•Sr-doped SnO2 nanofibers have been successfully obtained via electrospinning and calcination.•Sr-doped SnO2 nanofibers show high response and rapid response/recovery behavior to ethanol.•Sr-doped SnO2 nanofibers exhibit good discriminative ability to ethanol from acetone.•Sr-doped SnO2 nanofibers display good selectivity to some reducing gases.We demonstrated a new metal oxides based chemiresistor (MOC), which exhibits fast response/recovery behavior, large sensitivity, and good selectivity to ethanol, enabled by Sr-doped SnO2 nanofibers via simple electrospinning and followed by calcination. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS) were carefully used to characterize their morphology, structure, and composition. The ethanol sensing performances based on Sr-doped SnO2 nanofibers were investigated. Comparing with the pristine SnO2 nanofibers, enhanced ethanol sensing performances (more rapid response/recovery behavior and larger response values) have been achieved owing to the basic SnO2 surface caused by Sr-doping, whereas the acetone sensing performances have been weakened. Thus, good discriminative ability to ethanol from acetone has been realized. Additionally, Sr-doped SnO2 nanofibers also exhibit good selectivity.

This paper describes the exploration of a synergic effect within n-type inorganic–p-type organic nano-hybrids in gas sensors. One-dimensional (1D) n-type SnO2–p-type PPy composite nanofibers were prepared by combining the electrospinning and polymerization techniques, and taken as models to explore the synergic effect during the sensing measurement. Outstanding sensing performances, such as large responses and low detection limits (20 ppb for ammonia) were obtained. A plausible mechanism for the synergic effect was established by introducing p–n junction theory to the systems. Moreover, interfacial metal (Ag) nanoparticles were introduced into the n-type SnO2–p-type PPy nano-hybrids to further supplement and verify our theory. The generality of this mechanism was further verified using TiO2–PPy and TiO2–Au–PPy nano-hybrids. We believe that our results can construct a powerful platform to better understand the relationship between the microstructures and their gas sensing performances.

One-dimensional (1D) semiconducting nanostructures, as both interconnections and functional units in fabricating electronic, biological/chemical sensors, optoelectronic, electrochemical, and electromechanical devices, attract immense interest. However, all those 1D semiconducting nanostructures are sensitive to both volatile organic compounds (VOFs) and relative humidity (RH), causing the instability of those devices operated in air (except in biological/chemical sensors). Herein, we demonstrated an effective route to not only stabilize 1D semiconducting nanostructures in air but also maintain their electrical properties by constructing 1D isomeric semiconducting nanorods on 1D semiconducting nanostructures to form 1D isomeric and hierarchical semiconducting nanostructures. 1D isomeric and hierarchical TiO2 nanostructures (IHTNs) were chosen as a model, both excellent air stability and good electrical properties can be achieved. With such IHTNs as building blocks, a stable field-effect transistor has been realized.

A novel one-dimensional (1D) polymeric heterojunction based on weak-acceptor-polyacrylonitrile/donor-polyaniline core–shell nanofibers is designed for photoconductive devices through electrospinning followed by solution polymerization. Such 1D heterojunction can not only provide the large phase-separated nano-interface for effective charges separation between the cores and shells, but also facilitate the mass charge collection and transport along the nanofiber structure, resulting in greatly enhanced optoelectronic performance. The short 0.1 s response time upon irradiation is among the fastest values, as is the short 0.1 s time for return to the non-irradiated state. Extremely high on–off resistivity ratios (exceeding 4 × 104) can be obtained under the drive voltage of only 0.01 V, indicating the energy required for electrical input is very small. Higher drive voltages (a modest 10 V) can provide a very high responsivity of 20 A W−1 driven by 365 nm UV irradiation. Moreover, the as-prepared flexible photoconductive device maintains performance even after bending fatigue tests for bending angles as large as 180°.Graphical abstractA novel polymeric heterojunction based on weak-acceptor-polyacrylonitrile/donor-polyaniline core-shell nanofibers is designed for photoconductive application through electrospinning followed by solution polymerization. The heterojunction provides phase-separated nano-interface for charges separation between the cores and shells, and quasi-one-dimensional charge collection and transport along the nanofiber structure, resulting in greatly enhanced optoelectronic performance.Highlights► The first example of all-polymeric 1D core–shell acceptor–donor heterojunction for photoelectronics. ► Phase-separated nano-interface for charges separation between the cores and shells. ► Quasi-one-dimensional charge collection and transport along the nanofibers. ► The as-prepared devices can bear fatigue tests without degradation of device performances. ► Excellent photoconductive performance suggests applications viability.

This paper describes the exploration of a synergic effect within n-type inorganic–p-type organic nano-hybrids in gas sensors. One-dimensional (1D) n-type SnO2–p-type PPy composite nanofibers were prepared by combining the electrospinning and polymerization techniques, and taken as models to explore the synergic effect during the sensing measurement. Outstanding sensing performances, such as large responses and low detection limits (20 ppb for ammonia) were obtained. A plausible mechanism for the synergic effect was established by introducing p–n junction theory to the systems. Moreover, interfacial metal (Ag) nanoparticles were introduced into the n-type SnO2–p-type PPy nano-hybrids to further supplement and verify our theory. The generality of this mechanism was further verified using TiO2–PPy and TiO2–Au–PPy nano-hybrids. We believe that our results can construct a powerful platform to better understand the relationship between the microstructures and their gas sensing performances.

One-dimensional (1D) semiconducting nanostructures, as both interconnections and functional units in fabricating electronic, biological/chemical sensors, optoelectronic, electrochemical, and electromechanical devices, attract immense interest. However, all those 1D semiconducting nanostructures are sensitive to both volatile organic compounds (VOFs) and relative humidity (RH), causing the instability of those devices operated in air (except in biological/chemical sensors). Herein, we demonstrated an effective route to not only stabilize 1D semiconducting nanostructures in air but also maintain their electrical properties by constructing 1D isomeric semiconducting nanorods on 1D semiconducting nanostructures to form 1D isomeric and hierarchical semiconducting nanostructures. 1D isomeric and hierarchical TiO2 nanostructures (IHTNs) were chosen as a model, both excellent air stability and good electrical properties can be achieved. With such IHTNs as building blocks, a stable field-effect transistor has been realized.