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An unconventional organic solar cell structure based on hyperbolic metamaterials (HMMs) was designed, fabricated, and demonstrated with improved performance for the first time.

The clean production of hydrogen from water using sunlight has emerged as a sustainable alternative toward large-scale energy generation and storage. However, designing photoactive semiconductors that are suitable for both light harvesting and water splitting is a pivotal challenge. Atomically thin transition metal dichalcogenides (TMD) are considered as promising photocatalysts because of their wide range of available electronic properties and compositional variability. However, trade-offs between carrier transport efficiency, light absorption, and electrochemical reactivity have limited their prospects. We here combine two approaches that synergistically enhance the efficiency of photocarrier generation and electrocatalytic efficiency of two-dimensional (2D) TMDs. The arrangement of monolayer WS

Random lasers exhibit many exotic properties, including chaotic behavior, light localization, broad angular emission, and cost-effective fabrication, which enable them to attract both scientific and industrial interests. However, before the realization of their potential applications, several challenges still remain including the underlying mechanism and controllability due to their inherent multidirectional and chaotic fluctuations. Through more than two decades of collaborative efforts, the discovery of Anderson localization in random lasers provides a plausible route to resolve the difficulties, which enables one to tailor the number of lasing modes and stabilize the emission spectra. However, the related studies are rather rare and only restricted to limited wavelengths. In this study, based on enhanced Anderson localization assisted by surface plasmon resonance, spectrally stable deep-ultraviolet lasing action in AlGaN multiple quantum wells (MQWs) is demonstrated. Our work serves as firm evidence to demonstrate the underlying mechanism of stabilized deep-ultraviolet random laser action that multiple scattering of a light beam in a disordered medium can induce Anderson localization similar to electron behavior. This feature covers the whole spectral range, and it is a universal phenomenon of an electromagnetic wave. Notably, stabilized deep-ultraviolet random laser action has not been demonstrated in all previous studies, even though it has great academic interest and potential application in many areas from environmental protection to biomedical engineering.

Cancer is the leading cause of death in Taiwan, and the overall incidence rate has gradually increased. The four most common cancers in Taiwan are colorectal, lung, breast and liver cancers. With the rise in incidence, the clinical use and costs of all anticancer drugs have steadily increased. The costs of novel therapeutics, such as targeted therapies and immunotherapy were accounted almost two-third of all antineoplastic agents in Taiwan. Moving forward, it will be necessary to discuss the economic impacts to clinical use of new therapeutics, while continuing to monitor and improve the quality of cancer therapy. In this review, we describe the epidemiology, disease screening policies and medication treatment policies for colorectal, lung, breast and liver cancer. We focus on the recent developments in cancer therapeutics, discuss the use of biomarkers, and finally consider the costs and the recent advances of anticancer medications in Taiwan.

With the superiority of laser-level intensity, narrow spectral line width, and broad-angular emission, random lasers (RLs) have drawn considerable research interests for their potential to carry out a variety of applications. In this work, the applications associated with optical-encoded technologies, including security printing, military friend or foe identification (FFI), and anticounterfeiting of documents are highlighted, and the concept of a transient RL "smart ink" has been proposed. The proof-of-concept was demonstrated as invisible signatures, which encoded the messages through the spectral difference of spontaneous emission and RL under specified conditions. Next, the possibility of encoding the data with multibit signals was further confirmed by exploiting the threshold tunability of RLs. Moreover, the transient characteristic of this smart ink and its capability to be attached on freeform surfaces of different materials were also shown. With the advantages of a facile manufacturing process and multiple purposes, it is expected that this ink can soon be carried out in a variety of practical utilities.

Metal-organic frameworks (MOFs) are superior for multiple applications including drug delivery, sensing, and gas storage because of their tunable physiochemical properties and fascinating architectures. Optoelectronic application of MOFs is difficult because of their porous geometry and conductivity issues. Recently, a few optoelectronic devices have been fabricated by a suitable design of integrating MOFs with other materials. However, demonstration of laser action arising from MOFs as intrinsic gain media still remains challenging, even though some studies endeavor on encapsulating luminescence organic laser dyes into the porous skeleton of MOFs to achieve laser action. Unfortunately, the aggregation of such unstable laser dyes causes photoluminescence quenching and energy loss, which limits their practical application. In this research, unprecedently, we demonstrated ultralow-threshold (∼13 nJ/cm

Light emitting diodes (LEDs) are ubiquitous in our daily life nowadays. Among them, ultraviolet LEDs are unique because of their wide range of potential applications, spanning from biomedicine, env...

