Single- and dual-band quantum dot-based nanoporous solid-state lasers for gas sensing

Abstract

A laser-based nitrogen dioxide (NO₂) gas sensing system was engineered by combining nanoporous anodic alumina random laser (NAA–RL) platforms and quantum dots (QDs). Core–shell CdSe/ZnS QDs were embedded within optimized NAA–RL structures with controlled pore diameter and length, enabling highly efficient lasing systems characterized by narrow emission bandwidths, high intensity, and low lasing thresholds. Unlike conventional spectroscopic detection techniques that operate external to the laser medium, NO₂ sensing is achieved via in situ quenching of lasing emissions induced by the selective interaction of gas with the QD–NAA–RL matrix. Single-QD platforms demonstrated strong gas sensing performance, with the most sensitive platform achieving a sensitivity of 220.48 a.u. ppmv⁻¹ and a limit of detection of 0.367 ppmv. The dual-QD system incorporating two types of QDs into a single NAA–PL platform provided enhanced selectivity and a broader spectral response for NO₂ detection, achieving a sensitivity of 238.47 a.u. ppmv⁻¹ and a limit of detection of 0.340 ppmv. Selectivity tests with ETOH vapor confirmed the specificity of the QD–NAA–RL platforms to NO₂ gas. The system also exhibited reversible lasing quenching behavior, demonstrating its suitability for real-time detection of harmful gases. These findings highlight the potential of QD–NAA–RL platforms as highly sensitive and selective tools for gas sensing, offering a promising solution for environmental monitoring and industrial safety applications.