Random laser with intrinsically uncomplicated fabrication processes, high spectral radiance, angle-free emission, and conformal onto freeform surfaces is in principle ideal for a variety of applications, ranging from lighting to identification systems. In this work, a white random laser (White-RL) with high-purity and high-stability is designed, fabricated, and demonstrated via the cost-effective materials (e.g., organic laser dyes) and simple methods (e.g., all-solution process and self-assembled structures). Notably, the wavelength, linewidth, and intensity of White-RL are nearly isotropic, nevertheless hard to be achieved in any conventional laser systems. Dynamically fine-tuning colour over a broad visible range is also feasible by on-chip integration of three free-standing monochromatic laser films with selective pumping scheme and appropriate colour balance. With these schematics, White-RL shows great potential and high application values in high-brightness illumination, full-field imaging, full-colour displays, visible-colour communications, and medical biosensing.

An integrated random laser based on green materials with dissolubility and recyclability is created and demonstrated. The dissolvable and recyclable random laser (DRRL) can be dissolved in water, accompanying the decay of emission intensity and the increment in lasing threshold. Furthermore, the DRRL can be reused after the process of deionized treatment, exhibiting excellent reproducibility with several recycling processes.

With the rapid development of technology, electronic devices have become omnipresent in our daily life as they have brought much convenience in every aspect of human activity. Side-by-side, electronic waste (e-waste) has become a global environmental burden creating an ever-growing ecological problem. The transient device technology in which the devices can physically disappear completely in different environmental conditions has attracted widespread attention in recent years owing to its emerging application potential spanning from biomedical to military use. In this work, we demonstrated the first attempt for a dissolvable ecofriendly flexible photodetector using a hybrid of graphene and chlorophyll on a poly­(vinyl alcohol) substrate. The whole device can physically disappear in aqueous solutions in a time span of ∼30 min, while it shows a photoresponsivity of ∼200 A W–1 under ambient conditions. The high carrier mobility of graphene and strong absorption strength of a green photon harvesting layer, chlorophyll, result in the photocurrent gain of the device as high as 103 with subsecond response time under the illumination of red light. The newly designed photodetector shown here yields zero waste with a minimum impact on the environment, which is very useful for the development of the sustainability of our planet.

characteristics. Thus, tuning elements can be coordinated with the resonator. On the other hand, these methods do not work for the random laser system due to the absence of a periodic cavity. The simplicity and randomness set a hurdle for controlling random lasers. However, several approaches have been proposed to break through the bottlenecks. Here, we classify related studies into four main categories: wavelength manipulation, mode control, directional confinement, and threshold abatement. Wavelength manipulation is one of the most crucial parts of random lasers. There are two kinds of tuning designs, which are known as preprocess and postprocess, respectively. The tuning strategies of preprocess include modifying the absorption condition, [21,22] the size of scatterers, [23] and the geometry of photonic crystals. [24] Besides, external parameters such as optics, [25] electricity, [26] temperature, [27][28][29] and deformation, [30] can realize wavelength tunability after the fabrication of disordered nanostructures, so called postprocess. Further, people drive persistent endeavors to control the random lasing modes. Mode-locking and single-mode random lasers, the longstanding scientific goals, have been demonstrated by the pumping scheme, [31] Raman gain, [32] intentional defect sites, [33] and bioinspired photonic structure. [34] Modetransition can also be accomplished by altering the pumping condition, [35] modulating the concentration of gain media or scatterers, [36,37] and the mechanically induced reformation. [38] Although inherent angle-free emissions of random lasers are useful for some specific applications, a directional output is also highly desired. Several directional confinements have been introduced into random lasing systems such as low-dimensional cavities, [29,39] optical waveguides, [40,41] and customized pump profiles. [42] The strategies for lowering the lasing threshold have been extensively studied, e.g., optimization of the mean free path and particle size [43,44] or fine-tuning the concentration or refractive index between scattering and gain media. [45,46] In addition, fluorescence resonance energy transfer and surface plasmon resonance have also been highly addressed. [47][48][49] Here, a simple and straightforward design of magnetically controllable random lasers (MCRLs) is presented. Stilbene 420 laser dye, titanium dioxide nanoparticles (TiO 2 NPs), and ferrous ferric oxide nanoparticles (Fe 3 O 4 NPs) are chosen to compose the MCRLs. Stilbene 420 laser dye is selected from various laser dyes as the gain media because of its exceptional Toward practical applications of random lasers, controllability is a key factor. Here, magnetically controllable random lasers (MCRLs) are designed, fabricated, and demonstrated. Under a prescribed magnetic field, the MCRLs composed of stilbene 420 laser dye, TiO 2 nanoparticles, and Fe 3 O 4 nanoparticles possess magnetic controllability and switchability with good responsivity and durability. The applied magnetic field can be used to manipulate t...

In recent years, flexible magnetoelectronics has attracted a great attention for its intriguing functionalities and potential applications, such as healthcare, memory, soft robots, navigation, and touchless human-machine interaction systems. Here, we provide the first attempt to demonstrate a new type of magneto-piezoresistance device, which possesses an ultrahigh sensitivity with several orders of resistance change under an external magnetic field (100 mT). In our device, Fe-Ni alloy powders are embedded in the silver nanowire-coated micropyramid polydimethylsiloxane films. Our devices can not only serve as an on/off switch but also act as a sensor that can detect different magnetic fields because of its ultrahigh sensitivity, which is very useful for the application in analog signal communication. Moreover, our devices contain several key features, including large-area and easy fabrication processes, fast response time, low working voltage, low power consumption, excellent flexibility, and admirable compatibility onto a freeform surface, which are the critical criteria for the future development of touchless human-machine interaction systems. On the basis of all of these unique characteristics, we have demonstrated a nontouch piano keyboard, instantaneous magnetic field visualization, and autonomous power system, making our new devices be integrable with magnetic field and enable to be implemented into our daily life applications with unfamiliar human senses. Our approach therefore paves a useful route for the development of wearable electronics and intelligent systems.