Search results for " Solar"
showing 10 items of 958 documents
Enamine-based hole transporting materials for vacuum-deposited perovskite solar cells
2020
In a short period of time, the rapid development of perovskite solar cells attracted a lot of attention in the science community with the record for power conversion efficiency being broken every year. Despite the fast progress in power conversion efficiency there are still many issues that need to be solved before starting large scale commercial applications, such as, among others, the difficult and costly synthesis and usage of toxic solvents for the deposition of hole transport materials (HTMs). We herein report new enamine-based charge transport materials obtained via a simple one step synthesis procedure, from commercially available precursors and without the use of expensive organomet…
Impurity analyses of silicon wafers from different manufacturing routes and their impact on LID of finished solar cells
2013
Summarizes the measurements of impurity concentrations in directionally solidified silicon ingots from different feedstocks. The substitutional Carbon and interstitial Oxygen are measured on as-sawn wafers using FTIR. Active iron concentration is mapped on a-Si:H passivated wafers. It is observed that these impurities present in Elkem Solar Grade Silicon (ESS™) concentrations are comparable to the standard polysilicon which are in the acceptable ranges for silicon for solar industry. The measured LID of the finished solar cells is also comparable.
Irradiance Dependent Temperature Coefficients for MC Solar Cells from Elkem Solar Grade Silicon in Comparison with Reference Polysilicon
2014
Abstract An increase in sun intensity enhances the output power of the solar cells, but at the same time the rise of cell temperature affects its electrical performance negatively. The present authors have made a comparative study on temperature coefficients at various irradiances of multicrystalline solar cells made from the standard Siemens process and from material produced by a metallurgical route – the Elkem Solar Silicon (ESS®) process. Such temperature coefficients measured while exposed to various irradiance levels are essential to build a better understanding and prediction of field performance of solar cells manufactured from various feedstock types. In the current experiment, the…
UV-induced Degradation Study of Multicrystalline Silicon Solar Cells Made from Different Silicon Materials
2013
Abstract The effect of ultraviolet-induced degradation (UV-ID) on solar cells made from two different solar grade materials has been compared. By using identical wafer and cell production units, effects originating in the two materials; solar grade produced by the Elkem Solar method (ESS™) was compared to standard polysilicon solar cells. Silicon wafers were selected precisely from similar positions from respective silicon bricks to process identical standard solar cells. The quantum efficiency maps at particular laser wavelengths and IV parameters of all solar cells were measured before and after UV-ID to visualize defects sites in the solar cells and to observe the extent of degradation. …
Energy level determination in bulk heterojunction systems using photoemission yield spectroscopy: case of P3HT:PCBM
2018
Financial support provided by Scientific Research Project for Students and Young Researchers Nr. SJZ2015/20 realized at the Institute of Solid State Physics, University of Latvia, is greatly acknowledged. This work has been supported by the Latvian State Research Program on Multifunctional Materials IMIS2. Jennifer Mann from Physical Electronics is greatly acknowledged for providing UPS data.
Effects of Frequency Dependence of the External Quantum Efficiency of Perovskite Solar Cells
2018
Perovskite solar cells are known to show very long response time scales, on the order of milliseconds to seconds. This generates considerable doubt over the validity of the measured external quantum efficiency (EQE) and consequently the estimation of the short-circuit current density. We observe a variation as high as 10% in the values of the EQE of perovskite solar cells for different optical chopper frequencies between 10 and 500 Hz, indicating a need to establish well-defined protocols of EQE measurement. We also corroborate these values and obtain new insights regarding the working mechanisms of perovskite solar cells from intensity-modulated photocurrent spectroscopy measurements, iden…
CO2 reduction by C3N4-TiO2 Nafion photocatalytic membrane reactor as a promising environmental pathway to solar fuels
2019
Abstract We investigated CO2 photocatalytic reduction coupling, for the first time in literature, the assets offered by the continuous operating mode using C3N4-TiO2 photo-catalyst embedded in a dense Nafion matrix. The reactor performance was analyzed under UV–vis light in terms of productivity, selectivity and converted carbon. Reaction pressure was specifically investigated for its effect as a “driver” in determining reactor performance, modulating products removal from the reaction volume. In addition, the membrane reactor performance was explored as a function of H2O/CO2 feed molar ratio and contact time. The higher feed pressure (5 bar) led to a lesser MeOH production and a greater am…
Parked electric car's cabin heat management using photovoltaic powered ventilation system
2019
Abstract This paper explores the use of electric car roof mounted photovoltaic (PV) powered ventilation for cabin heat management/ventilation. A fully-functional Renault Zoe electric car has been used for performance evaluation of parked electric car ventilation directly powered by PV. This work has been part of a research project of testing electric cars in the urban environment and it has been conducted at the Edinburgh Napier University’s Transport Research Institute. In this work, parked electric car ventilation has been reported, when roof-mounted PV modules were used to operate DC powered fans for ventilation. It has been found that the DC motor-fan selection for removing the hot air …
ITO top-electrodes via industrial-scale PLD for efficient buffer-layer-free semitransparent perovskite solar cells
2022
The deposition of transparent conductive oxides (TCO) usually employs harsh conditions that are frequently harmful to soft/organic underlayers. Herein, successful use of an industrial pulsed laser deposition (PLD) tool to directly deposit indium tin oxide (ITO) films on semitransparent vacuum-deposited perovskite solar cells without damage to the device stack is demonstrated. The morphological, electronic, and optical properties of the PLD deposited ITO films are optimized. A direct relation between the PLD chamber pressure and the solar cell performance is obtained. The semitransparent perovskite solar cells prepared exclusively by vacuum-assisted techniques had fill factors of 78% and exc…
An analysis of direct solar transmittance and atmospheric turbidity in the Mediterranean climatic belt
1989
Abstract The empirical model developed by King and Buckius for the direct transmission in clear sky is applied to hourly data of two Yugoslav locations exhibiting typical meteoclimatic characteristics common to the whole Mediterranean belt. The occurrence of “very clear”, “clear” and “very hazy” hours, after the usually accepted definitions, is determined and discussed. The degree of accuracy of the previsional model is investigated performing the comparison with the corresponding values obtained directly by energetic procedure. A general overestimate of the transmittance is experienced with notable deviations in meteorological conditions affected by the presence of dense clouds which behav…