Multifunctional lanthanide-doped upconversion nanoparticles (UCNPs) have spread their wings in the fields of flexible optoelectronics and biomedical applications. One of the ongoing challenges lies in achieving UCNP-based nanocomposites, which enable a continuous-wave (CW) laser action at ultralow thresholds. Here, gold sandwich UCNP nanocomposites [gold (Au

To surmount the scalability limitations of the nano-electronics industry, the invention of resistance random access memory (RRAM) has drawn considerable attention in recent years for being a new-er...

Hyperbolic metamaterials (HMMs) have attracted significant attention due to the profound manipulation of the photonic density of states, resulting in the efficient optoelectronic devices with the enhanced light-matter interaction. HMMs are conventionally built on rigid large-size substrates with poor conformability and the absence of flexibility. Here, we demonstrate a grating collageable HMM (GCHMM), which is composed of eight alternating layers of Au and poly(methyl methacrylate) (PMMA) and PMMA grating nanostructure containing quantum dots (QDs). The QDs serve as a scattering gain medium performing a random laser action, and the grating nanostructure enhances the extraction of light from QDs. The GCHMM enhances laser action by 13 times, reduces lasing threshold by 46%, and increases differential quantum efficiency by 1.8 times as compared to a planar collageable HMM. In addition, the GCHMM can be retransferred multiple times to other substrates as well as provide sufficient protection in water and still retain an excellent performance. It also shows stable functionality even when transferred to a dental floss. The GCHMM, therefore, promises to become a versatile platform for foldable, adaptable, free-standing, and water-resistant optoelectronic device applications.

It has been demonstrated that the WS2 monolayer is an excellent template for AlN epitaxy at 400 °C low temperature. Low-temperature AlN thin films exhibit much superior crystalline quality than those grown directly on sapphire substrates. In addition to the small lattice mismatch between AlN and WS2 monolayer, we proposed a growth mechanism to explain the excellent van der Waal epitaxy by looking at the initial growth. This growth model reveals that transition metal dichalcogenides (TMDCs) are promising buffer layers for the deposition of III-nitrides but also suggests the novel combination of AlN and TMDCs in the research of future 2D field-effect transistors due to the extremely low leakage current of high-quality AlN films.

The development of optical memory with attractive features such as long-lasting, nonvolatile, high-speed, and low-energy consumption is vitally important in the information age. Owing to these adva...

Dual-functional devices that can simultaneously detect light and emit light have a tremendous appeal for multiple applications, including displays, sensors, defense, and high-speed optical communication. Despite the tremendous efforts of scientists, the progress of integration of a phototransistor, where the built-in electric field separates the photogenerated excitons, and a light-emitting diode, where the radiative recombination can be enhanced by band offset, into a single device remains a challenge. Combining the superior properties of perovskite quantum dots (PQDs) and graphene, here we report a light-emissive, ultrasensitive, ultrafast, and broadband vertical phototransistor that can simultaneously act as an efficient photodetector and light emitter within a single device. The estimated value of the external quantum efficiency of the vertical phototransistor is ∼1.2 × 10

Stretchable optoelectronic devices are the need of the hour when it comes to making present day technologies user-friendly. These devices when placed conformably on the human skin or any other arti...

Two-dimensional (2D) material nanocomposites have emerged as a material system for discovering new physical phenomena and developing novel devices. However, because of the low density of states of most two-dimensional materials such as graphene, the heterostructure of nanocomposites suffers from an enhanced depletion region, which can greatly reduce the efficiency of the charge carrier transfer and deteriorate the device performance. To circumvent this difficulty, here we propose an alternative approach by inserting a second 2D mediator with a heavy effective mass having a large density of states in-between the heterojunction of 2D nanocomposites. The mediator can effectively reduce the depletion region and form a type-II band alignment, which can speed up the dissociation of electron-hole pairs and enhance charge carrier transfer. To illustrate the principle, we demonstrate a novel stretchable photodetector based on the combination of graphene/ReS

