Ultrafast carrier dynamics in 2D-2D hybrid structures of functionalized GO and CdSe nanoplatelets

Considerable attention has been paid to designing graphene based 2D hybrid nanostructures for their potential applications in various areas from healthcare to energy harvesting. Herein, we have prepared 2D-2D hybrid structures of 2D CdSe nanoplatelets (NPLs) with thiol (-SH) functionalized reduced graphene oxide (G-Ph-SH). Microscopic and spectroscopic studies reveal that the G-Ph-SH surface is successfully decorated by CdSe NPLs through a thiophenol (-SH) linker. The significant photoluminescence quenching (65%) and the shortening of decay time from 1 ns to 0.4 ns of CdSe NPLs are observed after adding 100 μg of G-Ph-SH. Furthermore, the femto-second transient absorption spectroscopic (fs-TAS) study reveals that the growth time of CdSe NPLs in the composite is reduced to 0.4 ps from 0.8 ps due to faster hot electron cooling. A faster component of 1.4 ps in the kinetic parameters of the composite system further suggests that the ultrafast electron transfer occurs from the conduction band of CdSe NPLs to surface functionalized reduced graphene oxide. This type of 2D-2D hybrid structure may open up new possibilities in light harvesting applications.