Toward Efficient Toxic-Gas Detectors: Exploring Molecular Interactions of Sarin and Dimethyl Methylphosphonate with Metal-Centered Phthalocyanine Structures.

Hazem Aldahhak,Uwe Gerstmann,Fernando B Dias,Wolf Gero Schmidt,Maciej Krzywiecki,Paulina Powroźnik,Wiesław Jakubik,Piotr Pander

doi:10.1021/acs.jpcc.9b11116

Abstract

The rapid and reliable detection of lethal agents such as sarin is of increasing importance. Here, density-functional theory (DFT) is used to compare the interaction of sarin with single-metal-centered phthalocyanine (MPc) and MPc layer structures to a benign model system, i.e., the adsorption of dimethyl methylphosphonate (DMMP). The calculations show that sarin and DMMP behave nearly identical to the various MPcs studied. Among NiPc, CuPc, CoPc, and zinc phthalocyanine (ZnPc), we find the interaction of both sarin and DMMP to be the strongest with ZnPc, both in terms of interaction energy and adsorption-induced work function changes. ZnPc is thus proposed as a promising sensor for sarin detection. Using X-ray photoelectron spectroscopy, the theoretically predicted charge transfer from DMMP to ZnPc is confirmed and identified as a key component in the sensing mechanism.

Highlights

Gas sensors have been attracting increasing interest due to their wide range of applications spanning across environmental protection, detection of combustion gases, medical diagnosis, and military and civil safety.[1−4] The relevance of these applications has led to intense research in the area of detection techniques and sensing materials
Thereby, we explore the adsorption of both dimethyl methylphosphonate (DMMP) and sarin on a variety of single metal-centered phthalocyanine (MPc) (NiPc, CuPc, CoPc, and zinc phthalocyanine (ZnPc)) molecules
We use ZnPc as a primary example for MPc: it turns out to provide the strongest interaction with DMMP and sarin

Summary

Introduction

Gas sensors have been attracting increasing interest due to their wide range of applications spanning across environmental protection, detection of combustion gases, medical diagnosis, and military and civil safety.[1−4] The relevance of these applications has led to intense research in the area of detection techniques and sensing materials. The thorough, atom-scale understanding of the sensing mechanism is expected to be extremely helpful to tune respective devices and eventually to realize competitive sensor components for industrial production. The gas adsorption and its impact on the sensing material are of crucial importance for the sensor design.[12−16]

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