‐9‐yl)‐1,1′‐biphenyl (17.6 % and 4.5 V, respectively), indicating their potential as host materials in OLEDs.

Figure 4. a) Energy diagram of the OLED materials (eV). The emitting layer comprises 1 wt % of the emitting material (ν-DABNA) and 99 wt % of the host material (SBON, SBON-Me, or mCBP). b) Normalized EL spectra of the OLEDs containing SBON (blue line), SBON-Me (red line), or mCBP (green line) as the host material. c) CIE (x, y) coordinates observed using the SBON device. d) Current density (solid) and luminance (dashed) as functions of driving voltage. e) EQE and f) power efficiency as functions of luminance.

Organic Electronics. Spiroborate‐based host materials with high triplet energies and ambipolar charge‐transport properties are reported by Takuji Hatakeyama et al. in their Communication (e202217512).

Organic Electronics. Spiroborate‐based host materials with high triplet energies and ambipolar charge‐transport properties are reported by Takuji Hatakeyama et al. in their Communication (e202217512).