High performance Pt(II) complex and its hybridized carbon quantum dots: Synthesis and the synergistic enhanced optical limiting property

A new strategy is launched to develop efficient nonlinear optical (NLO) materials by incorporating organometallic Pt(II) complexes into carbon quantum dots (CQDs), which exhibits the synergistic effect for the optical limiting performance of hybrid materials. m1-CDs were further functionalized with Pt(II) complex for the smaller sizes (2.3 nm) and more surface amino groups (54.6 %), and the Pt(II) complex also shows long triplet-excited lifetime (482 ns) and satisfactory reverse saturable absorption (RSA). The hybrid material N-CD-Pt exhibits the special π − π* transitions and broader metal-to-ligand/intraligand/ligand-to-ligand charge transfer transitions in the visible region (∼675 nm). The electron/energy transfer process occurred among the system causes a significant emission quenching for the nanohybrid, which is benefit for the occurrence of excited-state absorption process and the enhancement of the RSA. The covalent modification also endows nanohybrid N-CD-Pt with improved NLO performance, including RSA behaviors mainly from the Pt(II) complexes and nonlinear scattering responses from CQDs. The limiting threshold (F₅₀) of N-CD-Pt reaches 0.62 J·cm⁻² at 532 nm, which is better than Pt(II) complex (1.0 J·cm⁻²).