Large-Area Black Phosphorus/PtSe2 Schottky Junction for High Operating Temperature Broadband Photodetectors.

High operating temperature (HOT) broadband photodetectors are urgently necessary for extreme condition applications in infrared-guided missiles, infrared night vision, fire safety imaging, and space exploration sensing. However, conventional photodetectors show dramatic carrier mobility decreases and carrier losses with low photoresponsivity at HOT due to the increased carrier scattering in channels at high temperatures. Herein, the HOT broadband photodetectors from room temperature to 470 K are developed for the first time by large-area black phosphorus (BP)/PtSe2 films device arrays via a depletion-enhanced photocarrier dynamics strategy. Attributed to the 2D Schottky junction at BP/PtSe2 interface and resulting in full depleted working channels, the BP/PtSe2 photodetector arrays exhibit high tolerance to carrier mobility decrease during the increasing operating temperature in a wide wavelength range from 532 to 2200 nm. Thus, the photodetector shows a state-of-the-art operating temperature at 470 K with the photo-responsivity (R) and specific detectivity (D*) of 25 A W-1 and 6.4 × 1011 Jones under 1850 nm illumination, respectively. Moreover, BP/PtSe2 photodetector arrays show high-uniformity photo-response in a large area. This work provides new strategies for high-performance broadband photodetector arrays with HOT by Schottky junction of large-area BP/PtSe2 films.

Regulating the Sequence Structure of Conjugated Block Copolymers Enables Large-Area Single-Component Organic Solar Cells with High Efficiency and Stability.

Single-component organic solar cells (SCOSCs) based on conjugated block copolymers (CBCs) by covalently bonding a polymer donor and polymer acceptor become more and more appealing due to the formation of a favorable and stable morphology. Unfortunately, a deep understanding of the effect of the assembly behavior caused by the sequence structure of CBCs on the device performance is still missing. Herein, from the aspect of manipulating the sequence length and distribution regularity of CBCs, we synthesized a series of new CBCs, namely D18(20)-b-PYIT, D18(40)-b-PYIT and D18(60)-b-PYIT by two-pot polymerization, and D18(40)-b-PYIT(r) by traditional one-pot method. It is observed that precise manipulation of sequence length and distribution regularity of the polymer blocks fine-tunes the self-assembly of the CBCs, optimizes film morphology, improves optoelectronic properties, and reduces energy loss, leading to simultaneously improved efficiency and stability. Among these CBCs, the D18(40)-b-PYIT-based device achieves a high efficiency of 13.4 % with enhanced stability, which is an outstanding performance among SCOSCs. Importantly, the regular sequence distribution and suitable sequence length of the CBCs enable a facile film-forming process of the printed device. For the first time, the blade-coated large-area rigid/flexible SCOSCs are fabricated, delivering an impressive efficiency of 11.62 %/10.73 %, much higher than their corresponding binary devices.

Green Solvent Ethanol-Based Inks for Industrially Applicable Deposition of High-Quality Perovskite Films for Optoelectronic Device Applications.

Incontrovertibly there is an increasing demand for the development of benign inks suitable for fabrication of high-performing perovskite-based thin film functional layers. Nevertheless, most reported perovskite precursors rely on the use of highly toxic solvents such as acetonitrile, 2-methoxyethanol, dimethylformamide, and many others. Hence, there is a strong imperative for the development of novel and greener inks, which will facilitate smoother commercialization of technologies based on functional perovskite films. Therefore, four perovskite precursors are studied, some of which consist of up to 90% ethanol. All inks are developed to fulfill the requirements of a high-throughput deposition compatible with roll-to-roll techniques at room temperature, assisted by an air knife for instant solvent removal. Two of the inks are particularly suitable for the fabrication of high-quality and densely packed multi-crystalline (CH3 NH3 )PbI3 layers, as confirmed by numerous nanoscale spectroscopic and material characterization techniques. Additionally, large-area photoluminescence (PL) imaging is demonstrated to improve the quality of the deposited perovskite films, with a route to enhance deposition uniformity when upscaling for manufacture. The genuine potential of the developed greener perovskite inks is demonstrated with the fabrication of solar cells with power conversion efficiencies above 19.5%.

Large-Area Flexible Carbon Nanofilms with Synergistically Enhanced Transmittance and Conductivity Prepared by Reorganizing Single-Walled Carbon Nanotube Networks.

Large-area flexible transparent conductive films (TCFs) are highly desired for future electronic devices. Nanocarbon TCFs are one of the most promising candidates, but some of their properties are mutually restricted. Here, a novel carbon nanotube network reorganization (CNNR) strategy, that is, the facet-driven CNNR (FD-CNNR) technique, is presented to overcome this intractable contradiction. The FD-CNNR technique introduces an interaction between single-walled carbon nanotube (SWNT) and Cu─-O. Based on the unique FD-CNNR mechanism, large-area flexible reorganized carbon nanofilms (RNC-TCFs) are designed and fabricated with A3-size and even meter-length, including reorganized SWNT (RSWNT) films and graphene and RSWNT (G-RSWNT) hybrid films. Synergistic improvement in strength, transmittance, and conductivity of flexible RNC-TCFs is achieved. The G-RSWNT TCF shows sheet resistance as low as 69 Ω sq-1 at 86% transmittance, FOM value of 35, and Young's modulus of ≈45 MPa. The high strength enables RNC-TCFs to be freestanding on water and easily transferred to any target substrate without contamination. A4-size flexible smart window is fabricated, which manifests controllable dimming and fog removal. The FD-CNNR technique can be extended to large-area or even large-scale fabrication of TCFs and can provide new insights into the design of TCFs and other functional films.

