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We studied the use of carbon-nanotube-(CNT)-based strain sensors as components of a textilebased, wearable sensing system for real-time motion detection. In the stretchable sensor, millimeter-long multiwalled CNTs (MWCNTs) are unidirectionally aligned and sandwiched between elastomer layers. We synthesized urethane resin to make the elastomer, which exhibits low elasticity and an affinity for human skin. The aligned CNT layer was formed by stacking CNT webs drawn from a spinnable CNT forest. The stretchable sensor can be stretched up to 200% and exhibits a short sensing delay of less than 15 ms. The gauge factor exceeds 10, which indicates high sensitivity. Moreover, the device is thin and as soft as human skin. The demonstrated flexibility and conformable nature make this material ideally suited for wearable sensors, specifically for a textile-based, wearable, real-time, human body motion-sensing application.

GaN nanostructures were prepared on Si(111) by a hot-wall epitaxy technique employing the modified two-step growth method. Isolated hexagonal pillar-like GaN nanostructures (GaN nanopillars) with the typical diameter, height, and density of 200–300nm, 0.5–1μm, and 3–4×108cm−2, respectively, are self-organized without intentional pre-processing to the Si substrate. The photoluminescence and cathodoluminescence (CL) measurements show the strong near-band-edge emissions without the yellow band at room temperature. Stronger CL is obtained from the GaN nanopillars in comparison to single-crystalline GaN. The obtained strong CL is related to high crystal quality of the dislocation-free GaN nanopillars.

Electron-transport layer (ETL)/perovskite interface modification plays a key task for producing efficient planar perovskite solar cells (PSCs). In this study, interfacial modification of compact TiO2 using novel, one-step hydrothermally synthesized single-crystalline anatase (AT) titania nanoparticles (TiO2 NPs) (average diameter = 6–10 nm) was applied as an ETL bilayer to enhance the efficient charge generation and extraction and eliminate the electron–hole recombination ratio. We report here an easy approach for enhancing the performance of planar PSCs by introducing a compact TiO2/AT TiO2 NPs bilayer through spray pyrolysis (SP) deposition and spin-coating (SC) techniques, respectively. The enhanced performance of the devices with an SP-TiO2/SC-AT TiO2 NPs bilayer facilitated more efficient electron transport, charge extraction, and low interfacial recombination. Ultimately, the best device had a 17.05% power conversion efficiency resulting from the significant decrease in J–V hysteresis, presenting almost a 12% performance improvement compared to the TiO2 only layer-based counterpart. Thus, the present study provides an important advance to the design of photovoltaic devices with respect to charge transport and electron–hole recombination.