Two-dimensional ternary materials are attracting widespread interest because of the additional degree of freedom available to tailor the material property for a specific application. An In1-xSnxSe phototransistor possessing tunable ultrahigh mobility by Sn-doping engineering is demonstrated in this study. A striking feature of In1-xSnxSe flakes is the reduction in the oxide phase compared to undoped InSe, which is validated by spectroscopic analyses. Moreover, first-principles density functional calculations performed for the In1-xSnxSe crystal system reveal the same effective mass when doped with Sn atoms. Hence, because of an increased lifetime owing to the enhanced crystal quality, the carriers in In1-xSnxSe have higher mobility than in InSe. The internally boosted electrical properties of In1-xSnxSe exhibit ultrahigh mobility of 2560 ± 240 cm2 V-1 s-1 by suppressing the interfacial traps with substrate modification and channel encapsulation. As a phototransistor, the ultrathin In1-xSnxSe flakes are highly sensitive with a detectivity of 1014 Jones. It possesses a large photoresponsivity and photogain (Vg = 40 V) as high as 3 × 105 A W-1 and 0.5 × 106, respectively. The obtained results outperform all previously reported performances of InSe-based devices. Thus, the doping-engineered In1-xSnxSe-layered semiconductor finds a potential application in optoelectronics and meets the demand for faster electronic technology.

Dear Editor, Primary mucosal melanoma is a rare subtype of melanoma that carries poor prognosis. Traditional treatment options of mucosal melanoma are surgery, radiation, and chemotherapy; but the overall survival remains low.1 Cytotoxic T‐lymphocyte associated protein 4 (CLTA‐4) and programmed cell death protein 1 (PD‐1), both inhibitory immune checkpoints commonly seen on activated T cells, have been found to be promising targets for treatment of advanced cancers.2 However, the efficacy and response to immunotherapy in mucosal melanoma remains unknown. Herein, we report a case involving a patient, who was a 70‐year‐old male and referred to Taipei Medical University Hospital with confirmed diagnosis of mucosa melanoma over hard plate of mouth. The patient was admitted and subjected to anti‐PD‐1 immunotherapy (pembrolizumab 200 mg every 3 weeks) (Figure 1A). Serial imaging of primary malignant melanoma of the hard palate showed that the tumor size gradually decreased after treatment with pembrolizumab, suggesting partial response/stable disease secondary to continuous immunotherapy (Figure 1B). However, after seventh cycle of treatment, magnetic resonance imaging (MRI) revealed enlarged previous known metastatic lesions and new tumor nodules in brain (Figure 1B). The patient received stereotactic radiation therapy before treatment cycle 14 (Figure 1A). Although the primary metastatic brain lesions were smaller and stationary after radiotherapy, the following brain MRI displayed several hyperdensity masses in the right frontal lobe with perifocal edema and mild mass effect (Figure 1B). Subsequently, patient suffered from infection and respiratory distress and died 2 months after 17th cycle of pembrolizumab therapy.

To explore the clinical efficacy of silver needle lumbar and sacral spine approach in treating gluteal muscle syndrome.Eighty-seven patients with gluteal muscle syndrome treated with silver needles in the Department of Rehabilitation Medicine of our hospital from September 2017 to September 2019 were selected. Except for symptoms of waist and hip pain and discomfort, all selected patients were examined by CT or MRI to confirm pathological imaging changes such as inflammatory exudation of the gluteal muscle. The 87 patients with gluteal muscle syndrome were divided into 2 groups according to the digital table method, and 42 patients in the lumbosacral approach group, including 19 males and 23 females, aged (50.70±12.45) years old, and disease duration of (1.63±1.27) years;45 cases in the buttock approach group, including 20 males and 25 females, aged (52.80±12.18) years old, with a course of disease of (1.78±1.22) years. The lumbosacral approach group was treated with spinal LAfter 4 weeks, the VAS score of the lumbosacral approach group was 1.26±0.70, and the buttock approach group was 1.18±0.74, which were significantly lower than those before treatment, but there was no statistical difference between the groups (In the treatment of gluteus medius syndrome with silver needle, lumbosacral approach and buttock approach can effectively relieve the pain. Compared with the improvement of soft tissue tenderness threshold and hip abductor muscle strength, the upper lumbosacral approach is more prominent, and the overall clinical effect is more significant.

