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Well-defined poly(2,6-dimethyl-4,4 1 -phenylene oxide)-g-poly(styrenesulfonic acid) (PPO-g-PSSA) graft copolymer was synthesized via living radical polymerization. For the graft copolymer, poly(2,6-dimethylphenylene oxide) (PPO) was brominated first, and the brominated PPO (PPO-Br) was used as a macroinitiator in the atom transfer radical polymerization (ATRP) of styrenesulfonic acid sodium salt. The number of grafts per PPO chain and the molecular weight of the graft were controlled by adjusting the degree of bromination, and conversion in ATRP, respectively. The graft copolymers obtained were transformed into proton exchange membranes for direct methanol fuel cell (DMFC) application. The performance of the membranes was measured in terms of water uptake, proton conductivity, methanol permeability, and thermal stability. The water uptake, ion exchange capacity (IEC), and proton conductivity of the membranes increased with PSSA block content. Very low methanol permeability and good proton conductivity were observed by adjusting grafting frequency and PSSA block content.

Recently, attempts to overcome the physical limits of memory devices have led to the development of promising materials and architectures for nextgeneration memory technology. The selector device is one of the essential ingredients of high-density stacked memory systems. However, complicated constituent deposition conditions and thermal degradation are problematic, even with effective selector device materials. Herein, we demonstrate the highly stable and low-threshold voltages of vanadium pentoxide (V 2 O 5 ) nanosheets synthesized by facile chemical vapor deposition, which have not been previously reported on the threshold switching (TS) properties. The electrons occupying trap sites in poly-crystalline V 2 O 5 nanosheet contribute to the perfectly symmetric TS feature at the bias polarity and low-threshold voltages in V 2 O 5 , confirmed by high-resolution transmission electron microscopy measurements. Furthermore, we find an additional PdO interlayer in V 2 O 5 nanodevices connected with a Pd/Au electrode after thermal annealing treatment. The PdO interlayer decreases the threshold voltages, and the I on /I off ratio increases because of the increased trap density of V 2 O 5 . These studies provide insights into V 2 O 5 switching characteristics, which can support low power consumption in nonvolatile memory devices.

Most organic thin film‐based phototransistors exhibit an increase in current under illumination owing to the trapped photogenerated minority charge carriers, which enhance the accumulation of majority carriers in the semiconductor layer of the device. Recent research reveals that, on employing a unique active layer structure, phototransistor devices exhibit abnormal photoresponse behaviors under certain conditions: hole‐dominated current decreases under illumination and shows an anomalous dependence on irradiance. The current decreases with increasing irradiance. When the irradiance is increased further, a moderate current increase is observed. Under a constant negative bias, when a discrete light pulse is turned on, the current decreases sharply and then slowly increases to saturation in the beginning and it starts to increase when illumination is ceased. These anomalies are analyzed, and the changes in current are modeled using a mathematical model based on the simultaneous trapping and release of both photogenerated holes and electrons.

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