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This review provides an update on advances in the area of electrical mode sensors using organic small molecule n-type semiconductors based on perylene. Among small organic molecules, perylene diimides (PDIs) are an important class of materials due to their outstanding thermal, chemical, electronic, and optical properties, all of which make them promising candidates for a wide range of organic electronic devices including sensors, organic solar cells, organic field-effect transistors, and organic light-emitting diodes. This is mainly due to their electron-withdrawing nature and significant charge transfer properties. Perylene-based sensors of this type show high sensing performance towards various analytes, particularly reducing gases like ammonia and hydrazine, but there are several issues that need to be addressed including the selectivity towards a specific gas, the effect of relative humidity, and operating temperature. In this review, we focus on the strategies and design principles applied to the gas-sensing performance of PDI-based devices, including resistive sensors, amperometric sensors, and operating at room temperature. The device properties and sensing mechanisms for different analytes, focusing on hydrazine and ammonia, are studied in detail, and some future research perspectives are discussed for this promising field. We hope the discussed results and examples inspire new forms of molecular engineering and begin to open opportunities for other rylene diimide classes to be applied as active materials.

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In this work, polyvinyl alcohol (PVA) is chemically bonded to carbon nanoparticles (CNPs) by a very simple and versatile solution casting method. Five different kinds of CNPs/PVA composite films were prepared; 0.5, 1.0, 1.5, 2.0, and 3.0 wt% CNPs dispersed in PVA. The as‐prepared samples were characterized using various characterization techniques. The resulting nanocomposites proved to possess homogeneity and better mechanical, thermal, optical, and flame‐retardant properties than pure PVA. Most of the CNPs with average particle size ≤100 nm were homogeneously dispersed in the PVA matrix showing fluorescence in the violet color zone. The crystallinity of the nanocomposites show a decline in the diffraction intensity as compared to pure PVA which results from the dwelling of CNPs inside the gaps of stacked‐layer chains of PVA. The mechanical properties of nanocomposites indicated enhancement in toughness, elastic modulus and tensile strength with an increase in CNPs contents. The assessment for flame‐retardant properties was carried out through cone calorimetry. The results show a decrease in both total heat release rate (THRR) and peak heat release rate (pHRR) of the resulting nanocomposites as compared to pure PVA. The superior properties of the CNPs/PVA composites stemmed from the good interfacial bonding between the CNPs and PVA matrix.

An amperometric type sensor whose active layer is derived from a tetra core-substituted organic semiconductor, naphthalene diimide (NDI-CN4), has been evaluated for ammonia gas (3, 6, 25 and 50 ppm)...

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