Color manipulation of intense multiluminescence from CaZnOS:Mn2+ has been realized by adjusting Mn2+ concentration. Not only the photoluminescence (PL) of Mn2+ emission from 4T1(4G) to 6A1(6S) shows a red shift from yellow to red with increasing Mn2+ concentration, which is in contrast to the fixed PL emission reported by Hintzen et al. (Chem. Mater., 2009), but also mechanoluminescence (ML) and cathodoluminescence (CL) have a similar variation. More attractively, the brightness of multiluminescence is surprisingly intense for all the CaZnOS:Mn2+ with a large-scale Mn2+ doping (0.1–10 mol %). Based on the investigation of crystal field, various spectral results, and PL lifetimes, the red-shift mechanism of multiluminescence reported here has been proposed to arise from the exchange interaction effect of Mn2+ pairs at higher concentrations. In addition to correcting the previous misunderstanding on the emission of CaZnOS:Mn2+, these findings extend the tunable emission window, opening up new opportunities in multifunctional applications of PL, ML, and CL involving multicolor light sources, displays, and stress imaging, especially providing a novel resolution to design ML colors.

In this paper, we report a quick approach to self-assemble three-dimensional (3D) spongiform nanofiber stacks via electrospinning, which usually fabricates 2D non-woven fiber mats. Through controlling experimental conditions, cone-like polystyrene fiber stacks can be self-assembled on aluminum foil within 30 min. The stacks are able to reach a height of more than 10 cm. Moreover, conversion between the 3D fiber stack and 2D thin film can be controlled. The formation mechanism of the self-assembled fiber stacks and the influence of experimental conditions have also been explored. The 3D fiber stacks may be promising for applications in many fields such as tissue engineering, electrodes of battery, and filtration, etc.

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Stretchable strain sensors based on aligned microfibrous arrays of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)-poly(vinyl pyrrolidone) (PEDOT:PSS-PVP) with curled architectures have been fabricated by a novel reciprocating-type electrospinning setup with a spinneret in straightforward simple harmonic motion. The incorporation of PEDOT:PSS into PVP is confirmed by Raman spectra, which improves the room-temperature conductivity of the composite fibers (1.6 × 10(-5) S cm(-1)). Owing to the curled architectures of the as-spun fibrous polymer arrays, the sensors can be stretched reversibly with a linear elastic response to strain up to 4%, which is three times higher than that from electrospun nonwoven mats. In addition, the stretchable strain sensor with a high repeatability and durability has a gauge factor of about 360. These results may be helpful for the fabrication of stretchable devices which have potential applications in some fields such as soft robotics, elastic semiconductors, and elastic solar cells.

Electrospinning (e-spinning) still has certain limitations in flexible practicability because its conventional setup is usually quite bulky and excessively dependent on a plug (electric supply). In this article, we report on a battery-operated e-spinning apparatus (BOEA) based on miniaturization and integration. The new device gets liberated from the conventional heavy power supply, achieves the tight integration of functional parts and can be operated by a single hand due to its small volume (10.5 × 5 × 3 cm(3)) and light weight (about 120 g). Different polymers such as polyvinylpyrrolidone (PVP), polycaprolactone (PCL), polystyrene (PS), poly(lactic acid) (PLA) and poly(vinylidene fluoride) (PVDF) were electrospun into fibers successfully, which confirms the stable performance and good real-time control capability of the apparatus. These results demonstrate that the BOEA could be potentially applied in many fields, especially in biomedical fields such as skin damage, wound healing, rapid hemostasis, etc.