A Giant Tunable Piezoelectric Performance in Two‐dimensional In2Se3 via Interface Engineering

Abstract Two‐dimensional (2D) layered piezoelectric materials have attracted enormous interest, which leads to wide applications in stretchable electronic, energy and biomedicine. The piezoelectric properties of 2D materials are mainly modulated by strain, thickness, defect engineering and stacked structure. However, the tunability of piezoelectric properties is typically limited by the small variation within one order of magnitude. It is challenging to obtain high tunable piezoelectric properties of 2D materials. Here, this study reports that the out‐of‐plane piezoelectric properties of 2D van der Waals In2Se3 are significantly manipulated using interface engineering. The variation value of piezoelectric properties is above two orders of magnitude, giving rise to the highest variation value in the 2D piezoelectric materials system. In particular, the 2D materials In2Se3 can be directly fabricated onto silicon substrate, which suggests its compatibility with the state‐of‐the‐art silicon semiconductor technology. Combining the experimental and computational results, this study reveals that the ultrahigh tunable piezoelectric properties result from the interface charge transfer effect. The work opens the door to design and modulate the unprecedented applications of atomic‐scale smart and multifunctional devices

Frequency converting and digital modulation of light derived from lanthanide for signal encoding and logic computing

Abstract Modulation of light underpins a central part of modern optoelectronics. Conventional optical modulators based on refractive‐index and absorption variation in the presence of an electric field serve as the workhorse for diverse photonic technologies. However, these approaches based on electro‐refraction or electro‐absorption effect impose limitations on frequency converting and signal amplification. Lanthanide‐activated phosphors offer a promising platform for nonlinear frequency conversion with an abundant spectrum. Here, we propose a novel approach to achieve frequency conversion and digital modulation of light signal by coupling lanthanide luminescence with an electrically responsive ferroelectric host. The technological benefits of such paradigm‐shifting solution are highlighted by demonstrating a quasi‐continuous and enhancement of the lanthanide luminescence. The ability to locally manipulate light emission can convert digital information signals into visible waveforms, and visualize electrical logic and arithmetic operations. The proof‐of‐concept device exhibits perspectives for developing light‐compatible logic functions. These results pave the way to design more controllable lanthanide photonics with desired opto‐electronic coupling