Diamondoid Nanostructures as sp 3 ‐Carbon‐Based Gas Sensors

Diamondoids, sp 3 ‐hybridized nanometer‐sized diamond‐like hydrocarbons (nanodiamonds), difunctionalized with hydroxy and primary phosphine oxide groups, enable the assembly of the first sp 3 ‐C‐based chemical sensors by vapor deposition. Both pristine nanodiamonds and palladium nanolayered composites can be used to detect toxic NO 2 and NH 3 gases. This carbon‐based gas sensor technology allows reversible NO 2 detection down to 50 ppb and NH 3 detection at 25–100 ppm concentration with fast response and recovery processes at 100 °C. Reversible gas adsorption and detection is compatible with 50 % humidity conditions. Semiconducting p‐type sensing properties are achieved from devices based on primary phosphine–diamantanol, in which high specific area (ca. 140 m 2 g −1 ) and channel nanoporosity derive from H‐bonding.