Ultratrace Nitroaromatic Vapor Detection via Surface-Enhanced Fluorescence on Carbazole-Terminated Black Silicon

Abstract

Detection of nitroaromatic compounds (NACs) is an important applied task for environmental monitoring, medical diagnostics, and forensic analysis. However, detection of NAC vapors is challenging owing to their low vapor pressure and relatively weak sensitivity of the existing detection techniques. Here, we propose a novel concept to design fluorescence (FL) detection platforms based on chemical functionalization of nanotextured dielectric surfaces exhibiting resonant light absorption, trapping, and localization effects. We demonstrate highly-efficient NAC vapor sensor with selective FL-quenching response from monolayers of carbazole moieties covalently bonded to a spiky silicon surface, “black” silicon, produced over the centimeter-scale area using simple reactive ion etching. The sensor is shown to provide unprecedented ppt (10–12) range limits of detection for several NAC vapors. Easy-to-implement scalable fabrication procedure combined with simple and versatile functionalization techniques applicable to all-dielectric surfaces make the suggested concept promising for realization of various gas sensing systems for social and environmental safety applications.

Recent Progress of Black Silicon: From Fabrications to Applications

“…In 2019, A. Mironenko [111] fabricated a black silicon-based ultra-sensitive d by attaching a carbazole monolayer on the surface of nanostructured black silicon achieve a sensitivity test as low as 10 −12 and a dynamic test range as high as 10 PPM 13d shows the comparison of FL quenching efficiency in different targets. Due to t ence of the carbazole monolayer, the luminescence spectrum of the reaction betw carbazole monolayer and the aromatic nitro molecule can be used to identify the p of the aromatic nitro molecule.…”

“…(d) Evaluate detection limits of cbz-bSi gas sensor. Adapted from reference [111], with permission from American Chemical Society © 2020.…”

“…In 2019, A. Mironenko [111] fabricated a black silicon-based ultra-sensitive detector by attaching a carbazole monolayer on the surface of nanostructured black silicon. It can achieve a sensitivity test as low as 10 −12 and a dynamic test range as high as 10 PPM.…”

Direct Femtosecond Laser Fabrication of Chemically Functionalized Ultra-Black Textures on Silicon for Sensing Applications

“…The thickness of attached layers is usually on the order of several nanometers, which requires sufficiently sensitive equipment when optical chemosensors are used. In this work, a thin fluorescent layer was attached to a nano-textured substrate, which, as was shown earlier [34,37], provides a significant enhancement of PL emission that can be easily detected by standard equipment. Noteworthily, dielectric structures are advantageous for the realization of the sensors based on PL enhancement effects.…”

Carrier excitation dynamics in black silicon nano pillar arrays

“…realization of the photothermic conversion devices 21 . Isolating particles of interest within the forest of quantum nanosized pillars or using surface functionalizing techniques enables us to enhance the sensitivity while providing an advantage of filtering the particles to be detected 8,20 . Black silicon may find applications in imaging and micro-electro-mechanical systems (MEMS) as active and passive micro and nanostructured semiconductor quantum structures 22,23 .…”