Boron‐ and Oxygen‐Doped π‐Extended Helical Nanographene with Circularly Polarised Thermally Activated Delayed Fluorescence

Abstract

Helical nanographenes have garnered substantial attention owing to their finely adjustable optical and semiconducting properties. The strategic integration of both helicity and heteroatoms into the nanographene structure, facilitated by a boron‐oxygen‐based multiple resonance (MR) thermally activated delayed fluorescence (TADF), elevates its photophysical and chiroptical features. This signifies the introduction of an elegant category of helical nanographene that combines optical (TADF) and chiroptical (CPL) features. In this direction, we report the synthesis, optical, and chiroptical properties of boron, oxygen‐doped ᴨ‐extended helical nanographene. The π‐extension induces distortion in the DOBNA‐incorporated nanographene, endowing a pair of helicenes, (P)‐B2NG, and (M)‐B2NG exhibiting circularly polarized luminescence with glum of ‐2.3 × 10−3 and +2.5 × 10−3, respectively. B2NG exhibited MR‐TADF with a lifetime below 5 μs, and a reasonably high fluorescence quantum yield (50%). Our molecular design enriches the optical and chiroptical properties of nanographenes and opens up new opportunities in multidisciplinary fields.

Solvent-Free Organic Liquids: An Efficient Fluid Matrix for Unexplored Functional Hybrid Materials

“…56,57 TADF materials often suffer from severe aggregation-induced quenching (AIQ) due to strong π−π stacking. 58 Given the difficult nature of molecular packing in the crystal state, blocking multiple AIQ channels is key. And limitations of existing crystalline luminescent materials such as solubility, self-healing properties, etc., are making challenges for existing organic materials.…”

“…Interest in organic luminescent materials exhibiting TADF materials has increased tremendously in the past few years due to their longer lifetime than conventional fluorescent materials. − Besides, small singlet–triplet energy gap (Δ E ST ) of these materials facilitates reverse intersystem crossing from triplet to singlet state and thereby leads to 100% internal quantum yield in the electroluminescence process. , TADF materials often suffer from severe aggregation-induced quenching (AIQ) due to strong π–π stacking . Given the difficult nature of molecular packing in the crystal state, blocking multiple AIQ channels is key.…”