Narrowband photodetector (NB‐PD) with selective light detection is critical for artificial vision and imaging. Intrinsic (optical‐filter‐free) NB‐PDs using conjugated organics or halide perovskite materials have been developed for eliminating the current complex filtering systems in NB‐PDs. However, the poor performance and external driving circuit of organic NB‐PDs as well as complex doping and uncontrollable recombination reactions in typical perovskite NB‐PDs have limited their applicational diversification. A p‐type self‐doped perovskite for intrinsic NB detection is reported which exhibits unique unbalanced electron–hole transfer kinetics. In conjunction with the optical field distribution, an unbalanced charge transport within the self‐doped perovskite triggers a wavelength‐dependent photo‐carrier collection, resulting in a novel spontaneous internal quantum efficiency narrowing mechanism. As a result, by reverting the device architectural polarity, an NB detection at a monochromic light of either red or UV is observed. Using such a revertible asymmetric device design, self‐powered NB‐PDs are successfully achieved. Briefly, the corresponding NB‐PDs exhibit excellent narrow response with a response window of ≈100 nm, high detectivity ≈1011 Jones, and fast response speed (f−3dB ≈ 60 kHz) at zero bias. These results demonstrate a new strategy of manipulating internal charge transport to realize power‐free and filter‐free intrinsic NB‐PDs.

A MME generator with a textured Fe–Ga alloy can generate over 1 mW power under a tiny magnetic field.

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, we provide a breakthrough in this direction by demonstrating high output power energy harvesting from very low amplitude stray magnetic field, which exists everywhere, through magnetoelectric (ME) coupled magneto-mechano-electric (MME) energy conversion. ME coupled MME harvester comprised of multiple layers of amorphous magnetostrictive material, piezoelectric macro-fiber composite (MFC), and magnetic tip mass, interacts with external magnetic field to generate electrical energy. Comprehensive experimental investigation and theoretical model reveal that both magnetic torque generated through magnetic loading and amplification of magneto-mechanical vibration by ME coupling contribute towards the generation of high electrical power from the stray magnetic field around power cable of common home appliances. The generated electrical power from the harvester was sufficient for operating micro-sensors (gyro, temperature, and humidity sensing) and wireless data transmission system. These results will facilitate the deployment of IoT devices in emerging intelligent infrastructures.

The rapid enhancement of the thermoelectric (TE) figure‐of‐merit (zT) in the past decade has opened opportunities for developing and transitioning solid state waste heat recovery systems. Here, a segmented TE device architecture is demonstrated in conjunction with heterogeneous material integration that results in high unicouple‐level conversion efficiency of 12% under a temperature difference of 584 K. This breakthrough is the result of success in fabricating bismuth telluride/half‐Heusler segmented TE unicouple modules using a “hot‐to‐cold” fabrication technique that provides significantly reduced electrical and thermal contact resistance. Extensive analytical and finite element modeling is conducted to provide an understanding of the nature of thermal transport and contributions arising from various thermal and physical parameters. Bismuth telluride/half‐Heusler based segmented thermoelectric generators (TEGs) can provide higher practical temperature difference with optimum average zT across the whole operating range. These results will have immediate impact on the design and development of TEGs and in the general design of devices based upon heterostructures that take advantage of gradients in the figure of merit.

A magnetoelectric coupled magneto-mechano-electric energy conversion mechanism allows the generation of high electrical power from ambient stray magnetic fields around infrastructures.