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Organic photodetectors (OPDs) have drawn extensive research efforts due to their tailorable spectral response, ease of processing, compatibility with flexible devices and cooling-free ...operations. In this review, we outline the promising strategies for constructing high-performance and highly stable photodiodes-based OPDs from the perspectives of molecular engineering, morphology control, and device structure design. Firstly, the impact of molecular design and morphology control on OPD performance is clearly underlined and the molecular design rules and quantitative analysis methods are presented for high-performance OPDs. Subsequently, some striking device designs for multifunctional applications are discussed to elucidate the corresponding mechanism for various responses. What follows are the research efforts of boosting OPD stability for commercial applications. This review not only presents the detailed discussion on various OPD strategies aiming at simultaneously enhancing performance and stability but also provides some insights for the remaining challenges to make further breakthrough of OPDs.
Recently, the use of a new family of electroluminescent copper(I) complexes—i.e., the archetypal Cu(IPr)(3‐Medpa)PF6 complex; IPr: 1,3‐bis‐(2,6‐di‐iso‐propylphenyl)imidazole‐2‐ylidene; 3‐Medpa: ...2,2′‐bis‐(3‐methylpyridyl)amine—has led to blue light‐emitting electrochemical cells (LECs) featuring luminances of 20 cd m−2, stabilities of 4 mJ, and efficiencies of 0.17 cd A−1. Herein, this study rationalizes how to enhance these figures‐of‐merit optimizing both device fabrication and design. On one hand, a comprehensive spectroscopic and electrochemical study reveals the degradation of this novel emitter in common solvents used for LEC fabrication, as well as the impact on the photoluminescence features of thin‐films. On the other hand, spectro‐electrochemical and electrochemical impedance spectroscopy assays suggest that the device performance is strongly limited by the irreversible formation of oxidized species that mainly act as carrier trappers and luminance quenchers. Based on all of the aforementioned, device optimization was realized using ionic additives and a hole transporter either as a host–guest or as a multilayered architecture approach to decouple hole/electron injection. The latter significantly enhances the LEC performance, reaching luminances of 160 cd m−2, stabilities of 32.7 mJ, and efficiencies of 1.2 cd A−1. Overall, this work highlights the need of optimizing both device fabrication and design toward highly efficient and stable LECs based on cationic copper(I) complexes.
New concepts about device fabrication and design toward efficient and stable blue light‐emitting electrochemical cells based on copper(I) complexes are provided. Spectro‐electrochemical and electrochemical impedance spectroscopy assays reveal the degradation mechanism upon device fabrication and the effect of the irreversible formation of oxidized species that act as carrier trappers and luminance quenchers under device operation conditions.
To keep pace with the increasing pursuit of portable and wearable electronics, it is urgent to develop advanced flexible power supplies. In this context, Zn‐ion batteries (ZIBs) have garnered ...increasing attention as favorable energy storage devices for flexible electronics, owing to the high capacity, low cost, abundant resources, high safety, and eco‐friendliness. Extensive efforts have been devoted to developing flexible ZIBs in the last few years. This work summarizes the recent achievements in the design, fabrication, and characterization of flexible ZIBs. Representative structures, such as sandwich and cable type, are particularly highlighted. Special emphasis is put on the novel design of electrolyte and electrode, which aims to endow reliable flexibility to the fabricated ZIBs. Moreover, current challenges and future opportunities for the development of high‐performance flexible ZIBs are also outlined.
The recent development of electrode materials, gel electrolytes, and device configurations for flexible zinc‐ion batteries (ZIBs) is reviewed. Recent progresses in flexible ZIBs are discussed by briefly categorizing into Zn–Mn based, Zn–V based, Zn–Prussian blue analog based, and the other ZIBs. The current challenges and future opportunities for the development of flexible ZIBs are also discussed.
