To date, the synthesis of crystalline ZnO nanostructures was often performed under high temperatures and/or high pressures with tiny output, which limits their commercial applications. Herein, we report the progress on synthesizing single-crystalline ZnO nanosheets under ambient conditions (i.e., room temperature (RT) and atmospheric pressure) based on a sonochemistry strategy. Furthermore, their controllable growth is accomplished by adjusting the pH values of solutions, enabling the tailored crystal growth habits on the polar-charged faces of ZnO along c-axis. As a proof of concept for their potential applications, the ZnO nanosheets exhibit highly efficient performance for sensing ammonia at RT, with ultrahigh sensitivity (S = 610 at 100 ppm), excellent selectivity, rapid detection (response time/recover time = 70 s/4 s), and outstanding detection limit down to 0.5 ppm, superior to those of all pure ZnO nanostructures and most ZnO-based composite counterparts ever reported. The present work might open a door for controllable production of ZnO nanostructures under mild conditions, and facilitate the exploration of modern gas sensors for detecting gaseous molecules at RT, which underscores their potential toward practical applications in opto-electronic nanodevices.

In the present work, we report the growth of all-inorganic perovskite nanorings with dual compositional phases of CsPbBr₃ and CsPb₂Br₅ via a facile hot injection process. The self-coiling of CsPbBr₃-CsPb₂Br₅ nanorings is driven by the axial stress generated on the outside surface of the as-synthesized nanobelts, which results from the lattice mismatch during the transformation of CsPbBr₃ to CsPb₂Br₅. The tailored growth of nanorings could be achieved by adjusting the key experimental parameters such as reaction temperature, reaction time and stirring speed during the cooling process. The photoluminescence intensity and quantum yield of nanorings are higher than those of CsPbBr₃ nanobelts, accompanied by a narrower full width at half maximum (FWHM), suggesting their high potential for constructing self-assembled optoelectronic nanodevices.

High-performance solar-blind UV (ultraviolet) photodetectors (PDs) based on low-dimension semiconducting nanostructures with high sensitivity, excellent cycle stability, and the ability to operate in harsh environments are critical for solar observations, space communication, UV astronomy, and missile tracking. In this study, TiO₂-ZnTiO₃ heterojunction nanowire-based PDs are successfully developed and used to detect solar-blind UV light. A photoconductive analysis indicates that the fabricated PDs are sensitive to UV illumination, with high sensitivity, good stability, and high reproducibility. Further analysis indicates that the rich existence of grain boundaries within the TiO₂-ZnTiO₃ nanowire can greatly decrease the dark current and recombination of the electron-hole pairs and thereby significantly increase the device's photosensitivity, spectra responsivity (1.1 × 10⁶), and external quantum efficiency (4.3 × 10⁸ %). Moreover, the PDs exhibit good photodetective performance with fast photoresponse and recovery and excellent thermal stability at temperatures as high as 175 ℃. According to these results, TiO₂-ZnTiO₃ heterojunction nanowires exhibit great potential for applications in high-performance optical electronics and PDs, particularly next-generation photodetectors with the ability to operate in harsh environments.