Abstract
We discuss a recently proposed novel photonic approach for enhancing the fluorescence of extremely thin chemosensing polymer layers. We present theoretical and experimental results demonstrating the concept of gain-assisted waveguided energy transfer (G-WET) on a very thin polymer nanolayer spincoated on an active ZnO thin film. The G-WET approach is shown to result in an 8-fold increase in polymer fluorescence. We then extend the G-WET concept to nanostructured media. The benefits of using active nanostructured substrates on the sensitivity and fluorescence of chemosensing polymers are discussed. Preliminary theoretical results on enlarged sensing surface and photonic band-gap are presented.
Highlights
With the rising illicit use of improvised explosive devices, explosives trace detection has become a major societal, governmental and military concern
ZnO is largely investigated as a low-cost effective replacement for ultraviolet (UV) emitting materials, such as gallium nitride (GaN), due to its direct-wide-gap (~3.3 eV) and large exciton binding energy (~60 meV), typically 2.4 times higher than room-temperature thermal energy (~25 meV), which allows for intense excitonic near-band-edge emission and laser action at room temperature
The theoretical modeling, presented considers the case of an extremely thin (5 nm) fluorescence sensing polymers (FSPs) layer coated on a ZnO thin film grown on a sapphire substrate
Summary
With the rising illicit use of improvised explosive devices, explosives trace detection has become a major societal, governmental and military concern. For 20 nm thick polymer film, the group observed only a 30% fluorescence quenching at 60 s of exposure to TNT. Under similar experimental conditions as [9], the triphenylene-based PPE thin films showed a 4-fold increase in sensitivity towards TNT vapor (75% fluorescence quenching within 10 s). The polymer presented no fluorescence quenching when exposed to other oxidizing reagent vapors Due to their interesting sensing properties, fluorescence sensing polymers (FSPs) have, far, emerged as the most promising chemosensing materials for explosives trace detection applications. Most of the FSP-based chemosensing results were reported on extremely thin polymer layers, which do not exceed a thickness of 10 nm. The increase of the fluorescence signal of extremely thin FSP layers is a major challenge for achieving the required LOD for explosives trace detection. An extension of the G-WET concept towards more complex photonic structure is discussed later on
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
