High‐quality hole transport layers are prepared by spin‐coating copper doped nickel oxide (Cu:NiO) nanoparticle inks at room temperature without further processing. In agreement with theoretical ...calculations predicting that Cu doping results in acceptor energy levels closer to the valence band maximum compared to gap states of nickel vacancies in undoped NiO, an increase in the conductivity in Cu:NiO films compared to NiO is observed. Cu in Cu:NiO can be found in both Cu+ and Cu2+ states, and the substitution of Ni2+ with Cu+ contributes to both increased carrier concentration and carrier mobility. In addition, the films exhibit increased work function, which together with the conductivity increase, enables improved charge transfer and extraction. Furthermore, recombination losses due to lower monomolecular Shockley‐Read‐Hall recombination are reduced. These factors result in an improvement of all photovoltaic performance parameters and consequently an increased efficiency of the inverted planar perovskite solar cells. A power conversion efficiency (PCE) exceeding 20% could be achieved for small‐area devices, while PCE values of 17.41 and 18.07% are obtained for flexible devices and large area (1 cm2) devices on rigid substrates, respectively.
Copper‐doped Nickel Oxide (Cu:NiO) nanoparticles are synthesized and applied as hole transport layers in perovskite solar cells. Cu doping results in an increase in carrier concentration, hole mobility and work function of Cu:NiO. Consequently, charge extraction is improved and the losses are decreased. The devices with Cu:NiO have better efficiency than NiO, with a highest PCE exceeding 20%.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Organic–inorganic hybrid perovskite solar cells have resulted in tremendous interest in developing next generation photovoltaics due to high record efficiency exceeding 22%. For inverted structure ...perovskite solar cells, the hole extraction layers play a significant role in achieving efficient and stable perovskite solar cell by modifying charge extraction, interfacial recombination losses, and band alignment. Here, cesium doped NiOx is selected as a hole extraction layer to study the impact of Cs dopant on the optoelectronic properties of NiOx and the photovoltaic performance. Cs doped NiOx films are prepared by a simple solution‐based method. Both doped and undoped NiOx films are smooth and highly transparent, while the Cs doped NiOx exhibits better electron conductivity and higher work function. Therefore, Cs doping results in a significant improvement in the performance of NiOx‐based inverted planar perovskite solar cells. The best efficiency of Cs doped NiOx devices is 19.35%, and those devices show high stability as well. The improved efficiency in devices with Cs:NiOx is attributed to a significant improvement in the hole extraction and better band alignment compared to undoped NiOx. This work reveals that Cs doped NiOx is very promising hole extraction material for high and stable inverted perovskite solar cells.
Cesium doping of NiOx enhances the conductivity of the oxide film and the hole extraction from the perovskite film in inverted planar perovskite solar cells. Significantly improved photovoltaic performance is obtained with the best efficiencies of 16.04% and 19.35% for NiOx and Cs:NiOx, respectively. The devices exhibit negligible hysteresis and good stability.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Responsive polymer materials possessing variable mechanical properties have shown promising practical applications, whereas water has clear advantages among the triggers owing to its wide abundance, ...green characteristics, as well as mild conditions involved. However, ubiquitous water‐induced softening would prevent polymer materials from applications with high humidity or aqueous environment. Herein, an unprecedented polymer gel material is reported that exhibits a dramatic and reversible water‐induced stiffening base on phase separation, differing from traditional ones that are usually weakened upon hydration due to the plasticizing effect. The material shows a large stiffness change in Young's modulus (as much as 104 times), which is much larger than that induced by glass transition and comparable to that caused by crystallization‐melting process. The polymer materials are fabricated in a facile way by introducing an ionic liquid and a lithium salt into a poly(benzyl methacrylate) network. Moreover, the volume remains almost unchanged during the reversible soft–stiff transition. A universal approach of water‐induced stiffening is proposed and verified on various systems. As for demonstration, this material is used for humidity‐induced shape memory. This work offers an effective method for developing water‐induced stiffened material and will pave the way toward potential applications for water‐responsive polymer materials.
