Bucket Effect to Improve Third‐Order Nonlinear Optical Response on Metal‐Heteroaromatic Compounds

Comprehensive Summary Carbolong compounds as a metal-heteroaromatic compound with both organometallic properties and pi-conjugated systems exhibit great potential in organic catalysis and optoelectronic devices. In this work, for the first time, the "Bucket Effect" is revealed to promote the third-order nonlinear optical (NLO) performance in metal-heteroaromatic compounds. We have successfully constructed and investigated a series of novel metallapentalenes with higher third-order NLO performance benefited from the "Bucket Effect". Meanwhile, aromaticity and electron-hole analysis further confirm the internal homogeneity of organometallic rings, reduced bandgap, and enhanced low-energy peak response resulted in the enhanced third-order NLO effects. The success of this work is discovering an emerging material library of high third-order NLO effects, and illustrating the feasibility of engineering the high response metal-heteroaromatic optical devices at the electronic structure level.