Bipolar resistive switching using organic molecule is very promising for memory applications owing to their advantages, such as simple device structure, low manufacturing cost, stability, and flexibility. Herein we report Langmuir–Blodgett (LB) and spin-coated-film-based bipolar resistive switching devices using organic material 1,4-bis­(di­(1H-indol-3-yl)­methyl)­benzene (Indole1). The pressure–area per molecule isotherm (π–A), Brewster angle microscopy (BAM), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were used to formulate an idea about the organization and morphology of the organic material onto thin films. On the basis of the device structure and measurement protocol, it is observed that the device made up of Indole1 shows nonvolatile resistive random access memory (RRAM) behavior with a very high memory window (∼106), data sustainability (5400 s), device yield (86.7%), and repeatability. The oxidation–reduction process and electric-field-driven conduction are the keys behind such switching behavior. Because of very good data retention, repeatability, stability, and a high device yield, the switching device designed using compound Indole1 may be a potential candidate for memory applications.

Interest in biodegradable and transient electronics is gaining due to their potential use in green electronics, biomedical devices, and sustainable solutions for ewastes. In this paper we employed Protamine Sulfate (PS) as the active layer to demonstrate biodegradable transient resistive memory devices. The Au/PS/ITO device exhibits nonvolatile resistive switching with write-once-read-many (WORM) memory behavior. The observed WORM memory performance was very good with high memory window (4.57× 10 3 ), data retention (experimentally >10 6 s, extrapolated >10 8 s), device yield (∼87.5%), read endurance (>3.6 × 10 4 ), and device stability (>210 days). Bias induced charge trapping followed by conducting filament formation was the key to such switching. The electronic as well as optical behavior completely disappeared after 8 min of dissolution of the device in aqueous solution. As a whole this work suggests that the PS based WORM memory device may be a potential candidate toward designing biodegradable transient memory devices.

Complementary resistive switching (CRS) devices are more advantageous compared to bipolar resistive switching (BRS) devices for memory applications as they can minimize the sneak path problem observed in the case of BRS having a crossbar array structure. Here, we report the CRS behavior of 1,4bis(di(1H-indol-3-yl)methyl)benzene (Indole1) molecules. Our earlier study revealed that Au/Indole1/Indium tin oxide (ITO) devices showed BRS under ambient conditions. However, the present investigations revealed that when the device is exposed to 353 K or higher temperatures, dynamic evolution of the Au/ Indole1/ITO device from BRS to CRS occurred with a very good memory window (∼10 3 ), data retention (5.1 × 10 3 s), stability (50 days), and device yield (∼ 60%). This work explores the application possibility of indole derivatives toward future ultradense resistive random access memory.

Polydiacetylenes have gained increasing attention as promising smart materials owing to their brilliant blue-to-red color transition in response to various microenvironmental perturbations. In this communication, we report a paper-based naked-eye colorimetric sensor array comprising 10, 12-tricosadiynoic acid (TCDA) and N-1-hexadecyl imidazole derivatives. Sensor arrays were prepared onto a filter paper using the suction technique, followed by UV irradiation. In this sensor system, the clay material hectorite was used as the host/support to enhance the mechanical stability of the paper-based sensor. Both the TCDA-clay and TCDA-clay-N-1-hexadecyl imidazole sensors were studied to sense 12 different volatile organic compounds (VOCs). Interestingly, the TCDA-clay sensor responded to 7 VOCs, whereas the TCDA-clay-N-1-hexadecyl imidazole sensor responded to all 12 VOCs. The presence of N-1-hexadecyl imidazole was advantageous with respect to response time, concentration, and the number of VOCs. Interestingly, the designed sensors also showed distinct response toward gasoline and the presence of kerosene in gasoline. Applications of the designed sensors toward the pollution level of car exhaust have also been demonstrated successfully.

In the present communication, we have investigated the interaction between a biomembrane component 1,2-dioleoyl- sn -glycero-3-phosphocholine (DOPC) and a coagulating protein protamine sulfate (PS) using the Langmuir–Blodgett (LB) technique. The π– A isotherm, π– t characteristics, and analysis of isotherm curves suggested that PS strongly interacted with DOPC, affecting the fluidity of the DOPC layer. Electrical characterization indicates that PS as well as the PS–DOPC film showed resistive switching behavior suitable for Write Once Read Many (WORM) memory application. Trap-controlled space charge-limited conduction (SCLC) was the key mechanism behind such observed switching. The presence of DOPC affected the SCLC process, leading to lowering of threshold voltage ( V Th ), which is advantageous in terms of lower power consumption.

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Development of biocompatible and biodegradable information storage could be one of the major strides toward the advancement of the next-generation eco-friendly electronics. Locally available leaves of Ipomoea carnea (IC) are employed to design a nonvolatile resistive memory device having the configuration Au/IC/ITO. The IC-based memory device is found to have back-to-back Schottky behavior. The memory device exhibits a very good ON/OFF ratio (∼102), device yield (78%), reproducibility (≈32 cycles), and good physical stability (>360 days). Upon UV irradiation, the device performance improves in terms of a higher device yield (82%) and a larger memory window (104). Space charge-limited conduction, Schottky emission (SE), and metallic filament formation were the key behind the conduction mechanism for such observed switching behavior. Atomic force microscopy measurements have also been carried out in order to visualize the conduction filament in the IC-based resistive device. Temperature-dependent investigations confirmed that the gold filament and oxygen vacancy filament play an important role in the conduction mechanism. Based on the I–V characteristics as well as the data storage nature, it has been proposed that IC-based switching devices may be utilized to design rewritable read-only memory devices. This is an improvement of conventional write-once-read-many memory.