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The mid-wave infrared (MWIR), ranging from 2 to 5 micrometers, is of substantial interest for chemical sensing, imaging, and spectroscopy. Black phosphorus (bP)-based MWIR light emitters and detectors have been shown to outperform the state-of-the-art for commercial devices due to the low Auger recombination coefficient of bP. However, the scalability of these devices remains a challenge. Here, we report a bP ink formula that preserves the exceptional MWIR optoelectronic properties of bP to deposit centimeter-scale, uniform, and pinhole free films with a photoluminescence quantum yield higher than competing III-V and II-VI semiconductors with similar bandgaps at high excitation regime. As a proof of concept, we use bP ink as a phosphor on a red commercial light-emitting diode to demonstrate bright MWIR light emission. We also show that these films can be integrated into heterostructure device architectures with electron and hole selective contacts for direct-injected light emission and detection in MWIR.

The development of stimuli‐responsive liquid metal hybrids (SrLMHs) is of great interest, owing to their ability to induce responsivity and innovative properties to liquid metal (LM) when hybridized. Various stimuli‐responsivities yield new realms for SrLMHs in the fields of human‐interactive electronics (HIEs). This review provides an overview on the development of SrLMHs for HIEs. First, discussion is on SrLMH systems regarding their configuration, the materials utilized for the establishment of new hybrid materials, various stimuli‐responsive systems, their operation mechanisms, and applications. Followed by the characterization and summary of SrLMHs, details on how SrLMHs are incorporated for HIEs, and their progression is reviewed, from a single mechanical stimulus sensing capability to multi‐modal functionality. Finally, the review concludes on the overall progress of SrLMH‐based HIEs, their advancement direction, and the challenges that still remain. [ABSTRACT FROM AUTHOR]

2D MoS2 has gained attention for the post‐silicon material owing to its atomically thin nature and dangling bond‐free surface. The bi‐layer MoS2 is considered a promising material for electronic devices due to its better electrical properties than monolayer MoS2. However, the uniform growth of bi‐layer MoS2 is still challenging. Herein, the uniform growth of bi‐layer MoS2 is demonstrated using gas‐phase alkali metal‐assisted metal–organic chemical vapor deposition (GAA‐MOCVD). Thanks to enhanced metal reactant diffusion length in GAA‐MOCVD, the uniform growth of bi‐layer MoS2 film is achieved even at fast nucleation kinetics for a shorter growth time compared to previously reported MOCVD. The bi‐layer MoS2 field‐effect transistors (FETs) show superior electrical properties such as sheet conductance and electron mobility than monolayer MoS2 FETs. The electron mobility of bi‐layer MoS2 FETs with bismuth contacts reaches a maximum of 92.35 cm2 V−1 s−1. Using the partially grown epitaxial bi‐layer (PGEB) MoS2, it is demonstrated that a photodetector showed a near‐infrared photoresponse with a low dark current that is advantageous for both monolayer and bi‐layer applications. The potential expansion of the growth technique to layer‐by‐layer growth can result in boosted performance across a wide spectrum of electronic and optoelectronic devices employing MoS2. [ABSTRACT FROM AUTHOR]

Despite the remarkable progress in the development of sweat sensors, self‐powered sweat‐responsive sensing displays that detect sweat in electric signals with simultaneous and direct visualization of the sweat is rarely demonstrated. Here, a self‐powered sweat‐responsive structural color (SC) display enabled by ionomer‐doped block copolymer (BCP) photonic crystals (PCs) is presented. The sweat‐responsive BCP PC is developed by employing a cross‐linking single‐mobile ionomer (SMI) with mobile anions anchored to immobile polycations to a 1‐D BCP PC. The hydrophobic SMI‐doped BCP PC is mechanically robust as well as water and temperature‐resistive, exhibiting ionomer concentration‐dependent full visible SCs. Moreover, the mobile anions periodically confined in the SMI‐doped BCP PC harvest triboelectric energy, giving rise to a high‐power density of ≈0.774 Mw cm−2. Cation‐sensitive SC variation is observed in the SMI‐doped BCP PC, allowing the visualization of sweat containing various cations. A skin‐patchable self‐powered sweat‐responsive display is demonstrated in which kirigami‐patterned SMI‐doped BCP PC incorporated in the display can withstand up to 50% strain during exercise. Sweat from the exercise is visualized via SC display and measured using both ionic resistance changes and triboelectric signals. In addition, the integration of sweat sensing membrane into SMI‐doped BCP PC enables the quantification of sweat. [ABSTRACT FROM AUTHOR]

Displays are an effective way for humans to recognize information instantly and intuitively without linguistic barriers. Electrical sensors detect diverse human and environmental changes through variations in electrical signals; these data are delivered to a display connected to a sensor via a microprocessor, facilitating human/machine interface technologies. The development of an innovative one-integrated platform with optimized architectures, where a sensor and a display are converged, is essential for achieving efficient and rapid information management with low power consumption. These integrated stimuli-adaptive and human-interactive sensing displays (HISDs) electrically detect external stimuli and display an optical visualization simultaneously. Among numerous materials suitable for stimuli-adaptive displays and HISDs, self-assembled photonic crystals (PCs) of block copolymers (BCPs) are promising because of their structural colors (SCs) resulting from constructive interference of incident light. This review provides a comprehensive overview of recent developments in stimuli-adaptive SC displays using self-assembled BCP PCs. The responses of BCP SC displays, operating in liquid cells and solid-type films, to various external stimuli are described. Furthermore, emerging HISDs based on BCP PCs are discussed wherein external stimuli are electrically detected and simultaneous visualization of stimuli-adaptive SCs occurs. A perspective on the development of next-generation stimuli-adaptive BCP SC displays and HISDs is also provided. [ABSTRACT FROM AUTHOR]

For changing environmental circumstances, interactive structural color (SC) observation is a promising strategy to store and express external information. SCs based on self-assembled block copolymer (BCP) photonic crystals have been a research focus due to their facile and diverse nanostructures relying on the volume ratio of blocks. Their unique nano-architectonics can reflect incident light due to constructive interference of the two different dielectric constituents. Their excellent ability to change nano-architectonics in response to external stimuli (i.e. humidity, temperature, pH, and mechanical force) allows for a programmable and stimuli-interactive BCP SC display. In this review, recent advances in programmable and stimuli-interactive SC displays with the 1-dimensional self-assembled BCP nano-architectonics are comprehensively discussed. First, this review focuses on the development of programmable BCP SCs that can store various information. Second, stimuli-interactive BCP SCs capable of responding reversibly to external stimuli are also addressed. Particularly, reversible BCP SC changes are suitable for rewritable displays and emerging human-interactive BCP SC displays that detect various human information through changes in electric signals with the simultaneous alteration of the BCP SCs. Based on previously reported literature, the current challenges in this research field are further discussed, and the perspective for future development is presented in terms of material, nano-architectonics, and process. [ABSTRACT FROM AUTHOR]