Real-time, noise and drift resilient formaldehyde sensing at room temperature with aerogel filaments

Abstract

Formaldehyde, a known human carcinogen, is a common indoor air pollutant. However, its real-time and selective recognition from interfering gases remains challenging, especially for low-power sensors suffering from noise and baseline drift. We report a fully 3D-printed quantum dot/graphene-based aerogel sensor for highly sensitive and real-time recognition of formaldehyde at room temperature. By optimizing the morphology and doping of printed structures, we achieve a record-high and stable response of 15.23% for 1 part per million formaldehyde and an ultralow detection limit of 8.02 parts per billion consuming only ∼130-microwatt power. On the basis of measured dynamic response snapshots, we also develop intelligent computational algorithms for robust and accurate detection in real time despite simulated substantial noise and baseline drift, hitherto unachievable for room temperature sensors. Our framework in combining materials engineering, structural design, and computational algorithm to capture dynamic response offers unprecedented real-time identification capabilities of formaldehyde and other volatile organic compounds at room temperature.

Universal Murray’s law for optimised fluid transport in synthetic structures

“…The gas sensor is prepared by SnO 2 quantum dots (QDs) decorated GOA as shown in Fig. 4 a 44 . SnO 2 QD-decorated GO ink is synthesised through a surfactant-assisted hydrothermal growth process (see Methods for details).…”

“…Transmission electron microscopy (TEM) images of as-prepared GO ink (Fig. 4 b–d) demonstrate uniformly distributed SnO 2 QDs on GO sheets, with size smaller than twice the exciton Bohr radius (2.7 nm) of SnO 2 44 . The lattice fringes of 2.5 and 3.3 Å in Fig.…”

“…SnO 2 QD-decorated GOA for room-temperature gas sensing is synthesised following our previous publication 44 . In a typical process, SnO 2 precursor is first synthesised by dissolving 4 mM of tin chloride pentahydrate (SnCl 4 ⋅ 5H 2 O, Sigma-Aldrich) and 4 mM of 6-aminohexanoic acid (AHA, Sigma-Aldrich) in 30 mL DI water, followed by 5 min of sonication.…”