Aiming to overcome both the structural and commercial limitations of flexible thermoelectric power generators, an efficient room‐temperature aqueous selenization reaction that can be completed in air within less than 1 min, to directly fabricate thin β‐Ag2Se films consisting of perfectly crystalline and large columnar grains with both in‐plane randomness and out‐of‐plane [201] preferred orientation, is designed. A high power factor (PF) of 2590 ± 414 µW m−1 K−2 and a figure‐of‐merit (zT) of 1.2 ± 0.42 are obtained from a sample with a thickness of ≈1 µm. The maximum output power density of the best 4‐leg thermoelectric generator sample reach 27.6 ± 1.95 and 124 ± 8.78 W m−2 at room temperature with 30 and 60 K temperature differences, respectively, which may be useful in future flexible thermoelectric devices.
Two-dimensional (2D) van-der-Waals (vdW) layered ferroelectric semiconductors are highly desired for in-memory computing and ferroelectric photovoltaics or detectors. Beneficial from the weak interlayer vdW-force, controlling the structure by interlayer twist/translation or doping is an effective strategy to manipulate the fundamental properties of 2D-vdW semiconductors, which has contributed to the newly-emerging sliding ferroelectricity. Here, we report unconventional room-temperature ferroelectricity, both out-of-plane and in-plane, in vdW-layered γ-InSe semiconductor triggered by yttrium-doping (InSe:Y). We determine an effective piezoelectric constant of ∼7.5 pm/V for InSe:Y flakes with thickness of ∼50 nm, about one order of magnitude larger than earlier reports. We directly visualize the enhanced sliding switchable polarization originating from the fantastic microstructure modifications including the stacking-faults elimination and a subtle rhombohedral distortion due to the intralayer compression and continuous interlayer pre-sliding. Our investigations provide new freedom degrees of structure manipulation for intrinsic properties in 2D-vdW-layered semiconductors to expand ferroelectric candidates for next-generation nanoelectronics.
The anisotropy in the crystal structure plays a striking role in the optical, electrical and thermal properties of the condensed matter. Here, we investigate the in-plane vibrational anisotropy in two-dimensional...
Antiferroelectric thin-film capacitors with ultralow
remanent polarization
and fast discharge speed have attracted extensive attention for energy
storage applications. A multilayer heterostructure is considered to
be an efficient approach to enhance the breakdown strength and improve
the functionality. Here, we report a high-performance multilayer heterostructure
(PbZrO3/PbTiO3)
n
with a maximum recoverable energy storage density of 36.4 J/cm3 due to its high electric breakdown strength (2.9 MV/cm) through
the heterostructure strategy. The positive effect of interfacial blockage
and the negative effect of local strain defects competitively affect
the breakdown strength, showing an inflection point at n = 3. The atomic-scale characterizations reveal the underlying microstructure
mechanism of the interplay between the heterointerface dislocations
and the decreased energy storage performance. This work offers the
potential of well-designed multilayers with high energy storage performance
through heterostructure engineering.
Nanoscale tellurium (Te) materials are promising for advanced optoelectronics owing to their outstanding photoelectrical properties. In this work, high-performance optoelectronic nanodevice based on a single tellurium nanotube (NT) was prepared by focused ion beam (FIB)-assisted technique. The individual Te NT photodetector demonstrates a high photoresponsivity of 1.65 × 104 AW−1 and a high photoconductivity gain of 5.0 × 106%, which shows great promise for further optoelectronic device applications.
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