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In this study, (Cr1/3/Ta2/3) non-equivalent co-doped Bi4Ti3O12 (BIT) ceramics were prepared to solve the problem that high piezoelectric performance, high Curie temperature, and high-temperature resistivity could not be achieved simultaneously in BIT-based ceramics. A series of Bi4Ti3−x(Cr1/3Ta2/3)xO12 (x = 0–0.04) ceramics were synthesized by the solid-state reaction method. The phase structure, microstructure, piezoelectric performance, and conductive mechanism of the samples were systematically investigated. The B-site non-equivalent co-doping strategy combining high-valence Ta5+ and low-valence Cr3+ significantly enhances electrical properties due to a decrease in oxygen vacancy concentration. Bi4Ti2.97(Cr1/3Ta2/3)0.03O12 ceramics exhibit a high piezoelectric coefficient (d33 = 26 pC·N−1) and a high Curie temperature (TC = 687 ℃). Moreover, the significantly increased resistivity (ρ = 2.8×106 Ω·cm at 500 ℃) and good piezoelectric stability up to 600 ℃ are also obtained for this composition. All the results demonstrate that Cr/Ta co-doped BIT-based ceramics have great potential to be applied in high-temperature piezoelectric applications.

(Bi0.5Na0.5)TiO3 (BNT)-based lead-free piezoceramics exhibit excellent electric field-induced strain (electrostrain) properties, but often suffer from large hysteresis and poor fatigue resistance, which strongly limit their applications. Here, textured Nb5+-doped 0.8(Bi0.5Na0.5)TiO3–0.2(Bi0.5K0.5)TiO3 (0.8BNT–0.2BKT) ceramics with a high degree of texturing (~80%) were prepared by the reactive template grain growth (RTGG) method using Bi4Ti3O12 as a template. By the combination of donor doping in the B-site and the RTGG method, the electrostrain performance achieves a significant enhancement. A high electrostrain of 0.65% and a piezoelectric coefficient (d33*) of 1083 pm/V with reduced hysteresis at an electric field of 6 kV/mm are obtained. No electrostrain performance degradation is observed after unipolar electric field loading of 105 cycles, showing excellent fatigue endurance. These results indicate that the texturing BNT-based lead-free piezoceramics by the RTGG method is a useful approach to developing eco-friendly actuators.

Appropriate triboelectric material selection is vital to for high performance direct current triboelectric nanogenerator (DC-TENG). The authors here provide effective selection rules as guideline to select triboelectric materials for DC-TENG to reduce the trial-and-error cost for DC-TENG’s research.

Low charge density is the bottleneck for the applications of triboelectric nanogenerator (TENG). Here, the authors demonstrate a microstructure-designed direct-current TENG with rationally patterned electrode structure to enhance its effective charge density to a new milestone.

Triboelectric nanogenerators (TENGs) harvest ambient mechanical energy and convert it into electrical energy. Here, the authors couple surface polarization from contact electrification with dielectric polarization from a ferroelectric material in vacuum to dramatically enhance the TENG output power.

Abstract Emerging 2D electronic materials have shown great potential for regulating and controlling optoelectronic processes. A 2D ferroelectric semiconductor coupled with the piezo‐phototronic effect may bring unprecedented functional characteristics. Here, a heterojunction photodetector made of p‐Si/V‐doped‐ferroelectric‐ZnO 2D nanosheets (FESZ‐PD) is fabricated, and the ferroelectricity‐enhanced piezo‐phototronic effect on the photoresponse behavior of the FESZ‐PD is carefully investigated. By introducing the ferroelectricity and the piezo‐phototronic effect, improved current rectification performance is achieved and the photoresponse performance of the heterojunction is enhanced in a broad spectral range. The applied voltage bias during measurement naturally causes ferroelectric spontaneous polarizations to align, resulting in a change in band structure near the interface and the local piezo‐phototronic effect. The modulated energy band promotes the generation, separation, and transportation efficiency of photogenerated carriers greatly. Compared with the Si/ZnO 2D nanosheets photodetector without ferroelectricity under strain‐free conditions, the photoresponsivity R of the FESZ‐PD increases by 2.4 times when applying a −0.20‰ compressive strain at +1 V forward bias. These results confirm the feasibility of coupling the ferroelectricity with the piezo‐phototronic effect in 2D ferroelectric materials to enhance the photoresponse behavior, which provides a good way to enable the development of high‐performance electronic and optoelectronic devices.

This paper investigates a system of 0.93Bi0.5Na0.5TiO3–0.06BaTiO3–0.01K0.5Na0.5NbO3–xCuO (BNT–BT–KNN–xCuO, x=0−0.04mol.%) ceramics, which were fabricated by the conventional solid-state process through the granulation of vacuum freeze drier. The results show that the CuO doping made a significant enhancement on the piezoelectric properties of the BNT–BT–KNN ceramics. With the doping of CuO, the transition temperature between ferroelectric phase and ergodic relaxor state is reduced to near room temperature, resulting in pinched P–E loops and “sprout” shape S–E curves. For the composition with x=0.01, a high unipolar strain of 0.39% under 5kV/mm contributes a large d33∗∼780pm/V at room temperature, which is competitive with the other BNT-based ceramics.