Histotripsy is a non-invasive, non-ionizing, and non-thermal focused ultrasound ablation method that is currently being developed for the treatment of liver cancer. Promisingly, histotripsy has been ...shown for ablating primary (hepatocellular carcinoma, HCC) and metastatic (colorectal liver metastasis, CLM) liver tumors in preclinical and early clinical studies. The feasibility of treating cholangiocarcinoma (CC), a less common primary liver tumor that arises from the bile ducts, has not been explored previously. Given that prior work has established that histotripsy susceptibility is based on tissue mechanical properties, there is a need to explore histotripsy as a treatment for CC due to their dense fibrotic stromal components. In this work, we first investigated the feasibility of histotripsy for ablating CC tumors in vivo in a patient-derived xenograft mouse model. The results showed that histotripsy could generate CC tumor ablation using a 1 MHz small animal histotripsy system with treatment doses of 250, 500, and 1000 pulses/point. A second set of experiments compared the histotripsy doses required to ablate CC tumors to HCC and CLM tumors ex vivo. For this, human tumor samples were harvested after surgery and treated ex vivo with a 700 kHz clinical histotripsy transducer. Results demonstrated significantly higher treatment doses were required to ablate CC and CLM tumors compared to HCC, with the highest treatment dose required for CC tumors. Overall, the results of this study suggest that histotripsy has the potential to be used for the ablation of CC tumors while also highlighting the need for tumor-specific treatment strategies.
Reducing the cost of energy of wave energy converters is key for the advancement of the technology. The costs associated with the device structure show the highest potential to achieve this ...reduction. For this reason, many hull geometry optimisation studies have been performed over the last 20 years, with the aim of finding improved hull shapes, that maximise the power generation and minimise the costs. These studies have been performed for different types of devices, applying a number of optimisation algorithms and representing power generation and costs with various strategies. The definition of the optimisation problem and the use of the most suitable strategies is key for a successful optimisation process, which will provide meaningful results and support device design at early development stages. This paper reviews all these different approaches, with a view to distilling the main findings and best practices; it then formulates recommendations based on these. The work is intended to serve as reference for any technology developer wishing to perform wave energy converter optimisation and for any funding body wanting to assess different device designs.
•Wave energy converter hull optimisation results improve if using adaptable geometry definitions such as B-spline surfaces.•The optimisation algorithm and set-up should be selected to improve computational time without reducing model accuracy.•Annual energy production and surface area based objective functions result in good trade-offs of performance and costs.
The progressive development of flexible transparent portable electronic devices is in urgent need of matching power sources. Flexible transparent supercapacitors (FTSCs) are the core resources due to ...their high optical transmittance, endurable mechanical flexibility, excellent electrochemical performance, and facilely accessible device configuration. This review organizes the rational design of nanostructured electrode materials toward FTSCs. First, the structure, mechanism, and property of FTSCs are introduced. Then, the design principles of diverse electrode materials are discussed to achieve flexible transparent conductive electrodes (FTCEs) with different figure of merits (both electrical FoMe and capacitive FoMc), mechanical strength, and environmental stability. Following the achievements in multifunctional FTSCs focusing on film‐supercapacitors, micro‐supercapacitors, electrochromic supercapacitors, photo‐supercapacitors, and battery‐like supercapacitors are also highlighted. Finally, the current challenges and future perspectives on viable materials in the construction of FTSCs to power portable electronics are outlined.
The development of flexible transparent supercapacitors (FTSCs) as power sources is of significance to the next generation of flexible transparent smart electronics. This review first highlights the structure, mechanism, and property of FTSCs, and then summarizes the design principles of each representative electrode material and device configuration. The insights in the prospective exploration directions of electrode materials and FTSCs are discussed.
Ultra-fast laser ultrasonic imaging method for online inspection of metal additive manufacturingIn this paper, an ultra-fast laser ultrasonic imaging method is proposed to provide an efficient online ...monitoring of additive manufacturing (AM) processing. The innovations of the proposed ultrafast imaging method in this research mainly include two parts. Firstly, multi-circle combined scanning strategy and defect location algorithm is constructed to improve the detection efficiency. Secondly, a surface wave focusing algorithm (SWFA) is established to solve the problem of low SNR induced by rough surface signals.The highlights of the paper are:•The minimum detectable defect reaches 0.1 mm and the quantitative error could low down to 6.46% when the defect size is larger than 0.2 mm.•Compared with the C-scan imaging method, the method proposed in this paper can improve the scanning efficiency of single-layer inspection by more than 300%, which is meaningful to improve the efficiency of metal additive manufacturing.
