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Energy harvesting from extremely low frequency magnetic fields using magneto‐mechano‐electric (MME) harvesters enables wireless power transfer for operating Internet of Things (IoT) devices. The MME harvesters are designed to resonate at a fixed frequency by absorbing AC magnetic fields through a composite cantilever comprising of piezoelectric and magnetostrictive materials, and a permanent magnetic tip mass. However, this harvester architecture limits power generation because volume of the magnetic end mass is closely coupled with the resonance frequency of the device structure. Here, a method is demonstrated for maintaining the resonance frequency of the MME harvesters under all operating conditions (e.g., 60 Hz, standard frequency of electricity in many countries) while simultaneously enhancing the output power generation. By distributing the magnetic mass over the beam, the output power of the harvester is significantly enhanced at a constant resonance frequency. The MME harvester with distributed forcing shows 280% improvement in the power generation compared with a traditional architecture. The generated power is shown to be sufficient to power eight different onboard sensors with wireless data transmission integrated on a drone. These results demonstrate the promise of MME energy harvesters for powering wireless communication and IoT sensors. [ABSTRACT FROM AUTHOR]

Abstract: Internet of Things (IoT) is driving the development of new generation of sensors, communication components, and power sources. Ideally, IoT sensors and communication components are expected to be powered by sustainable energy source freely available in the environment. Here, a breakthrough in this direction is provided by demonstrating high output power energy harvesting from very low amplitude stray magnetic fields, which exist everywhere, through magnetoelectric (ME) coupled magneto‐mechano‐electric (MME) energy conversion. ME coupled MME harvester comprised of multiple layers of amorphous magnetostrictive material, piezoelectric macrofiber composite, and magnetic tip mass, interacts with an external magnetic field to generate electrical energy. Comprehensive experimental investigation and a theoretical model reveal that both the magnetic torque generated through magnetic loading and amplification of magneto‐mechanical vibration by ME coupling contributes toward the generation of high electrical power from the stray magnetic field around power cables of common home appliances. The generated electrical power from the harvester is sufficient for operating microsensors (gyro, temperature, and humidity sensing) and wireless data transmission systems. These results will facilitate the deployment of IoT devices in emerging intelligent infrastructures. [ABSTRACT FROM AUTHOR]

Conventional semi‐transparent perovskite solar cells (ST‐PSCs) generally exhibit inferior performance and stability relative to opaque PSCs. However, a comprehensive understanding of the origins of inferior performance and stability of ST‐PSCs and a practical solution to these challenges are both lacking. Here, it is shown for the first time that lithium ions from a lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)‐doped 2,2′,7,7′‐tetrakis[N,N‐di(4‐methoxyphenyl)amino]−9,9′‐spirobifluorene (Spiro‐MeOTAD) hole‐transport layer (HTL) can diffuse into the molybdenum trioxide buffer layer at their interface, yielding ST‐PSCs with lower efficiency and accelerated degradation. It is also demonstrated that this undesired Li‐ion diffusion can be avoided by HTL surface modification with stable lithium oxides. Using this approach, the constructed ST‐PSC exhibits a new record power conversion efficiency (PCE) of 22.02% (21.68% certified) and a fill factor of >80%, with >99% shelf‐stability after 400 h and >99% operational stability for 240 h, which clears away this longstanding limitation of the performance and stability of ST‐PSCs. This strategy is also applied to fabricate four‐ and two‐terminal perovskite/silicon tandem solar cells with bifacial equivalent efficiencies of 31.5% and 26.34%, respectively, at 20% albedo. [ABSTRACT FROM AUTHOR]

In the article "Mitigating Intrinsic Interfacial Degradation in Semi-Transparent Perovskite Solar Cells for High Efficiency and Long-Term Stability," the authors discuss a new internal degradation mechanism in semi-transparent perovskite solar cells. They found that when the hole-transport layer surface is enriched with LiTFSI, lithium ions diffuse into the MoO3 layer, leading to continuous degradation of the device. However, the conversion of LiTFSI into stable lithium oxides (LixOy) improves both the efficiency and stability of the device by effectively mitigating Li diffusion. This research provides valuable insights for the development of more efficient and stable perovskite solar cells. [Extracted from the article]

Biomacromolecular pigments, such as melanin, play an essential role in the survival of all living beings. Melanin absorbs sunlight and transforms it into heat, which is crucial for avoiding damage to skin cells. Light absorption produces excited electrons, which could either fall back to ground states by releasing the heat (photothermal effect) and/or light (photoluminescence), or stay at higher energy levels within its lifetime period, which can be captured through external electronic circuitry (photovoltaic effect). In this study, it is demonstrated that the combination of melanin with halide perovskite light absorber in the form of a composite exhibits high absorbance from the UV to NIR region in the solar spectrum. And the composite displays significantly reduced photoluminescence and minimized density of residual excited states (verified by photovoltaic measurement) owing to the significantly enhanced nonradiant quenching by the melanin. As a result, the composite shows an ultrahigh solar‐thermal quantum yield of 99.56% and solar‐thermal conversion efficiency of ≈81% under one‐sun illumination (AM1.5), which is superior to typical carbon materials such as graphene (≈70%). By coating the photothermal composite film on the hot‐side of thermoelectric devices, a 7000% increase in output power as compared to the blank device under illumination is observed. [ABSTRACT FROM AUTHOR]

Metal–metalloid compounds have been paid much attention as new high‐performance water oxidation catalysts due to their exceptional durability for water oxidation in alkaline media originating from the multi‐dimensional covalent bonding of the metalloid with the surrounding metal atoms. However, compared to the excellent stability, a relatively low catalytic activity of metal‐metalloids often limits their practical application as high‐performance water oxidation catalysts. Here, for the first time, disclosed is a novel self‐templating strategy combined with atomic layer deposition (ALD) to design the electrochemically active and stable quaternary metal boride (vanadium‐doped cobalt nickel boride, VCNB), hollow nanoprism by inducing electronic double layers on the surface. The incorporation of V in a double‐layered structure can substantially increase the number of surface active sites with unsaturated electronic structure. Furthermore, the induced electronic double layers of V can effectively protect the dissolution of the surface active sites. In addition, density functional theory (DFT) calculations reveal that the impressive water oxidation properties of VCNB originate from the synergetic physicochemical effects of the different metal elements, Co and B as active sites, Ni as a surface electronic structure modifier, and V as a charge carrier transporter and supplier. Electronically double‐layered structure in quaternary metal–metalloid hollow nanoprism can substantially enhance water oxidation activity as well as stability of metal–metalloid in alkaline media. [ABSTRACT FROM AUTHOR]

In article number 1803799, Heechae Choi, Yong‐Chae Chung, Taeseup Song and co‐workers report that an electronically double‐layered structure in quaternary metal‐metalloid hollow nanoprism can substantially enhance water oxidation activity as well as the stability of metalmetalloids in alkaline media. Double‐layered vanadium enhances charge transfer at the surface as well as the carrier concentration at the Fermi level. Furthermore, it can also prevent the surrounding metal atoms from leaching out and, as a result, substantially improves electrocatalytic stability of quaternary metal‐metalloid compounds for water oxidation in an alkaline medium. [ABSTRACT FROM AUTHOR]