Optical memories are vitally important for the future development of high speed and low cost information technologies. Current optical memory devices still suffer from difficulties such as scaling-down of size, short-life expectancy, and non-volatility without the control of a gate electrode. To resolve these obstacles, a robust photoelectronic memory device is designed and demonstrated based on the integration of amorphous InGaZnO (a-IGZO), GNSs, and nitride multiple-quantum-wells light-emitting diode (MQWs LED). Utilizing the inherent nature of the band alignment between a-IGZO and graphene nanosheets (GNSs), electrons can transfer from a-IGZO to GNSs causing a persistent photoconductivity (PPC). With the long-lasting lifetime of PPC, the signal can be written optically and the encoded signal can be read both electrically and optically. The read and write processes reveal little current degradation for more than 10,000 sec, even repeated for more than hundred times. The device can convert invisible information to visible signal, and the encoded information can be simply erased under a reversed bias without a gate electrode. In addition, the memory device possesses a simple vertically stacked structure for 3D integration, and it is compatible with established technologies.

The emergence of self-healing devices in recent years has drawn a great amount of attention in both academics and industry. Self-healed devices can autonomically restore a rupture as unexpected destruction occurs, which can efficiently prolong the life span of the devices; hence, they have an enhanced durability and decreased replacement cost. As a result, integration of wearable devices with self-healed electronics has become an indispensable issue in smart wearable devices. In this study, we present the first self-powered, self-healed, and wearable ultraviolet (UV) photodetector based on the integration of agarose/poly(vinyl alcohol) (PVA) double network (DN) hydrogels, which have the advantages of good mechanical strength, self-healing ability, and tolerability of multiple types of damage. With the integration of a DN hydrogel substrate, the photodetector enables 90% of the initial efficiency to be restored after five healing cycles, and each rapid healing time is suppressed to only 10 s. The proposed device has several merits, including having an all spray coating, self-sustainability, biocompatibility, good sensitivity, mechanical flexibility, and an outstanding healing ability, which are all essential to build smart electronic systems. The unprecedented self-healed photodetector expands the future scope of electronic skin design, and it also offers a new platform for the development of next-generation wearable electronics.

Printed random lasers with great versatility, compatibility, and universality can be well adopted by most of the commercial inkjet printers or 3D printers in the mainstream market, promising high application values from lab to fab.

Towards the sustainable development, optoelectronic devices with biodegradability and biocompatibility have been a desirable but challenging issue for years. In this study, an all-biomaterial random laser device based on all-marine elements has been demonstrated. Chlorophyll and blue coral skeletons serve as gain medium and scattering centers, respectively. The chlorophyll is derived from marine diatoms, which are ubiquitous in the ocean and set up an abundant source for the device. On the other hand, the coral skeletons with intrinsic nanorod structures can provide a strong optical confinement and feedback for laser action. The proposed design signifies the novel application of marine materials and represents a significant step for the development of bio-inspired photonics modules.

Visible blind near-infrared (NIR) photodetection is essential when it comes to weapons used by military personnel, narrow band detectors used in space navigation systems, medicine, and research studies. The technological field of filterless visible blind, NIR omnidirectional photodetection and wearability is at a preliminary stage. Here, we present a filterless and lightweight design for a visible blind and wearable NIR photodetector capable of harvesting light omnidirectionally. The filterless NIR photodetector comprises the integration of distinct features of lanthanide-doped upconversion nanoparticles (UCNPs), graphene, and micropyramidal poly(dimethylsiloxane) (PDMS) film. The lanthanide-doped UCNPs are designed such that the maximum narrow band detection of NIR is easily accomplished by the photodetector even in the presence of visible light sources. Especially, the 4fn electronic configuration of lanthanide dopant ions provides for a multilevel hierarchical energy system that provides for longer lif...

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, chl...

Organic–inorganic hybrid two-dimensional (2D) perovskites have recently attracted great attention in optical and optoelectronic applications due to their inherent natural quantum-well structure. We report the growth of high-quality millimeter-sized single crystals belonging to homologous two-dimensional (2D) hybrid organic–inorganic Ruddelsden–Popper perovskites (RPPs) of (BA)2(MA)n−1PbnI3n+1 (n = 1, 2, and 3) by a slow evaporation at a constant-temperature (SECT) solution-growth strategy. The as-grown 2D hybrid perovskite single crystals exhibit excellent crystallinity, phase purity, and spectral uniformity. Low-threshold lasing behaviors with different emission wavelengths at room temperature have been observed from the homologous 2D hybrid RPP single crystals. Our result demonstrates that solution-growth homologous organic–inorganic hybrid 2D perovskite single crystals open up a new window as a promising candidate for optical gain media.

