Current‐density–voltage (J–V) hysteresis in perovskite solar cells (PSCs) is a critical issue because it is related to power conversion efficiency and stability. Although parameters affecting the ...hysteresis have been already reported and reviewed, little investigation is reported on scan‐direction‐dependent J–V curves depending on perovskite composition. This review investigates J–V hysteric behaviors depending on perovskite composition in normal mesoscopic and planar structure. In addition, methodologies toward hysteresis‐free PSCs are proposed. There is a specific trend in hysteresis in terms of J–V curve shape depending on composition. Ion migration combined with nonradiative recombination near interfaces plays a critical role in generating hysteresis. Interfacial engineering is found to be an effective method to reduce the hysteresis; however, bulk defect engineering is the most promising method to remove the hysteresis. Among the studied methods, KI doping is proved to be a universal approach toward hysteresis‐free PSCs regardless of perovskite composition. It is proposed from the current studies that engineering of perovskite film near the electron transporting layer (ETL) and the hole transporting layer (HTL) is of vital importance for achieving hysteresis‐free PSCs and extremely high efficiency.
Photocurrent–voltage hysteresis in perovskite solar cells (PSCs) induced by ion migration combined with nonradiative recombination near the interface depends on perovskite composition and device structure. Among the methods used in the attempt to reduce the hysteresis, potassium‐ion doping is found to be a universal approach toward hysteresis‐free PSCs regardless of perovskite composition.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
High‐quality perovskite monocrystalline films are successfully grown through cavitation‐triggered asymmetric crystallization. These films enable a simple cell structure, ITO/CH3NH3PbBr3/Au, with near ...100% internal quantum efficiency, promising power conversion efficiencies (PCEs) >5%, and superior stability for prototype cells. Furthermore, the monocrystalline devices using a hole‐transporter‐free structure yield PCEs ≈6.5%, the highest among other similar‐structured CH3NH3PbBr3 solar cells to date.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
This pilot study aimed to investigate the immediate impact of low-intensity exercises with blood flow restriction (BFR) on older adults with knee osteoarthritis (KOA). Fifteen patients with KOA who ...were over 50 years old, participated and underwent low-intensity resistance knee exercises at 30% of their one-repetition maximum with BFR three times/week for two weeks. Pre- and post-exercise assessments included pain levels, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, isokinetic knee strength, lower extremity muscle volume (via leg circumference and muscle thickness), functional performance tests (timed up-and-go TUG and sit-to-stand STS), skeletal muscle index (SMI) using bioelectrical impedance analysis, and handgrip strength (HGS). Post-exercise, there was a significant reduction in pain. WOMAC scores showed significant improvements across all three domains: pain, stiffness, and physical function. In the TUG and STS tests, completion times were significantly reduced. Thigh and calf circumferences, as well as thigh muscle thickness significantly increased after exercise. Post-exercise SMI and HGS also significantly increased. However, isokinetic knee strength did not show significant changes. In conclusion, low-intensity BFR exercises provide immediate benefits in symptoms and physical performance for patients with KOA, potentially inducing local and systemic muscle mass increase, even after a short-term intervention.
Electrochemical sodium storage and capture are considered an attractive technology owing to the natural abundance, low cost, safety, and cleanness of sodium, and the higher efficiency of the ...electrochemical system compared to fossil‐fuel‐based counterparts. Considering that the sodium‐ion chemistry often largely deviates from the lithium‐based one despite the physical and chemical similarities, the architecture and chemical structure of electrode materials should be designed for highly efficient sodium storage and capture technologies. Here, the rational design in the structure and chemistry of carbon materials for sodium‐ion batteries (SIBs), sodium‐ion capacitors (SICs), and capacitive deionization (CDI) applications is comprehensively reviewed. Types and features of carbon materials are classified into ordered and disordered carbons as well as nanodimensional and nanoporous carbons, covering the effect of synthesis parameters on the carbon structure and chemistry. The sodium storage mechanism and performance of these carbon materials are correlated with the key structural/chemical factors, including the interlayer spacing, crystallite size, porous characteristics, micro/nanostructure, morphology, surface chemistry, heteroatom incorporation, and hybridization. Finally, perspectives on current impediment and future research directions into the development of practical SIBs, SICs, and CDI are also provided.
