Selectively activated suppressed quantum networks in self-assembled single-atom Ag catalyst-based room-temperature sensors for health monitoring

Abstract

The critical element in the development of multifunctional hybrid materials is efficiently harnessing the multi-mode suppressed quantum pathways produced by a planned material architecture. However, the complex layout of these in-built networks usually leads to unrecognizable intersecting pathways with uncontrolled electron movement, compromising the efficiency of the system. Thus, the development of a material system where these networks are not only distinct and non-intersecting but also controllable using external stimuli is a challenge. In this work, a novel 2-step synthesis technique is introduced to develop a hybrid material with a dual-mode in-built quantum network for multidimensional applications. Single-atom Ag catalysts were self-assembled on a terminally modified n-octanol monolayer developed via self-assembly on a flexible CdS quantum dot (QD) substrate. The novel Ag@n-octanol(ox)@CdS-QD systems were identified as ultrasensitive room-temperature sensors capable of detecting ethanol at the ppb level in in situ and ex situ modes. The ex situ sensing capability of the material was harnessed to detect pulmonary disorders by analyzing exhaled human breath. The material architecture facilitates two electrically isolated orthogonal pathways for sensing processes to proceed: one through the formation of interfacial bound states (identified at low temperatures via in situ photoluminescence spectroscopy) and the other through a polarity-induced p-dielectric-n heterostructure, selectively activated by the duration of surface catalytic interactions with the target analyte.