Fluorescence ON-OFF switching, Boolean logic gates like behavior of carbon quantum dots and highly sensitive bovine serum albumin sensing

Abstract

We demonstrate fluorescence “ON-OFF” switching and photonic logic gates based on fluorescence response of carbon quantum dots (CQDs) in the presence of graphene oxide (GO), reduced graphene oxide (RGO), and bovine serum albumin (BSA). We study the excited state electron and energy transfer interactions among the carbon based materials in detail through steady state fluorescence (SSF) and time resolved fluorescence (TRF) spectroscopy. CQDs function as donor; GO and RGO function as acceptors. SSF results show the fluorescence “turn-OFF” behavior of CQDs in the presence of GO and RGO, and the reason is explained through Stern-Volmer plots. TRF results reveal a decrease in the decay time components of CQDs in the presence of GO and RGO. The gradual recovery of quenched fluorescence of CQDs is observed by the addition of BSA at nanomolar concentrations which shows the highly sensitive “turn-ON” BSA sensing. Single input and two inputs photonic logic gates are implemented based on the fluorescence response of CQDs in the presence of GO, RGO, and BSA in different input combinations. The not, pass1, nor, and implication gates like behavior of CQDs is demonstrated.