Multi-sensing Platform Based on Two-Dimensional Monoelement Germanane.

Abstract

Covalently functionalized germanane is a novel type of fluorescent probe that can be employed in material science and analytical sensing. Here, we developed a fluorometric sensing platform based on methyl-functionalized germanane (CH3 Ge) for gas (humidity and ammonia) sensing, pH (1-9) sensing, and anti-counterfeiting. A luminescence (red-orange) is seen when a gas molecule intercalates into the interlayer space of CH3 Ge and the luminescence disappears upon deintercalation. This allows for direct detection of gas absorption via fluorometric measurements of the CH3 Ge. Structural and optical properties of CH3 Ge with intercalated gas molecules are investigated by density functional theory. To demonstrate real-time and on-the-spot testing, we first precisely quantified absorbed gas molecules (humidity and ammonia) by CH3 Ge using a smartphone camera with an installed color intensity processing application (APP). Further, CH3 Ge film was integrated into real food packets (e.g., fish and milk) to monitor the shelf life of perishable foods. The band gap changes and optical response of CH3 Ge to various gas molecules were examined using density functional theory calculations. Finally, CH3Ge-based rewritable paper was applied in water jet printing to illustrate the potential for secret communication with quick coloration and good reversibility by water evaporation. This article is protected by copyright. All rights reserved.