Ultrasensitive, ultrathin vapor sensors and arrays

Inventors

Gregory, Otto J. • RICCI, Peter P.

Assignees

TRACE SENSING TECHNOLOGIES INC.

Abstract

Ultrasensitive, ultrathin thermodynamic sensing platforms for the detection of chemical compounds in the vapor phase at trace levels are disclosed. Embodiments of the ultrathin vapor sensor comprise a substrate layer, an adhesion layer, a metallic microheater layer, and a catalyst layer. A sensor array may be provided including a plurality of sensors each having a different catalyst. When a sensor array exposed to an analyte, each of the various ultrathin vapor sensors of the array may experience an endothermic reaction, an exothermic reaction, or no reaction. A comparison of the reaction results to data comprising previously-obtained reaction results may be used to determine the presence and the identity of the analyte. Advantageously, these ultrathin vapor sensors utilize less power and provide greater sensitivity than known systems, and may be used to detect and identify analytes at the parts per trillion level. Specialized sensors configured to detect analytes falling into a certain category (e.g., explosives, drugs and narcotics, biomarkers, etc.) as disclosed, as well as general purpose sensors capable of detecting analytes from a plurality of categories.

Core Innovation

The invention provides a detection device for vapor-phase analyte detection that includes a layered structure with a substrate, an adhesion layer, a metallic microheater, and a catalyst layer. Power is applied to the metallic microheater at a first power level to reach a setpoint temperature, and after the catalyst begins a chemical reaction when exposed to an analyte, power is applied at a second power level to maintain the setpoint temperature. The catalyst layer is configured such that the chemical reaction is endothermic or exothermic when exposed to the analyte.

A heat effect indicative of information on the analyte is determined by comparing the second power level to the first power level. In this way, the detector converts the analyte-driven thermal response into an analyte-related comparison between power levels used to maintain the setpoint temperature. The layered device can include a reference microheater sensor without a catalyst to mitigate misidentification by enabling comparison against a catalyst-free baseline.

The invention further provides a sensor array that includes first and second sensors, each having a microheater layer and a catalyst layer in contact with the microheater layer. Both sensors are heated to respective setpoint temperatures by delivering power, then exposed to an analyte such that one or both catalyst layers react with the analyte to generate a thermal response. Power applied to the sensors is varied to maintain the first and second setpoint temperatures, and an existence, identity, and/or concentration of the analyte is determined based on the varied power.

In the sensor array approach, analyte determination can be performed by comparing the thermal responses to a database of known thermal responses and optionally by using a reference sensor to base determination on power supplied to the reference sensor. Example catalyst materials include metal oxides such as SnO, ITO, WO, MnO, Al2CuO4, AZO, CrO2, CuO, CoO2, Fe2O3, IrO2, and RuO2. The approach is described as enabling ultrasensitive detection of vapor-phase analytes at trace-level concentrations down to parts per trillion (ppt), with stated motivations including reduced thermal mass and improved sensitivity/selectivity compared with thicker systems.

Claims Coverage

The independent claims explicitly define three main inventive structures: (i) a single layered detection device using first and second power levels to maintain a setpoint and determine a heat effect; (ii) a two-sensor controller-based device varying power for two setpoint temperatures to determine analyte existence/identity/concentration; and (iii) a method using a sensor array with first and second sensors, varying power to maintain setpoints, and determining existence/identity/concentration based on varying power.

Across the independent claims, the core inventive coverage is the use of catalyst-reacted thermal responses monitored through power variation required to maintain one or more setpoint temperatures, with the resulting heat effect or varied power used to determine analyte existence, identity, and/or concentration.

Stated Advantages

Documented Applications