An unprecedented polymer material with a dramatic and reversible water‐induced stiffening (stiffness increase as much as 104 times) is introduced based on phase separation, differing from traditional ones that are usually weakened upon hydration. A universal approach for water‐induced stiffening is proposed and verified on various systems. This work would pave the way for the design and development of water‐responsive polymer materials.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this study, tests of fit for the power function lognormal distribution is considered. The probability plot, probability plot correlation coefficient, and goodness-of-fit tests-the ...Kolmogorov-Smirnov (KS), Cramér-von Mises (CvM), and Anderson-Darling (AD) tests are provided. Tables of critical values are presented by using simulation techniques, and the AD test outperforms KS and CvM tests based on power comparisons. Finally, to illustrate these test procedures, we fit this distribution to the data which represent the survival times of 121 breast cancer patients from one hospital.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Ni‐rich LiNixCoyMn1−x−yO2 (x ≥ 0.8) layered oxides are the most promising cathode materials for lithium‐ion batteries due to their high reversible capacity of over 200 mAh g−1. Unfortunately, the ...anisotropic properties associated with the α‐NaFeO2 structured crystal grains result in poor rate capability and insufficient cycle life. To address these issues, a micrometer‐sized Ni‐rich LiNi0.8Co0.1Mn0.1O2 secondary cathode material consisting of radially aligned single‐crystal primary particles is proposed and synthesized. Concomitant with this unique crystallographic texture, all the exposed surfaces are active {010} facets, and 3D Li+ ion diffusion channels penetrate straightforwardly from surface to center, remarkably improving the Li+ diffusion coefficient. Moreover, coordinated charge–discharge volume change upon cycling is achieved by the consistent crystal orientation, significantly alleviating the volume‐change‐induced intergrain stress. Accordingly, this material delivers superior reversible capacity (203.4 mAh g−1 at 3.0–4.3 V) and rate capability (152.7 mAh g−1 at a current density of 1000 mA g−1). Further, this structure demonstrates excellent cycling stability without any degradation after 300 cycles. The anisotropic morphology modulation provides a simple, efficient, and scalable way to boost the performance and applicability of Ni‐rich layered oxide cathode materials.
A Ni‐rich LiNi0.8Co0.1Mn0.1O2 cathode material with radially aligned single‐crystal primary particles is synthesized. This unique crystallographic texture enables three‐dimensional (3D) Li+ diffusion channels penetrated straightforwardly from surface to center of the secondary particles and significantly alleviates volume‐change‐induced intergrain stress upon cycling. Accordingly, this material delivers superior capacity, rate capability and excellent cycling stability.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The activated carbon materials from the corn stalk core raw materials were prepared through the carbonization and activation process and applied as electrode in supercapacitor. The biomass carbon ...materials activated under different temperatures were tested by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge cycling method. The corn stalk core-derived material activated at 700 °C with the highest specific surface area (2349.89 m2 g−1) has exhibited the maximum specific capacitance of 140 F g−1. Further detailed characterization and theoretical analysis have demonstrated that the corn stalk core derived activated carbon anode material can not only enhance the capacity of supercapacitor but also realize the comprehensive utilization of corn stalks.
Corn stalk core-derived activated carbonaceous anode material was synthesized by a facile method. Its unique porous structure plays an important role in the improvement of electrochemical performance. Display omitted
•We report a high surface carbon anode material derived from corn stalk core via a facile method.•The environment-friendly method has potential application in biomass waste treatment.•The biomass electrode delivers an excellent cycleability with high capacity and superior rate capability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In this paper, two third-order bandpass filters (BPFs) designed for millimeter-wave applications are presented. Unlike previously published ones, the proposed designs use a "cell-based" approach, ...which utilizes identical broadside-coupled resonators (BCRs) with series and shunt capacitors. The capacitors are mainly used as J-inverters to achieve the desired frequency responses. To fully understand the operational mechanism of the presented approach, both the BCR and BPFs are analyzed using the simplified LC-equivalent circuit models. To prove the concept, both BPFs are implemented in a standard 0.13-μm silicon-germanium bipolar complementary metal-oxide-semiconductor technology. According to the on-wafer measurement results, the BPFs exhibit the excellent performance including flat in-band responses with relatively large harmonic suppression. The first design has a 1-dB bandwidth from 23.9 to 39.7 GHz with an insertion loss of 3.9 dB at the center frequency of 31 GHz. The stopband attenuation is better than 45 dB at 58 GHz. The 1-dB bandwidth of the second design covers from 26.7 to 44.3 GHz with an insertion loss of 3.1 dB at the center frequency of 35 GHz, and stopband attenuation up to 35 dB is achieved at 59 GHz. Both designs occupy an identical area of 0.073 mm 2 (0.248 × 0.294 mm 2 ), excluding the G-S-G testing pads.