The key aspects of designing the structure and chemistry of carbon materials are comprehensively reviewed for applications such as sodium‐ion batteries, sodium‐ion capacitors, and capacitive deionization. The classification and features of carbon materials into graphitic and disordered carbons are described, as well as nanodimensional and nanoporous carbons, covering the correlation of structure and chemistry with electrochemical properties, and perspectives in electrochemical sodium‐ion storage and capture.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A highly scalable synapse device based on a junctionless (JL) ferroelectric (FE) FinFET is presented for neuromorphic applications. The synaptic behaviors of the JL ...metal-ferroelectric-insulator-silicon FinFET were experimentally demonstrated after verifying the ferroelectric characteristics of the HfZrO X (HZO) film using a metal-ferroelectric-metal capacitor. The fabricated synapse showed distinguishable polarization switching behaviors with gradually controllable channel conductance. From neural network simulations using the proposed JL FE FinFET as synapses, the pattern recognition accuracy for hand-written digits was validated to be approximately 80% for neuromorphic applications.
Flexible and self‐powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self‐powered and flexible PD based ...on the methylammonium lead iodide (CH3NH3PBI3) perovskite is demonstrated. Such a self‐powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high‐quality CH3NH3PBI3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 1013 Jones. In the self‐powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW−1 cm−2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self‐powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real‐world sensing capability, suggests a new direction for next‐generation optical communications, sensing, and imaging applications.
A flexible and self‐powered organometallic halide perovskite photodetector is demonstrated that features an impressive detectivity of 1.22 × 1013 Jones and a large responsivity of up to 79.4 V mW−1 cm2. These results demonstrate a promising approach for developing a flexible and self‐powered photodetector featuring high detectivity, responsivity, and excellent compatibility in various situations, particularly for outdoor applications.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
An ultrahigh performance MoS2 photodetector with high photoresponsivity (1.94 × 106 A W–1) and detectivity (1.29 × 1012 Jones) under 520 nm and 4.63 pW laser exposure is demonstrated. This ...photodetector is based on a methyl‐ammonium lead halide perovskite/MoS2 hybrid structure with (3‐aminopropyl)triethoxysilane doping. The performance degradation caused by moisture is also minimized down to 20% by adopting a new encapsulation bilayer of octadecyltrichlorosilane/polymethyl methacrylate.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Electrochemical capacitors charge and discharge more rapidly than batteries over longer cycles, but their practical applications remain limited due to their significantly lower energy densities. ...Pseudocapacitors and hybrid capacitors have been developed to extend Ragone plots to higher energy density values, but they are also limited by the insufficient breadth of options for electrode materials, which require materials that store alkali metal cations such as Li
+
and Na
+
. Herein, we report a comprehensive and systematic review of emerging anion storage materials for performance- and functionality-oriented applications in electrochemical and battery-capacitor hybrid devices. The operating principles and types of dual-ion and whole-anion storage in electrochemical and hybrid capacitors are addressed along with the classification, thermodynamic and kinetic aspects, and associated interfaces of anion storage materials in various aqueous and non-aqueous electrolytes. The charge storage mechanism, structure-property correlation, and electrochemical features of anion storage materials are comprehensively discussed. The recent progress in emerging anion storage materials is also discussed, focusing on high-performance applications, such as dual-ion- and whole-anion-storing electrochemical capacitors in a symmetric or hybrid manner, and functional applications including micro- and flexible capacitors, desalination, and salinity cells. Finally, we present our perspective on the current impediments and future directions in this field.
Emerging trends in anion storage materials are reviewed, focusing on the classification, storage mechanisms, and electrochemical features of anion storage materials in various electrolytes for electrochemical capacitors in a symmetric or hybrid manner.
A myriad of studies and strategies have already been devoted to improving the stability of perovskite films; however, the role of the different perovskite crystal facets in stability is still ...unknown. Here, we reveal the underlying mechanisms of facet-dependent degradation of formamidinium lead iodide (FAPbI
) films. We show that the (100) facet is substantially more vulnerable to moisture-induced degradation than the (111) facet. With combined experimental and theoretical studies, the degradation mechanisms are revealed; a strong water adhesion following an elongated lead-iodine (Pb-I) bond distance is observed, which leads to a δ-phase transition on the (100) facet. Through engineering, a higher surface fraction of the (111) facet can be achieved, and the (111)-dominated crystalline FAPbI
films show exceptional stability against moisture. Our findings elucidate unknown facet-dependent degradation mechanisms and kinetics.
PDF
