Understanding the Interaction between Inorganic and Organic Excitonic Components of an Inorganic-Organic Nanohybrid Associate

The present study deals with the design, formation, and photophysical studies on light-harvesting inorganic-organic nanohybrid associates comprising a less-toxic, inorganic core-shell QD (Cu-In-S/ZnS) and an organic S0041 dye aggregate. One of the main objectives of this study is to understand the interaction between the inorganic and organic excitonic components of the hybrid system and its implication on the photophysical response of the system. The nanohybrid associate have been obtained through the self-assembly of S0041 dye molecules (organic exciton) onto Cu-In-S/ZnS QD (inorganic exciton). The characterization of as-synthesized QD have been done by conventional microscopic and spectroscopic measurements. The exciton domain length for the organic dye aggregates is estimated to be 24 nm. Steady-state absorption, emission, and time-resolved photoluminescence (PL) intensity decay measurements have been carried out to understand the interaction mechanism between inorganic and organic excitonic components and the overall photophysical behaviour of the hybrid system. The studies have revealed that the formation of hybrid associate is electrostatically driven and thermodynamically feasible. Interestingly, steady-state and time-resolved PL decay measurements and their analysis have revealed that the interaction between inorganic QD and organic aggregate is mediated through dipole-dipole Forster energy transfer (ET) mechanism and the ET efficiency is found to be as high as 95%. The present system is expected to be used in fabrication of less-toxic nanoscale light-harvesting system.