Numerous investigations of photon upconversion in lanthanide-doped upconversion nanoparticles (UCNPs) have led to its application in the fields of bioimaging, biodetection, cancer therapy, displays, and energy conversion. Herein, we demonstrate a new approach toward lanthanide-doped UCNPs and a graphene hybrid planar and rippled structure photodetector. The multi-energy sublevels from the 4fn electronic configuration of lanthanides results in longer excited state lifetime for photogenerated charge carriers. This opens up a new regime for ultra-high-sensitivity and broadband photodetection. Under 808 nm infrared light illumination, the planar hybrid photodetector shows a photoresponsivity of 190 AW–1, which is higher than the currently reported responsivities of the same class of devices. Also, the rippled graphene and UCNPs hybrid photodetector on a poly(dimethylsiloxane) substrate exhibits an excellent stretchability, wearability, and durability with high photoresponsivity. This design makes a significan...

Flexible optoelectronic devices facilitated by the piezotronic effect have important applications in the near future in many different fields ranging from solid-state lighting to biomedicine. Two-dimensional materials possessing extraordinary mechanical strength and semiconducting properties are essential for realizing nanopiezotronics and piezo-phototronics. Here, we report the first demonstration of piezo-phototronic properties in In1−xSnxSe flexible devices by applying systematic mechanical strain under photoexcitation. Interestingly, we discover that the dark current and photocurrent are increased by five times under a bending strain of 2.7% with a maximum photoresponsivity of 1037 AW−1. In addition, the device can act as a strain sensor with a strain sensitivity up to 206. Based on these values, the device outperforms the same class of devices in two-dimensional materials. The underlying mechanism responsible for the discovered behavior can be interpreted in terms of piezoelectric potential gating, allowing the device to perform like a phototransistor. The strain-induced gate voltage assists in the efficient separation of photogenerated charge carriers and enhances the mobility of In1−xSnxSe, resulting in good performance on a freeform surface. Thus, our multifunctional device is useful for the development of a variety of advanced applications and will help meet the demand of emerging technologies.

Carbon dots have emerged as popular materials in various research fields, including biological and photovoltaic areas, while significant reports are lacking related to their applications in laser devices, which play a significant role in our daily life. In this work, we demonstrate the first controllable random laser assisted by the surface plasmon effect of carbon dots. Briefly, carbon dots derived from candle soot are randomly deposited on the surface of gallium nitride (GaN) nanorods to enhance the ultraviolet fluorescence of GaN and generate plasmonically enhanced random laser action with coherent feedback. Furthermore, potentially useful functionalities of tunable lasing threshold and controllable optical modes are achieved by adjusting the numbers of carbon dots, enabling applications in optical communication and identification technologies. In addition to providing an efficient alternative for plasmonically enhanced random laser devices with simple fabrication and low cost, our work also paves a us...

Hyperbolic metamaterials have emerged as novel materials with exciting functionalities, especially for optoelectronic devices. Here, we provide the first attempt to integrate hyperbolic metamaterials with light emitting nanostructures, which enables to strongly enhance random laser action with reduced lasing threshold. Interestingly, the differential quantum efficiency can be enhanced by more than four times. The underlying mechanism can be interpreted well based on the fact that the high-k modes excited by hyperbolic metamaterials can greatly increase the possibility of forming close loops decreasing the energy consumption for the propagation of scattered photons in the matrix. In addition, out-coupled propagation of the high-k modes reaches to the far-field without being trapped inside the metamaterials due to the coupling with the random distribution of light emitting nanoparticles also plays an important role. Electromagnetic simulations derived from the finite-difference time-domain (FDTD) method are...

