Hypothesizing the applicability of the principle of linear combination in predicting sensing behaviors of quantum dots: A deeper understanding of the precise tuning of quantum dot properties with capping composition

Abstract

In this paper we intend to demonstrate, for the first time, the relevance of the hypothesis based on the linear combination principle (LCP) in devising materials that may exhibit intermediate of their pure-state-like behaviors. To the best of our knowledge, the present study embodies the first attempt in demonstrating why the hypothesis can be pertinent for nano-sized materials. In doing so, we have picked up the CdS QDs as model system and two structurally similar thiols as capping agents (3-mercaptopropionic acid, MPA, and thiolactic acid, TLA). Here, we attempted fabrication of mixed dual thiol capped CdS QDs (abbreviated as mDTCQ) employing mixture of two thiols to assess the effects of composition of capping mixture on the sensochemical characteristics of QDs. We showcased that the selectivity and also sensitivity of mDTCQ toward two metals (Ni and Pb) via photoluminescence (PL) turn-off based strategy can be tuned as per linear combination principle which is found to hold good as a function of mole percentages of capping agents used during synthesis. Importantly, in the present context; we would like to draw the attention of the readers that the results are the stepping stones toward understanding the origin of senso-selection of nanomaterials and is not just something that can be misinterpreted as incremental to the existing reports.