In this paper, an ultra-fast laser ultrasonic imaging method is proposed to provide an efficient online monitoring of additive manufacturing (AM) processing. The innovations of the proposed ultrafast imaging method in this research mainly include two parts. Firstly, multi-circle combined scanning strategy and defect location algorithm is constructed to improve the detection efficiency. Secondly, a surface wave focusing algorithm (SWFA) is established to solve the problem of low SNR induced by rough surface signals. The AM samples containing four types of surface and inner defects are designed and manufactured to verify the detectability and quantitative accuracy of the proposed method. Systematically comparisons between our proposed method with the traditional laser ultrasonic imaging are also discussed. The result indicated that the proposed ultra-fast imaging method is efficient for detecting the surface and sub-surface defects in the condition of low SNR caused by rough surface of AM components. The minimum detectable defect reaches 0.1 mm and the quantitative error could low down to 6.46% when the defect size is larger than 0.2 mm. Compared with the C-scan imaging method, the method proposed in this paper can improve the scanning efficiency of single-layer inspection by more than 300%, which is meaningful to improve the efficiency of metal additive manufacturing.
With the ever‐increasing demand for wearable electronics and energy‐saving technologies, self‐powered thermoelectric personal thermal management (PTM) has attracted extensive research interest. In ...this review, the unique characteristics of thermoelectric PTM comparing with other technologies are first highlighted, and the key parameters and fundamental functions of thermoelectric PTM are systematically summarized. Then, the advances in thermoelectric PTM are overviewed from the material design to the wearable device design viewpoints. Finally, the key challenges and future research directions of thermoelectric PTM, where both high‐performance flexible materials and proper device designs are in urgent need, are pointed out. This review will deliver a systematic understanding and guideline for thermoelectric PTM.
The increasing demand for wearable electronics has boosted the development of energy‐saving and self‐powered personal thermal management systems. This review highlights the unique advantages of thermoelectric technology comparing with other technologies, summarizes corresponding key parameters, fundamental functions, material and device advancements of thermoelectric personal thermal management, and further points out corresponding future research directions.
Thermal ablation of localized prostate tumors via endocavitary Ultrasound-guided High Intensity Focused Ultrasound (USgHIFU) faces challenges that could be alleviated by better integration of dual ...modalities (imaging/therapy). Capacitive Micromachined Ultrasound Transducers (CMUTs) may provide an alternative to existing piezoelectric technologies by exhibiting advanced integration capability through miniaturization, broad frequency bandwidth and potential for high electro-acoustic efficiency. An endocavitary dual-mode USgHIFU probe was built to investigate the potential of using CMUT technologies for transrectal prostate cancer ablative therapy. The USgHIFU probe included a planar 64-element annular HIFU CMUT array ( fHIFU = 3 MHz) surrounding a 256-element linear imaging CMUT array. Acoustic characterization of the HIFU array included 3D pressure field mapping and radiation force balance measurements. Ex vivo proof-of-concept experiments consisted in generating HIFU thermal ablations with the CMUT probe on porcine liver tissues. The planar CMUT probe enabled HIFU dynamic focusing (distance range: 32 - 72 mm) while providing acoustic surface intensities of 1 W/cm 2 that allowed producing elementary ex vivo ablations in depth of liver tissue (L×W ≈ 10 mm × 5 mm). Combinations of dynamic focusing, along with probe rotation and translation produced larger thermal ablations (L×W ≈ 20 mm × 20 mm) by juxtaposing multiple elementary ablations, consistent with expected results obtained through numerical modeling. The technical feasibility of using a USgHIFU probe, fully-developed using CMUTs for tissue ablation purposes, was demonstrated. The HIFU-CMUT array showed tissue ablation capabilities with volumes compatible with localized cancer targeting thus providing assets for further development of focal therapies.
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