Hybrid halide perovskites emerging as a highly promising class of functional materials for semiconductor optoelectronic applications have drawn great attention from worldwide researchers. In the past few years, prominent nonlinear optical properties have been demonstrated in perovskite bulk structures indicating their bright prospect in the field of nonlinear optics (NLO). Following the surge of 3D perovskites, more recently, the low‐dimensional perovskites (LDPs) materials ranging from two‐, one‐, to zero‐dimension such as quantum‐wells or colloidal nanostructures have displayed unexpectedly attractive NLO response due to the strong quantum confinement, remarkable exciton effect, and structural diversity. In this perspective, the current state of the art is reviewed in the field of NLO for LDP materials. The relationship between confinement effect and NLO is analyzed systematically to give a comprehensive understanding of the function of dimension reduction. Furthermore, future directions and challenges toward the improvement of the NLO in LDP materials are discussed to provide an outlook in this rapidly developing field.
Although zinc‐based batteries are promising candidates for eco‐friendly and cost‐effective energy storage devices, their performance is severely retarded by dendrite formation. As the simplest zinc compounds, zinc chalcogenides, and halides are individually applied as a Zn protection layer due to high zinc ion conductivity. However, the mixed‐anion compounds are not studied, which constrains the Zn2+ diffusion in single‐anion lattices to their own limits. A heteroanionic zinc ion conductor (ZnyO1−xFx) coating layer is designed by in situ growth method with tunable F content and thickness. Strengthened by F aliovalent doping, the Zn2+ conductivity is enhanced within the wurtzite motif for rapid lattice Zn migration. ZnyO1−xFx also affords zincophilic sites for oriented superficial Zn plating to suppress dendrite growth. Therefore, ZnyO1−xFx‐coated anode exhibits a low overpotential of 20.4 mV for 1000 h cycle life at a plating capacity of 1.0 mA h cm−2 during symmetrical cell test. The MnO2//Zn full battery further proves high stability of 169.7 mA h g−1 for 1000 cycles. This work may enlighten the mixed‐anion tuning for high‐performance Zn‐based energy storage devices.
Multiple ultrashort laser pulses are widely used in optical spectroscopy, optoelectronic manipulation, optical imaging and optical signal processing etc. The laser pulse multiplication, so far, is solely realized by using the optical setups or devices to modify the output laser pulse from the optical gain medium. The employment of these external techniques is because the gain medium itself is incapable of modifying or multiplying the generated laser pulse. Herein, with single femtosecond laser pulse excitation, we achieve the double-pulsed stimulated emission with pulse duration of around 40 ps and pulse interval of around 70 ps from metalhalide perovskite multiple quantum wells. These unique stimulated emissions originate from one fast vertical and the other slow lateral high-efficiency carrier funneling from lowdimensional to high-dimensional quantum wells. Furthermore, such gain medium surprisingly possesses nearly Auger-free stimulated emission. These insights enable us a fresh approach to multiple the ultrashort laser pulse by gain medium.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.