Metallic Ti₃C₂T_x MXene Gas Sensors with Ultrahigh Signal-to-Noise Ratio

Abstract

Achieving high sensitivity in solid-state gas sensors can allow the precise detection of chemical agents. In particular, detection of volatile organic compounds (VOCs) at the parts per billion (ppb) level is critical for the early diagnosis of diseases. To obtain high sensitivity, two requirements need to be simultaneously satisfied: (i) low electrical noise and (ii) strong signal, which existing sensor materials cannot meet. Here, we demonstrate that 2D metal carbide MXenes, which possess high metallic conductivity for low noise and a fully functionalized surface for a strong signal, greatly outperform the sensitivity of conventional semiconductor channel materials. TiCT MXene gas sensors exhibited a very low limit of detection of 50-100 ppb for VOC gases at room temperature. Also, the extremely low noise led to a signal-to-noise ratio 2 orders of magnitude higher than that of other 2D materials, surpassing the best sensors known. Our results provide insight in utilizing highly functionalized metallic sensing channels for developing highly sensitive sensors.

A New Memristor with 2D Ti3C2Tx MXene Flakes as an Artificial Bio‐Synapse

“…The C 1s core‐level energy spectrum (Figure g) is fitted with five components at 282.3, 284.6, 285.6, and 289.1 eV, attributed to CTi, CC, CC/CH, and CF, respectively. For the O 1s core‐level energy spectrum (Figure h), three components at 530.1, 530.6, and 532.5 eV, which were attributable to sub‐stoichiometric TiO 2 , TiOTi, and TiOH, respectively, are fitted …”

White Photoluminescent Ti3C2 MXene Quantum Dots with Two‐Photon Fluorescence

“…The outstanding properties of MXenes distinguish them from traditional 2D materials and make them promising candidates for energy storage and environmental applications, such as supercapacitors, lithium-ion batteries, and pollution treatment. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] The recent decomposition of 2D nanosheets into 0D nanodots has been used to develop materials for photocatalysis, sensors, and energy conversion owing to the unique confinement effect of 0D structures. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] The recent decomposition of 2D nanosheets into 0D nanodots has been used to develop materials for photocatalysis, sensors, and energy conversion owing to the unique confinement effect of 0D structures.…”

High‐Performance Electrocatalytic Conversion of N2 to NH3 Using Oxygen‐Vacancy‐Rich TiO2 In Situ Grown on Ti3C2Tx MXene

“…[30][31][32] The MXenes have already showed their significant applicability in biosensors, [33] electromagnetic wave absorption, [34] supercapacitors, [35,36] Li-ion batteries, [37,38] electronic devices, [39,40] gas sensors, [41] etc., because of their high conductivity, [42] hydrophilic surface, [43] and flexibility. Their general formula is recorded as M n+1 X n T x , where "M" stands for the transition metal element, "X" is C or N or CN, while T x represents the terminal groups of -OH or -F, etc., and n could be 1, 2, or 3.…”