Wireless Flexible Magnetic Tactile Sensor with Super-Resolution in Large-Areas.

Tactile recognition is among the basic survival skills of human beings, and advances in tactile sensor technology have been adopted in various fields, bringing benefits such as outstanding performance in manipulating objects and general human-robot interactions. However, promoting enhanced perception of the existing tactile sensors is limited by their sensor array arrangement and wire-connected design. Here we present a wireless flexible magnetic tactile sensor (FMTS) consisting of a multidirection magnetized flexible film (perception module) and a contactless Hall sensor (signal receiving module). The flexible magnetic film is composed of NdFeB microparticles and soft silicone elastomer microparticles, and it transfers the unambiguous transduction of external force position and magnitude into magnetic signals. Benefiting from the specific magnetization arrangement and clustering algorithm, only one Hall sensor is needed in FMTS to perceive the magnitude and position of the contact spot simultaneously with super-resolution (2.1 mm average error) on a large area (3600 mm2), and the effective working distance is also greatly extended (∼30 mm), allowing for the full softness and adaptability to diverse conditions. We anticipate that this design will promote the development of soft tactile sensors and their integration into human-robot interaction and humanoid robot perception.

Natural Amino Acid Enables Scalable Fabrication of High-Performance Flexible Perovskite Solar Cells and Modules with Areas over 300 cm2.

Upscaling large-area formamidinium (FA)-based perovskite solar cells (PSCs) has been considered as one of the most promising routes for the commercial applications of this rising photovoltaics technology. Here, a natural amino acid, phenylalanine (Phe), is introduced to regulate the nucleation and crystal growth process of the large-scale coating of FA-based perovskite films. Better film coverage and larger grain sizes are observed after adding Phe. Moreover, it is found that Phe can effectively passivate defects within perovskite films and suppress the nonradiative recombination due to the strong interaction with under-coordinated Pb2+ ions in the perovskite films. Rigid PSCs based on the blade-coated perovskite films containing Phe obtain a champion efficiency of 21.95%. The corresponding unencapsulated devices also exhibit excellent ambient stability, retaining 95% of their initial efficiencies after storage in the glovebox at 20 °C for 1000 h. Further, the strategy is applied to fabricate flexible PSCs and modules on polyethylene terephthalate/indium doped tin oxide substrates via slot-die coating. Phe modified flexible devices achieve outstanding efficiencies of 20.21%, 12.1%, and 11.2% with aperture areas of 0.10, 185, and 333 cm2 , respectively. The strategy here has paved a promising way for the large-scale production of flexible PSCs.

Pixel Grafting: A Novel Skin Graft Expansion Technique.

Skin grafting is the transplantation of skin, a routinely performed procedure to cover the loss of skin. Skin is the largest organ of the body, which falls short of availability in extensive injuries, especially burns. In such a situation, pixel grafting, a novel expansion technique helps to cover a large area with less skin harvest. The objective of the study was to test fast, minimally invasive, easy to use minced split-thickness skin graft to cover large wounds and to reflect on the advantages of pixel graft. It is a pilot study of patients admitted with severe burns. We conclude that with this technique of pixel or minced grafting, large areas can be grafted with minimal donor-site requirement, and the techniques of preparation provide adequate size graft for pixel grafting.

Original and modified technique of tie-over dressing: Method and application in burn patients.

In burn patients, meshed split thickness skin grafts are commonly used on large and non-flat areas whom immobilization is difficult to achieve. The frequent mobilizations of burn patients can make the graft slip and prevent the revascularization and therefore the taking of the skin graft. In order to prevent this pitfall, we modified and adapted the tie-over dressing procedure. The giant running tie-over dressing enables large skin grafts to be applied to their wound bed and therefore helps revascularization. Some cautions are necessary in order to avoid any infection. This original and easy-to-perform procedure answers to the difficulties of large split-thickness skin grafts in burn patients.

ESTIMATION OF ATMOSPHERIC MIXING HEIGHTS OVER LARGE AREAS USING DATA FROM AIRPORT METEOROLOGICAL STATIONS.

For this study, ground and sounding meteorological data at 16 airports were used for estimating the atmospheric mixing heights in Hebei Province of China, including Beijing and Tanjing areas. Three methods were compared for this purpose, which are the dry adiabatic method, the conventional Nozaki model, and a modified Nozaki model. The feasibility of using airport meteorological data to determine mixing heights in large area was verified through the use of measured mixing heights and observed SO2 vertical profiles. The study not only estimated the mixing heights over large areas but also compared different early morning sounding temperature profiles to identify feasibility of using 2:00 a.m. sounding profiles to estimate mixing height by the dry adiabatic method. The paper also described the mixing heights over different areas such as mountain, sea boundary and plain areas. The results have considerable significance for air quality prediction and environmental management. A novel approach to estimation of atmospheric mixing heights over large area is introduced, requiring only the input of readily available airport meteorological data.

Ambient fabrication of large-area graphene films via a synchronous reduction and assembly strategy.

A synchronous reduction and assembly strategy is designed to fabricate large-area graphene films and patterns with tunable transmittance and conductivity. Through an oxidation-reduction reaction between the metal substrate and graphene oxide, graphene oxide is reduced to chemically converted graphene and is organized into highly ordered films in situ. This work will form the precedent for industrial-scale production of graphene materials for future applications in electronics and optoelectronics.