02427nas a2200277   4500008004100000022001400041245012800055210007000183260000900253490000700262520147600269653003801745653001001783653001801793653001701811653000901828100002201837700001801859700003001877700002401907700002001931700002001951700001801971700003001989856013002019       2024                        eng d  a0947-653900aBoron- and oxygen-doped π-extended helical nanographene with circularly polarised thermally activated delayed fluorescence0 aBoron and oxygendoped πextended helical nanographene with circul  cAPR 0 v303 a<p>
	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 pi-extended helical nanographene. The pi-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 -2.3x10-3 and +2.5x10-3, respectively. B2NG exhibited MR-TADF with a lifetime below 5 mu s, 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. B, O-doped pi-extended helical nanographene has been explored for its optical and chiroptical properties. The presence of helical and nanographene segments stabilize the helicity and imparts tunable optical properties. Helical nanographene display circularly polarized thermally activated delayed fluorescence. image</p>
10acircularly polarized luminescence10aDOBNA10adual emission10ananographene10aTADF1 aVenugopal, Geethu1 aKumar, Viksit1 aJadhav, Ashok, Badrinaray1 aDongre, Sangram, D.1 aKhan, Abujunaid1 aGonnade, Rajesh1 aKumar, Jatish1 aBabu, Sukumaran, Santhosh  uhttps://library.ncl.res.in/content/boron-and-oxygen-doped-%CF%80-extended-helical-nanographene-circularly-polarised-thermally02407nas a2200313   4500008004100000245008500041210007000126260000800196300001500204490000700219520144500226653001401671653000801685653001401693653001701707653002001724653000901744100001801753700002201771700003001793700002401823700002001847700001801867700001901885700001901904700002101923700003001944856011901974       2025                        eng d00aRegioisomeric π-extended nanographene with long-lived phosphorescence afterglow0 aRegioisomeric πextended nanographene with longlived phosphoresce  cFEB  ae2024221250 v643 a<p>
	The cutouts of graphene sheets, particularly those with a nonplanar topology, present vast opportunities for advancement. Even a slight deviation from the planar structure can lead to intriguing (chiro)optical features for helically twisted nanographenes. In this context, we introduce two regioisomeric pi-extended nanographenes that exhibit distinct excited-state characteristics. The helicene structure and the photophysical features can be easily tuned by changing the connecting position of the nanographene to the carbazole core (2,7- and 3,6-). Single-crystal X-ray diffraction analysis confirmed the formation of nanographenes with bent and helical conformations. Both derivatives exhibited thermally activated delayed fluorescence at room temperature and phosphorescence at low temperatures. Notably, the nanographene with the bent structure displayed an impressive red afterglow lasting over 30seconds, in contrast to the very weak afterglow observed in the helical structure. DFT calculations revealed the existence of an isoenergetic higher triplet state (T-8) and comparatively weak spin-orbit coupling (T-1-S-0), thereby enabling the bent nanographene to exhibit a long-lived component and strong afterglow. Our findings highlight the significance of regioisomeric nanographenes with exceptional optical properties and offer a deeper understanding of the structure-property relationship in nonplanar nanographenes.</p>
10aAfterglow10aCPL10aHelicenes10ananographene10aPhosphorescence10aTADF1 aKumar, Viksit1 aVenugopal, Geethu1 aJadhav, Ashok, Badrinaray1 aDongre, Sangram, D.1 aGonnade, Rajesh1 aKumar, Jatish1 aRuer, Paul, C.1 aHupp, Benjamin1 aSteffen, Andreas1 aBabu, Sukumaran, Santhosh  uhttps://library.ncl.res.in/content/regioisomeric-%CF%80-extended-nanographene-long-lived-phosphorescence-afterglow