Printed electronics is becoming increasingly important in a variety of newly emerging areas. However, restricted to the rather limited conductive inks and available printing strategies, the current ...electronics manufacture is usually confined to industry level. Here, we show a highly cost-effective and entirely automatic printing way towards personal electronics making, through introducing a tapping-mode composite fluid delivery system. Fundamental mechanisms regarding the reliable printing, transfer and adhesion of the liquid metal inks on the substrate were disclosed through systematic theoretical interpretation and experimental measurements. With this liquid metal printer, a series of representative electronic patterns spanning from single wires to desired complex configurations such as integrated circuit (IC), printed-circuits-on-board (PCB), electronic paintings, or more do-it-yourself (DIY) devices, were demonstrated to be printed out with high precision in a moment. And the total machine cost already reached personally affordable price. This is hard to achieve by a conventional PCB technology which generally takes long time and is material, water and energy consuming, while the existing printed electronics is still far away from the real direct printing goal. The present work opens the way for large scale personal electronics manufacture and is expected to generate important value for the coming society.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Dental implants are commonly used to repair missing teeth. The implant surface plays a critical role in promoting osseointegration and implant success. However, little information is ...available about which implant surface treatment technology best promotes osseointegration and implant stability. The aim of this network meta-analysis was to evaluate the osseointegration and stability of four commonly used dental implants (SLA, SLActive, TiUnite, and Osseotite). The protocol of the current meta-analysis is registered in PROSPERO (International Prospective Register of Systematic Reviews) under the code CRD42020190907 (
https://www.crd.york.ac.uk
). We conducted a systematic review following PRISMA and Cochrane Recommendations. Medline (PubMed), Cochrane Library, Embase, and the Web of Science databases were searched. Only randomized controlled trials were considered. Twelve studies were included in the current network meta-analysis, eleven studies were included concerning the osseointegration effect and five studies were included for stability analysis (four studies were used to assess both stability and osseointegration). Rank possibility shows that the SLActive surface best promoted bone formation at an early healing stage and TiUnite seemed to be the best surface for overall osseointegration. For stability, TiUnite seemed to be the best surface. The present network meta-analysis showed that the SLActive surface has the potential to promote osseointegration at an early stage. The TiUnite surface had the best effect on osseointegration regarding the overall healing period. The TiUnite surface also had the best effect in stability.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A pair of coupled stepped-impedance resonators and its use to build single- and dual-band bandpass filter (BPF) is presented. To that end, two symmetrical stepped-impedance resonators with two ...embedded coupled-line sections are used. The adopted resonators are coupled at the two open-ended edges. The first even-mode resonant mode can be suppressed or excited based on whether it is required to realize a single- or dual-band response. Sharp passband selectivity and stopband harmonic suppression are achieved due to the existence of multiple transmission zeros. For verification, single- and dual-band filters using the proposed resonator are designed, fabricated and tested. The experimental results show a passband of 2.34-2.62 GHz (centered at 2.45 GHz for WLAN system), less than 1.5 dB insertion loss for the single-band filter; the dual-band design has two passbands ranged from 2.28-2.67 GHz and 3.35-3.63 GHz with less than 1.2 dB insertion loss for WLAN and WiMAX systems.
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