Integrating different dimentional materials on vertically stacked p-n hetero-junctions have facinated a considerable scrunity and can open up excellent feasibility with various functionalities in opto-electronic devices. Here, we demonstrate that vertically stacked p-GaN/SiO2/n-MoS2/Graphene heterostructures enable to exhibit prominent dual opto-electronic characteristics, including efficient photo-detection and light emission, which represents the emergence of a new class of devices. The photoresponsivity was found to achieve as high as ~10.4 AW−1 and the detectivity and external quantum efficiency were estimated to be 1.1 × 1010 Jones and ~30%, respectively. These values are superier than most reported hererojunction devices. In addition, this device exhibits as a self-powered photodetector, showing a high responsivity and fast response speed. Moreover, the device demonstrates the light emission with low turn-on voltage (~1.0 V) which can be realized by electron injection from graphene electrode and holes from GaN film into monolayer MoS2 layer. These results indicate that with a suitable choice of band alignment, the vertical stacking of materials with different dimentionalities could be significant potential for integration of highly efficient heterostructures and open up feasible pathways towards integrated nanoscale multi-functional optoelectronic devices for a variety of applications.

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.

Total internal reflection is one of the most important phenomena when a propagated wave strikes a medium boundary, which possesses a wide range of applications spanning from optical communication to a fluorescence microscope. It has also been widely used to demonstrate conventional laser actions with resonant cavities. Recently, cavity-free stimulated emission of radiation has attracted great attention in disordered media because of several exciting physical phenomena, ranging from Anderson localization of light to speckle-free imaging. However, unlike conventional laser systems, the total internal reflection has never been implemented in the study of laser actions derived from randomly distributed media. Herein, we demonstrate an ultra-low threshold cavity-free laser system using air bubbles as scattering centers in which the total internal reflection from the surface of air bubbles can greatly reduce the leakage of the scattered beam energy and then enhance light amplification within a coherent closed loop. Our approach provides an excellent alternative for the manipulation of optical energy flow to achieve ultra-low threshold cavity-free laser systems, which should be very useful for the development of high performance optoelectronic devices.

A previously unexplored paradigm enables electrically driven quantum dot random lasers., The many distinct advantages of random lasers focused efforts on developing a breakthrough from optical pumping to electrical pumping. However, progress in these is limited due to high optical loss and low gain. In this work, we demonstrate an electrically pumped quantum dot (QD) random laser with visible emission based on a previously unexplored paradigm named coherent Förster resonance energy transfer (CFRET). In the CFRET process, when a coherent photonic mode is formed because of multiple scattering of the emitted light traveling in mixed donor and acceptor QDs, the donor QDs not only serve as scattering centers but are also enable coherent energy transfer to acceptor QDs. Therefore, the laser action can be easily achieved, and the lasing threshold is greatly reduced. Our approach of electrically pumped QD-based random lasers represents a substantial step toward a full-spectrum random laser for practical applications.

Two-dimensional ternary materials are attracting widespread interest because of the additional degree of freedom available to tailor the material property for a specific application. An In

Light-based information processing has the potential to increase speed, security, and scalability of electronic devices if issues in the device complexity could be resolved. We here demonstrate an integrated nanoelectronic device that can combine, store, and manipulate optical and electronic information. Employing a mechanically flexible and multilayered structure, a device is realized that shows memristive behavior. Illumination is shown to control the device operation in several unique ways. First, the device produces photocurrent that allows us to read out the device state in a self-powered manner. More importantly, a varying light intensity modulates the switching transition in a proportional manner that is akin to a neuron with variable plasticity and which can be taught and queried using either light or electrical inputs. This behavior enables a multilevel light-controlled logic and teaching schemes that can be applied to light-based communication devices and provides a route toward ubiquitous and low-cost sensors for future internet of things applications.

2D ternary semiconductor single crystals, an emerging class of new materials, have attracted significant interest recently owing to their great potential for academic interest and practical application. In addition to other types of metal dichalcogenides, 2D tin dichalcogenides are also important layered compounds with similar capabilities. Yet, multi-elemental single crystals enable to assist multiple degrees of freedom for dominant physical properties via ratio alteration. This study reports the growth of single crystals Se-doped SnS2 or SnSSe alloys, and demonstrates their capability for the fabrication of phototransistors with high performance. Based on exfoliation from bulk high quality single crystals, this study establishes the characteristics of few-layered SnSSe in structural, optical, and electrical properties. Moreover, few-layered SnSSe phototransistors are fabricated on both rigid (SiO2/Si) and versatile polyethylene terephthalate substrates and their optoelectronic properties are examined. SnSSe as a phototransistor is demonstrated to exhibit a high photoresponsivity of about 6000 A W−1 with ultra-high photogain (η) ≈8.8 × 105, fast response time ≈9 ms, and specific detectivity (D*) ≈8.2 × 1012 J. These unique features are much higher than those of recently published phototransistors configured with other few-layered 2D single crystals, making ultrathin SnSSe a highly qualified candidate for next-generation optoelectronic applications.

