@article {49679,
	title = {Steric hindrance modulated efficient thermally activated delayed fluorescence with non-linear optical, ferroelectric and piezoelectric properties},
	journal = {Chemical Science},
	volume = {16},
	year = {2025},
	month = {JUL},
	pages = {11989-11998},
	type = {Article},
	abstract = {<p>
	Multi-carbazole-based benzonitrile systems are efficient thermally activated delayed fluorescence (TADF) materials for organic light-emitting diodes (OLEDs). However, they suffer from low PLQY due to the large dihedral angle arising from steric crowding. Addressing this challenge, we demonstrate a potent strategy to engineer steric crowding in this work. To achieve our goal, we have designed three luminogens, namely, CzPHCN, tCzPHCN and Cz2CzPHCN based on phenanthrene-9,10-dicarbonitrile (PHCN), as an acceptor core to minimize the steric hindrance between the donor groups. Among the three luminogens, tCzPHCN exhibits a maximum PLQY of 86\% and the highest RISC rate of 3.5 x 105 s-1, the underlying cause being the least dihedral angle of 45.72 degrees and suppressed intermolecular interaction due to the presence of the bulky tert-butyl group. Interestingly, our QM/MM calculations and experimental evidence suggest that the RISC process of both CzPHCN and tCzPHCN takes place via a hot exciton channel. Unlocking a new realm of applications, the unique non-centrosymmetric space group (Cmc21) of CzPHCN offers excellent SHG with a chi(2) value of 0.21 pm V-1 at 1320 nm. In addition to this, the molecule depicts good ferroelectric (PS = 0.32 mu C cm-2), piezoelectric energy harvesting (VOC = 2.8 V) and two-photon absorption properties.</p>
},
	issn = {2041-6520},
	doi = {10.1039/d5sc02107c},
	author = {Dutta, Madhusudan and Chatterjee, Abhijit and Deka, Nilotpal and Tanwar, Riteeka and Mishra, Vishnu and Saha, Arindam and Mandal, Pankaj and Boomishankar, Ramamoorthy and Hazra, Partha}
}
@article {50129,
	title = {Harnessing strong chiroptical nonlinearity in carbene-copper-amides through center-specific chirality: an approach to amplified dissymmetry},
	journal = {Journal of the American Chemical Society},
	volume = {148},
	year = {2026},
	month = {JUN},
	pages = {23238-23253},
	type = {Article},
	abstract = {<p>
	We present the design, synthesis, and photophysical characterization of a new class of chiral N-heterocyclic carbene (NHC)-copper(I)-amide (CMA) complexes with enantiomerically pure phenylethylamine motifs within the amide framework. These chiral CMA complexes represent a new class of mononuclear molecular Cu(I) complexes exhibiting pronounced chiral nonlinear optical (NLO) activity, which are actively being researched for advanced optoelectronic applications such as advanced photonics, biosensing, and security. The intrinsic molecular chirality and noncentrosymmetric crystal packing collectively enable strong second-harmonic generation (SHG) responses in the presence of circularly polarized (CP) light. Notably, these complexes display impressive SHG circular dichroism factors (g SHG-CD) as high as +/- 0.40 at 1000 nm, equaling or surpassing state-of-the-art chiral perovskites in this domain. Beyond their exceptional NLO response, the complexes exhibit dual emissive behavior, originating from both singlet and triplet excited states, with absolute quantum yields reaching 30\%, and validated by TD-DFT calculations. The air-sensitive phosphorescence (similar to 550 nm) efficiently generates singlet oxygen (1O2), confirmed by PPh3 photooxidation and TEMPO radical generation. Remarkably, the emission can be reversibly switched between pure singlet and mixed singlet-triplet states by external modulation of O2, maintaining photostability over multiple oxic-anoxic cycles up to 5 days. These findings establish chiral CMA complexes as a new class of NHC-ligated molecular Cu(I) systems to display circularly polarized NLO activity with reversible photoluminescent switching, opening new avenues for exploring main-group organometallic compounds in next-generation polarization-sensitive photonic devices.</p>
},
	issn = {0002-7863},
	doi = {10.1021/jacs.6c06543},
	author = {Ghosh, Moushakhi and Tanwar, Riteeka and Panwaria, Prakash and Chatterjee, Abhijit and Panday, Rishukumar and Akhtar, Ruksana and Venugopal, Geethu and Mandal, Pankaj and Khan, Shabana}
}
