Monolayer Two‐dimensional Molecular Crystals for an Ultrasensitive OFET‐based Chemical Sensor

Abstract

The sensitivity of conventional thin‐film OFET‐based sensors is limited by the diffusion of analytes through bulk films and remains the central challenge in sensing technology. Now, for the first time, an ultrasensitive (sub‐ppb level) sensor is reported that exploits n‐type monolayer molecular crystals (MMCs) with porous two‐dimensional structures. Thanks to monolayer crystal structure of NDI3HU‐DTYM2 (NDI) and controlled formation of porous structure, a world‐record detection limit of NH3 (0.1 ppb) was achieved. Moreover, the MMC‐OFETs also enabled direct detection of solid analytes of biological amine derivatives, such as dopamine at an extremely low concentration of 500 ppb. The remarkably improved sensing performances of MMC‐OFETs opens up the possibility of engineering OFETs for ultrasensitive (bio)chemical sensing.

Graphene‐Quantum‐Dots‐Induced Centimeter‐Sized Growth of Monolayer Organic Crystals for High‐Performance Transistors

“…Moreover, the mobility of the monolayer C 10 ‐BTBT crystal is significantly higher than that of the monolayer crystals obtained by the LB method (<0.01 cm 2 V −1 s −1 ) and solution‐epitaxial self‐assembly method (<0.022 cm 2 V −1 s −1 ) on water surface, [ 13–16,22,41–44 ] and is also higher than that of the self‐assembled monolayer organic crystals on the rigid substrate (0.1–1 cm 2 V −1 s −1 ). [ 5,6,32,45–54 ] This result unambiguously demonstrates the enormous potential of the GQDs‐induced self‐assembly method for the large‐scale growth of high‐quality monolayer organic crystals. Also, various potential improvements for the device performance of monolayer organic crystal‐based OFETs can be envisioned including replacing the thermally evaporated electrodes with transferred electrodes, [ 24 ] modifying the crystal/dielectric interface, [ 55 ] and further optimizing the growth conditions.…”

Recent Advances in Flexible Field‐Effect Transistors toward Wearable Sensors

“…[83][84][85][86] Researchers have proposed various kinds of sensors to detect the mechanical deformation of humans and products, [55,57,[87][88][89][90][91] aiming to integrate sensing information with applications in intelligent portable devices and biomedical engineering. [92][93][94] In this section, we introduce the state-of-the-art research on F-FET sensors that are used for detecting pressure and strains and future human-machine interactions. Sensors detect the external pressure changes primarily based on three mechanisms: piezoelectricity changes, [95][96][97] capacitance changes, [98,99] and piezoresistivity changes, [100,101] as shown in Figure 3.…”

“…[32,244] 1D and 2D materials were also widely used in increasing the sensitivity of (bio)chemical sensors, [245,246] such as introducing nanowires and nanotubes into the active layers to form the direct path for charge transport. [247][248][249] Pentacene/TSB3 [71] 6.3 Methanol vapor NA NA NA Nanoporous-structured semiconductor NDI3HU-DTYM2 [92] NA NH 3 NA 0.1 ppb NA Porous monolayer P3HT-azide [32] 0.32 Liquid analytes NA 1% methanol or ethanol NA (PEN) Container molecules Pentacene [34] 0.014 DNA 74 ng cm À2 650 ng ml À1 NA NA Graphene [205] NA DNA NA %1 fM NA ssDNA on Au electrodes Graphene:PDMS [204] NA DNA NA %1 nM NA Solution gated…”

Structured and functionalized organic semiconductors for chemical and biological sensors based on organic field effect transistors

“…2), an n-type organic semiconductor, by tuning the concentration of NDI3HU-DTYM2 and varying the substrates in the drop-casting process. 40 These porous monolayer crystals enabled OFET-based sensors for NH 3 in gas with a record low detection limit of 0.1 ppb and relative sensitivity of 720% ppb À1 owing to the unique combination of nanopores and the monolayer structure. In contrast, the non-porous monolayer OFETs exhibited a relative sensitivity of 73% ppb À1 in response to 1 ppb NH 3 , and the multilayer OFETs only exhibited a relative sensitivity of 0.18% ppm À1 in response to 10 ppm NH 3 .…”