Phenylhydrazinium Iodide for Surface Passivation and Defects Suppression in Perovskite Solar Cells

In recent years, hybrid perovskite solar cells (HPSCs) have received considerable research attention due to their impressive photovoltaic performance and low‐temperature solution processing capability. However, there remain challenges related to defect passivation and enhancing the charge carrier dynamics of the perovskites, to further increase the power conversion efficiency of HPSCs. In this work, the use of a novel material, phenylhydrazinium iodide (PHAI), as an additive in MAPbI₃ perovskite for defect minimization and enhancement of the charge carrier dynamics of inverted HPSCs is reported. Incorporation of the PHAI in perovskite precursor solution facilitates controlled crystallization, higher carrier lifetime, as well as less recombination. In addition, PHAI additive treated HPSCs exhibit lower density of filled trap states (10¹⁰ cm^?2) in perovskite grain boundaries, higher charge carrier mobility (≈11 × 10^?4 cm² V^?1 s), and enhanced power conversion efficiency (≈18%) that corresponds to a ≈20% improvement in comparison to the pristine devices.     

Image authentication based on robust image hashing with geometric correction

Multimedia Tools and Applications - Image authentication based on robust image hashing has been widely discussed with continuous improvements. However, most of the existing methods misjudge the...     

Penta‐band notched ultra‐wideband monopole antenna loaded with electromagnetic bandgap‐structures and modified U‐shaped slots

In this article, a planar monopole penta‐notched ultra‐wideband (UWB) antenna is designed and investigated. Three notches (2.81 GHz radar surveillance, 3.38 GHz WiMAX, and 3.87 GHz C‐band satellite downlink) have been realized by integrating three modified U‐shaped slots on the radiating surface. Furthermore, to create two additional notches (2.33 GHz ISM band and 5.75 GHz WLAN), two meander line electromagnetic bandgap (EBG); one located near to the feed line and another on the radiating surface, have been introduced in the design. These unit cells play a fundamental role in generating notches at higher as well as lower frequencies. The proposed antenna possesses an overall size of 34.9 × 31.3 × 1.6 mm³ and has been designed over FR4 substrate. A 50 Ω microstrip line is used to feed the antenna. The antenna without any extra arrangement exhibits an impedance bandwidth of 7.6 GHz. A parametric analysis is studied in detail to observe the band rejection characteristics. The ANSYS HFSS simulation software is used for simulating the proposed design structures. For validation purpose, a prototype is fabricated and characterized. A very good agreement is achieved between simulated and measured results.     

Design of high gain,high bandwidth neural amplifier IC considering noise-power trade-off

Microsystem Technologies - Low Noise Neural amplifiers are used for amplifying low amplitude neural spikes in Neural recording systems. The need for low noise is emphasized by the presence of...     

The characterization of metal oxide - Mangifera indica L. matrix and its potential as scavenger of heavy metal pollutant

Widespread pollution by heavy metals requires an efficient, cheap and eco-friendly removal technique. This paper reports the use of discarded leaves of Mangifera indica L. modified to enhance their adsorption efficiency in the removal of heavy metal pollutant. The adsorbent was then characterized through X-ray diffraction study, Fourier transform infrared spectroscopy and application to mathematical models. The adsorption process was found to fit the Langmuir’s isotherm model and pseudo-first-order kinetic model. The intra-particle diffusion model was found to be the rate limiting step for the adsorption process. Its rapid kinetics, high hydrophilicity, and easy regenerability with mild mineral acid (like 0.005 M HCl) make this adsorbent suitable for the fixed bed column technique.     

A new excitation technique for wide-band short backfire antennas

A new excitation technique is developed to improve the impedance bandwidth and to lower the manufacturing cost of a short backfire antenna (SBA). The new excitation structure consists of a planar monopole and a microstrip feed line, both of which are printed on the same dielectric substrate. By splitting the printed monopole with a slot, a wide-band performance can be achieved. The new split-monopole-excited SBA achieves an impedance bandwidth of about 15% [voltage standing wave ratio (VSWR <2)] while maintaining good radiation performance. As an example, an SBA configuration with the new excitation topology was designed and measured at the 5 GHz UNII band, and good agreement was observed between the simulation and experiment. The effects of the geometric parameters of the excitation structure on the impedance performance are investigated and the operating mechanism of the split-monopole-excited SBA is discussed. Being a low-cost, high-gain, and wide-band directional antenna, the new SBA can find applications in various wireless systems, such as LMDS, WLAN, and the emerging WiMAX networks.     

Wideband scalable electrical model for microwave/millimeter waveflip chip interconnects

We present a method for developing fully scalable lumped element models for flip chip interconnects. Measurements of test structures and full wave simulations are used to generate circuit models for various single bump configurations. Furthermore, regression models are developed for scaling the values of the elements with the physical attributes of the circuit. First, the method is validated using only two factors, then the model is extended to more inputs related to the bump geometry and placement. The values of L and C in a simple π model have been scaled with the conductor overlap, the distance from the ground bump to the edge of the ground plane, the width of the CPW launch, the bump height and diameter. Explicit formulas are obtained for L and C as a function of those variables. It has been found that the value of the inductance varies with the conductor overlap, bump height and diameter, while the capacitance is mostly affected by conductor overlap. This paper presents the first fully scalable model for microwave flip chip technology     

W-band double-balanced down-conversion mixer with marchand baluns in silicon-germanium technology

Presented is a monolithic W-band (75-110 GHz) down-conversion mixer consisting of a double-balanced core, Marchand-type on-chip baluns at inputs, and a two-stage output buffer, fabricated in a 200 GHz f _T SiGe technology. Including the loss for input baluns, this mixer exhibits conversion gains of 14.4 plusmn 2.8 dB and single sideband (SSB) noise figures of less than 19.5 dB across the entire W-band, drawing 28 mA from a 3.3 V supply.     

Design of an asymmetrical dual-band WLAN filter in liquid crystal polymer (LCP) system-on-package technology

A single-input-single-output (SISO) dual-band filter operating at ISM 2.4-2.5GHz and UNII 5.15-5.85GHz frequency bands, using the novel "dual behavior resonators" technique has been developed. Exploiting the strong second resonant frequency of resonators to realize the filtering response, allows for achieving the asymmetric shape and the good rejection between the two bands. The insertion loss and return loss at the central frequency are -2.4 dB and -15 dB for the 2.4-GHz band, respectively, and -1.8 dB and -10 dB for the 5-GHz band, respectively. The filter has been fabricated using the novel liquid crystal polymer (LCP) based multilayer packaging technology, enabling a low cost SOP implementation.     

A 20-GHz low-noise amplifier with active balun in a 0.25-/spl mu/m SiGe BICMOS technology

A 20-GHz low-noise amplifier (LNA) with an active balun fabricated in a 0.25-/spl mu/m SiGe BICMOS (f/sub t/=47 GHz) technology was presented by the authors in 2004. The LNA achieves close to 7 dB of gain and a noise figure of 4.9 dB with all ports simultaneously matched to 50 /spl Omega/ with better than -16 dB of return loss. The amplifier is highly linear with an IP/sub 1dB/ of 0 dBm and IIP/sub 3/ of 9 dBm, while consuming 14 mA of quiescent current from a 3.3-V rail, with temperature-compensated biasing. To the authors' knowledge, the LNA delivers the lowest reported noise figure and highest linearity for a silicon implementation of a combined active balun and LNA at 20 GHz, and is the first implementation of an active balun with an LC degenerated emitter-coupled pair. Here we expand on that work, with an analysis of the balun operation and noise optimization of the design.