An efficient Si/PEDOT:PSS hybrid solar cell using synergistic surface texturing of Si nanowires (SiNWs) on pyramids is demonstrated. A power conversion efficiency (PCE) of 9.9% is achieved from the ...cells using the SiNW/pyramid binary structure, which is much higher than similar cells based on planar Si, pyramid‐textured Si, and SiNWs. The PCE is the highest reported to‐date for hybrid cells based on Si nanostructures and PEDOT.
This study aims to examine the positive and negative factors that can significantly explain user acceptance of mobile commerce (m-commerce) in Macau. A technology acceptance model for m-commerce with ...five factors is constructed. The proposed model is tested using data collected from 219 respondents. Confirmatory factor analysis is performed to examine the reliability and validity of the model, and structural equation modelling is performed to access the relationship between behaviour intention and each factor. The acceptance of m-commerce is influenced by factors including performance expectancy, social influence, facilitating conditions and privacy concern; while effort expectancy is insignificant in this case. The results of the study are useful for m-commerce service providers to adjust their strategies for promoting m-commerce services. This study contributes to the practice by providing a user technology acceptance model for m-commerce that can be used as a foundation for future research.
High-efficiency hybrid solar cells are fabricated using a simple approach of spin coating a transparent hole transporting organic small molecule, ...2,2′,7,7′-Tetrakis-(N,N-di-4-methoxyphenylamino)-9,9′-spirobifluorene (Spiro-OMeTAD) on silicon nanowires (SiNWs) arrays prepared by electroless chemical etching. The characteristics of the hybrid cells are investigated as a function of SiNWs length from 0.15 to 5 μm. A maximum average power conversion efficiency of 9.92% has been achieved from 0.35 μm length SiNWs cells, despite a 12% shadowing loss and the absence of antireflective coating and back surface field enhancement. It is found that enhanced aggregations in longer SiNWs limit the cell performance due to increased series resistance and higher carrier recombination in the shorter wavelength region. The effects of the Si substrate doping concentrations on the performance of the cells are also investigated. Cells with higher substrate doping concentration exhibit a significant drop in the incident photons-to-current conversion efficiency (IPCE) in the near infrared region. Nevertheless, a promising short circuit current density of 19 mA/cm2 and IPCE peak of 57% have been achieved for a 0.9 μm length SiNWs cell fabricated on a highly doped substrate with a minority-carrier diffusion length of only 15 μm. The results suggest that such hybrid cells can potentially be realized using Si thin films instead of bulk substrates. This is promising towards realizing low-cost and high-efficiency SiNWs/organic hybrid solar cells.
We present a simple approach of fabricating high-efficiency hybrid solar cells based on silicon nanowires (SiNWs) and a conductive polymer, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate ...(PEDOT:PSS). PEDOT:PSS is directly spin coated on vertical SiNW arrays fabricated by electroless chemical etching to form a core-sheath heterojunction. A silver grid is used as the top anode. Compared to a planar Si/PEDOT:PSS cell, the power conversion efficiency of a 1-cm 2 SiNW/PEDOT:PSS cell increases greatly from 6.2% to 9%. Cells with different SiNW lengths are also studied, and it is found that enhanced aggregation of longer SiNWs leads to poor surface coverage by PEDOT and, hence, degraded solar cell characteristics.
This study aims to empirically examine the trust factors that affect the adoption of Internet-based interorganizational systems (IIOS). A trust model with five trust factors is constructed. The model ...is tested using data gathered from 295 practitioners. Confirmatory factor analysis is used to validate the model, and structural equation modelling is used for data analysis. The adoption of IIOS is influenced by trust factors including usability, reliability and availability, audit and verification mechanisms, and interoperability, while security is insignificant in this case. The generalization of the findings is currently limited, as the subjects were all Chinese people living in Hong Kong. Future studies could study individuals belonging to other types of professions, industries, and cultures to test the generalizability of the model. The study provides a trust model to facilitate practitioners for the effective adoption of IIOS. It also adds a trust model to the literature of IIOS in the electronic supply chain context.
We demonstrate high-efficiency hybrid solar cells based on heterojunctions formed between n-type silicon nanowires (SiNWs) and p-type organic semiconductors fabricated using a simple solution-based ...approach. Two types of devices have been fabricated with different organic materials used, namely poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and a small molecule, 2,2$'$,7,7$'$-tetrakis( N , N -di-4-methoxyphenylamino)-9,9$'$-spirobifluorene (Spiro-OMeTAD). The cells are characterized and compared in terms of their physical characteristics and photovoltaic performance. Using SiNWs of the same length of 0.35 μm, it is found that the SiNWs/Spiro cells exhibit a power conversion efficiency of 10.3%, which is higher than the 7.7% of SiNWs/PEDOT cells. The results are interpreted in terms of the ability of the two organic semiconductors to fill the gaps between the SiNWs and the optical reflectance of the samples. The degradation of the SiNWs/Spiro cells is also studied and presented.
Challenges in fabricating all-perovskite tandem solar cells as modules rather than as single-junction configurations include growing high-quality wide-bandgap perovskites and mitigating irreversible ...degradation caused by halide and metal interdiffusion at the interconnecting contacts. We demonstrate efficient all-perovskite tandem solar modules using scalable fabrication techniques. By systematically tuning the cesium ratio of a methylammonium-free 1.8-electron volt mixed-halide perovskite, we improve the homogeneity of crystallization for blade-coated films over large areas. An electrically conductive conformal "diffusion barrier" is introduced between interconnecting subcells to improve the power conversion efficiency (PCE) and stability of all-perovskite tandem solar modules. Our tandem modules achieve a certified PCE of 21.7% with an aperture area of 20 square centimeters and retain 75% of their initial efficiency after 500 hours of continuous operation under simulated 1-sun illumination.
'Professional Financial Computing Using Excel and VBAis an admirable exposition that bridges the theoretical underpinnings of financial engineering and its application which usually appears as a ...'black-box' software application. The book opens the black-box and reveals the architecture of risk-modeling and financial engineering based on industry-standard stochastic models by utilizing Excel and VBA functionality to create a robust and practical modeling tool-kit. Financial engineering professionals who purchase this book will have a jumpstart advantage for their customized financial engineering and modeling needs.' Dr. Cameron WicentowichVice President, Treasury Analytics Canadian Imperial Bank of Commerce (CIBC)'Spreadsheet modeling for finance has become a standard course in the curriculum of many Quantitative Finance programs since the Excel-based Visual Basic programming is now widely used in constructing optimal portfolios, pricing structured products and managing risks. Professional Financial Computing Using Excel and VBAis written by a unique team of finance, physics and computer academics and practitioners. It is a good reference for those who are studying for a Masters degree in Financial Engineering and Risk Management. It can also be useful for financial engineers to jump-start a project on designing structured products, modeling interest term structure or credit risks.' Dr. Jin ZhangDirector of Master of Finance Program and Associate Professor The University of Hong Kong'Excel has been one of the most powerful tools for financial planning and computing over the last few years. Most users utilize a fraction of its capabilities. One of the reasons is the limited availability of books that cover the advanced features of Excel for Finance. Professional Financial Computing Using Excel and VBAgoes the extra mile and deals with the Excel tools many professionals call for. This book is a must for professionals or students dealing with financial engineering, financial risk management, computational finance or mathematical finance. I loved the way the authors covered the material using real life, hands-on examples.' Dr. Isaac GottliebTemple University Author, Next Generation Excel: Modeling in Excel for Analysts and MBAs
PDF