Nanoscrolls are a class of nanostructures where atomic layers of 2D materials are stacked consecutively in a coaxial manner to form a 1D spiral topography. Self-assembly of chemical vapor deposition grown 2D WS2 monolayer into quasi-1D van der Waals scroll structure instigates a plethora of unique physiochemical properties significantly different from its 2D counterparts. The physical properties of such nanoscrolls can be greatly manipulated upon hybridizing them with high-quantum-yield colloidal quantum dots, forming 0D/2D structures. The efficient dissociation of excitons at the heterojunctions of QD/2D hybridized nanoscrolls exhibits a 3000-fold increased photosensitivity compared to the pristine 2D-material-based nanoscroll. The synergistic effects of confined geometry and efficient QD scatterers produce a nanocavity with multiple feedback loops, resulting in coherent lasing action with an unprecedentedly low lasing threshold. Predominant localization of the excitons along the circumference of this helical scroll results in a 12-fold brighter emission for the parallel-polarized transition compared to the perpendicular one, as confirmed by finite-difference time-domain simulation. The versatility of hybridized nanoscrolls and their unique properties opens up a powerful route for not-yet-realized devices toward practical applications.

Production of multicolor or multiple wavelength lasers over the full visible-color spectrum from a single chip device has widespread applications, such as superbright solid-state lighting, color laser displays, light-based version of Wi-Fi (Li-Fi), and bioimaging, etc. However, designing such lasing devices remains a challenging issue owing to the material requirements for producing multicolor emissions and sophisticated design for producing laser action. Here we demonstrate a simple design and highly efficient single segment white random laser based on solution-processed NaYF4:Yb/Er/Tm@NaYF4:Eu core–shell nanoparticles assisted by Au/MoO3 multilayer hyperbolic meta-materials. The multicolor lasing emitted from core–shell nanoparticles covering the red, green, and blue, simultaneously, can be greatly enhanced by the high photonic density of states with a suitable design of hyperbolic meta-materials, which enables decreasing the energy consumption of photon propagation. As a result, the energy upconversion...

Tuberculosis (TB) remains the leading cause of morbidity and mortality from infectious disease in developing countries. The sputum smear microscopy remains the primary diagnostic laboratory test. However, microscopic examination is always time-consuming and tedious. Therefore, an effective computer-aided image identification system is needed to provide timely assistance in diagnosis. The current identification system usually suffers from complex color variations of the images, resulting in plentiful of false object detection. To overcome the dilemma, we propose a two-stage Mycobacterium tuberculosis identification system, consisting of candidate detection and classification using convolution neural networks (CNNs). The refined Faster region-based CNN was used to distinguish candidates of M. tuberculosis and the actual ones were classified by utilizing CNN-based classifier. We first compared three different CNNs, including ensemble CNN, single-member CNN, and deep CNN. The experimental results showed that both ensemble and deep CNNs were on par with similar identification performance when analyzing more than 19,000 images. A much better recall value was achieved by using our proposed system in comparison with conventional pixel-based support vector machine method for M. tuberculosis bacilli detection.

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.

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.

Towards the sustainable development, optoelectronic devices with biodegradability and biocompatibility have been a desirable but challenging issue for years. In this study, an all­biomaterial random laser device based on all-marine elements has been demonstrated. The chlorophyll is derived from marine diatoms, which are ubiquitous in the ocean and set up an abundant source for the device. On the other hand, the coral skeletons with intrinsic nanorod structures can provide a strong optical confinement and feedback for laser action. The proposed design signifies the novel application of marine materials and represents a significant step for the development of bio-inspired photonics modules.

A highly sensitive glucose biosensor based on vertically stacked van der Waals graphene/ZnO/p-Si heterojunctions is demonstrated. Its sensing mechanism makes use of the large variation in the Fermi energy of graphene upon direct electron transfer of glucose oxidase at the presence of glucose molecules, with a film of ZnO acting as a sieve layer to block the carriers from transferring into the underlying semiconductor layer, resulting in a superb detection sensitivity.