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Atsushi Fukui Ryoichi Komiya Ryohsuke Yamanaka Ashraful Islam Liyuan Han 《Solar Energy Materials & Solar Cells》2006,90(5):649-658
The effect of the iodide/triiodide redox electrolyte in various organic solvents on the photoelectrochemical properties of bis(tetrabutylammonium) cis-bis(thiocyanato)bis(4-carboxy-2,2′-bipyridine-4′-carboxylato)ruthenium(II)-sensitized nanocrystalline TiO2 solar cells was studied. Solvents with large donor numbers dramatically enhanced the open-circuit voltage (Voc), but usually reduced the short-circuit photocurrent density (Jsc). For a mixed solvent of tetrahydrofuran (THF) and acetonitrile, Voc increased and the fill factor decreased with increasing THF concentration, but Jsc remained relatively constant. As the partial charge of the N or O atom of the solvent molecule increased, Voc increased, but Jsc was unchanged up to a certain value of the partial charge (for THF, −0.46). For cells using 0.3 M 4-tert-butylpyridine and 20 vol% THF in the electrolyte, a short-circuit photocurrent density of 18.23 mA cm−2, an open-circuit voltage of 0.73 V, a fill factor of 0.73, and an overall conversion efficiency of 9.74% were obtained. 相似文献
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Md. Akhtaruzzaman H.N.M. Ekramul Mahmud Ashraful Islam Ahmed Ei Shafei Mohammed Rezaul Karim Kamaruzzaman Sopian Liyuan Han Yoshinori Yamamoto 《Materials Chemistry and Physics》2013
A simple metal-free donor–acceptor type sensitizer U01, bearing strong electron donor indoline-triphenylamine was synthesized for panchromatic sensitization of TiO2 nanocrystalline film. Photovoltaic properties of U01 showed remarkably enhanced light harvesting due to the presence of strong electron donor and robust structure. The new U01 sensitized solar cell exhibited a photovoltaic performance: a short-circuit photocurrent density (Jsc) of 10.70 mA cm−2, an open-circuit photovoltage (Voc) of 0.758 V and a fill factor (FF) of 0.74, corresponding to an overall conversion efficiency of 6.01% under standard global AM 1.5 solar light condition. Our results suggest that indoline-triphenylamine based robust D–A molecular architecture is a highly promising class of panchromatic sensitizers for improvement of the performance of dye-sensitized solar cells (DSCs). 相似文献
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In this paper, a dual iris-based biometric identification system that increases the accuracy and the performance of a typical human iris recognition system is proposed. This system detects, isolates, and extracts the iris region from the eye images and maps the circular regions into rectangular polar coordinates according to the preset radial and angular resolutions. The phase responses, obtained from convolving the polar images with 1D log Gabor filter, are quantized to generate the binary iris templates which are compared using the hamming distance. Unlike the conventional method which examines a single eye, the proposed method takes images from both eyes simultaneously. Using it on CASIA Iris database V3, false positive rate and false negative rate were found to be 0 and 9.96 %, respectively, while the overall accuracy was 99.92 %. 相似文献
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Shohag Md. Bodhroddoza Hossain Md. Sayed Hasan Md. Rakibul Ahmed Md. Mobasher Al Mahmud Abdullah Uddin Mohammad Mezbah Soner Md. Abdul Malek Haque Ashraful Khan Kamrul Alam 《Microsystem Technologies》2022,28(12):2785-2793
Microsystem Technologies - Bangladesh Atomic Energy Commission TRIGA Research Reactor (BTRR) is a MK II type nuclear research reactor with a maximum thermal output power of 3 MW. Nuclear... 相似文献
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Md Ashiqur Rahman Laskar Wenqin Luo Nabin Ghimire Ashraful Haider Chowdhury Behzad Bahrami Ashim Gurung Khan Mamun Reza Rajesh Pathak Raja Sekhar Bobba Buddhi Sagar Lamsal Ke Chen Md Tawabur Rahman Sheikh Ifatur Rahman Khalid Emshadi Tingting Xu Mao Liang Wen‐Hua Zhang Qiquan Qiao 《Advanced functional materials》2020,30(22)
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. 相似文献
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Xingshu Sun Raghu Vamsi Krishna Chavali Muhammad Ashraful Alam 《Progress in Photovoltaics: Research and Applications》2019,27(1):55-66
The uncertainties associated with technology‐specific and geography‐specific degradation rates make it difficult to calculate the levelized cost of energy, and thus the economic viability of solar energy. In this regard, millions of fielded photovoltaic modules may serve as a global testbed, where we can interpret the routinely collected time series maximum power point (MPP) data to assess the time‐dependent “health” of solar modules. The existing characterization methods, however, cannot effectively mine/decode these datasets to identify various degradation pathways. In this paper, we propose a new methodology called the Suns‐Vmp method, which offers a simple yet powerful approach to monitoring and diagnosing time‐dependent degradation of solar modules by using the MPP data. The algorithm reconstructs “IV” curves by using the natural illumination‐dependent and temperature‐dependent daily MPP characteristics as constraints to fit physics‐based circuit models. These synthetic IV characteristics are then used to determine the time‐dependent evolution of circuit parameters (eg, series resistance), which in turn allows one to deduce the dominant degradation modes (eg, solder bond failure) of solar modules. The proposed method has been applied to a test facility at the National Renewable Energy Laboratory. Our analysis indicates that the solar modules degraded at a rate of ~0.7%/year because of discoloration and weakened solder bonds. These conclusions are validated by independent outdoor IV measurements and on‐site imaging characterization. Integrated with physics‐based degradation models or machine learning algorithms, the method can also serve to predict the lifetime of photovoltaic systems. 相似文献
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Electrowetting-induced microwater droplet transports in parallel-plate and open-plate electrowetting-on-dielectrode (EWOD) have been studied numerically. The governing equations for three-dimensional transient microfluidic flow are solved by a finite volume scheme with a two-step projection method on a fixed computational domain. The free surface of the droplet is tracked by the coupled level set and volume-of-fluid (CLSVOF) method with the surface tension force determined by the continuum surface force (CSF) model. The results of the numerical model have been validated with published experimental data and the physics of droplet transport have been investigated. A parametric study has been performed in which the effects of voltage amplitude, channel gap, and electrode size have been examined. 相似文献
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The Chemical Reactor Engineering Center – Gas Solid – Optiprobes (CREC-GS-Optiprobe) can be used to determine particle cluster properties in down flow reactors. These properties include solid hold-up, cluster size and cluster velocity. Critical to this task is the determination of the “focal region”. It is established in this study that the CREC-GS Optiprobes display an “effective focal region” smaller than the focal region calculated using geometrical and optical considerations. In this respect, an “effective focal region” of 118 μm with a standard deviation of 34 μm is established on the basis of different considerations including experimental observations. The existence of this “effective focal region” is most valuable in downer units given it makes the CREC-Optiprobe a suitable tool for measurements of clusters sizes with an average diameter of 84 μm FCC particles as well as local solid concentration. 相似文献