Tailor-made photonic crystal fiber sensor for the selective detection of formaldehyde and benzene

Abstract

Abstract Designability and adaptability are of paramount importance in the production and use of photonic crystal fiber (PCF) sensors. It is still challenging to distinguish different gases in fabricating opto-devices and gas sensors for the detection of toxic gases at low concentrations. Here, we explore a tailor-made PCF sensor based on Bragg diffraction. The silicon fiber array acts as the optical fiber cladding, and the air hole serves as the core. The coating materials are carbon nanotubes (CNT) and CdO-CNT composites, which can respectively serve as the selective “turn-on” detectors for perceiving the benzene and formaldehyde by the preferential adsorption. The CNT has a more pronounced response to benzene (0.8 nm/10 ppm) than other gases, while CdO-CNT has strong selectivity to formaldehyde (1.2 nm/10 ppm). The two sensors show strong selectivity, linear sensitivity, and good response recovery capability. The CNT and CdO-CNT coating PCF sensors can play the part of a sensor array to identify benzene and formaldehyde, which have the advantages of easily assembly and excellent selectivity, showing potential for the detection of harmful gases at low concentrations.