1,721,218 research outputs found
On the effect of deep defects on the Voc deficit in high-GGI CIGS absorbers: A numerical study
No full textUsing numerical simulations, we investigate the effect of a deep donor known to exist at EV + 1.33 eV, as a contribution to explain the large VOC deficit of Ga-rich absorbers.. We find that uniform GGI absorbers with GGI > 0.5 suffer for the presence of this deep donor, with the VOC deficit linearly increasing with GGI. On the other hand, simulations indicate that this deep donor is unlikely to be a significant performance limiter in double-graded cells
Simulation of the effect of grain-boundaries in backside-passivated CIGS solar cells
Full text linkWe carry out numerical 3D simulations of CIGS cells with back-side Al2O3 passivation and point contact openings in the presence of grain boundaries in the absorber. We consider CIGS cells with different absorber thickness, from 0.35 to 3 mu mathrm{m}. For thinner absorbers (1 mu mathrm{m} or less) we observe that GBs terminating on the Al2O3 are completely or almost completely passivated, while the effectiveness of the passivation decreases for thicker absorbers. GBs terminating on the point contact, instead, significantly lower the efficiency, regardless of absorber thickness. The presence of grain boundaries and the dimension of grains should therefore be taken into consideration when optimizing the back-side point contact array geometry
Color-Performance Dynamics in CIGS Solar Cells with Varied ITO and Zn(O,S) Layer Thickness Explored by Numerical Simulations
No full textThin-film solar cells can be manufactured in various colors, making them more visually appealing for certain applications, such as building facades or public spaces. One method for producing colored thin-film solar cells is to adjust the thickness of the transparent layers in the cell to manipulate optical interference. However, the color of the cell can affect its efficiency. In this study, we utilize electro-optical simulations to determine the cell efficiency of CIGS solar cell at various ITO and Zn(O,S) thicknesses, and evaluate the corresponding color with a dedicated open source software
Impact of constant and pulsed active balancing current patterns on the aging of lithium-ion batteries
No full textLithium-ion batteries (LIB) have been widely used in electric vehicles for the past decade because of their advantageous
properties, such as low self-discharge, high power and energy density, long life, wide operating
temperature range, and lack of memory effect. However, the available energy and power deteriorate because of
inconsistent operations caused by various external factors. For stable operation, it is crucial to focus on the
accurate assessment of the state of health (SOH) of LIB, which is a challenging task. This article presents an
investigation of the effect of different current patterns (constant- and pulsed-current discharge) on battery
performance. Constant current (CC) and pulsed current (PC) cycles were used to represent possible current
battery patterns to be used during active cell balancing. This analysis was conducted using a simple and costeffective
method that aims to measure the battery capacity directly by integrating current over time. The
findings indicate higher capacity retention and lower thermal stress when the LIB is cycled under PC discharge
than under CC discharge. To thoroughly explore the effects of both current patterns, a comparative analysis of
the capacity fade and change in internal resistance is considered. Compared with CC discharge, the capacity fade
and power loss due to increase in resistance were relatively improved by 2 % and 8.7 %, respectively, under PC
discharge. These results show that PC is preferable in active balancing solutions to preserve the LIB lifetime and
performance
Differences of CIGS cell performance with Zn(O, S)/(Zn, Mg)O or CdS/i-ZnO buffers system explored by numerical simulations
No full textStarting from the standard layer sequence of Mo/Cu(In, Ga)Se2/CdS/i-ZnO/ZnO:Al the cell n-side has been modified by replacing the CdS/i-ZnO with Zn(O, S) buffer in combination with (Zn, Mg)O as high-resistive layer, without changing the CIGS bulk. Measurements show a reduction of the cell performance compared to CdS/i-ZnO structure. In order to investigate the observed behavior, numerical simulations are used to examine the effect of the CIGS/Zn(O, S) interface properties on the cell performance. In particular, since the two sets of cells share the same CIGS, the effects on the solar cell's figures of merit of variations of the conduction band offset and defects properties at the buffer/absorber interface are analyzed
A simulation study on the effect of sodium on grain boundary passivation in CIGS thin-film solar cells
Full text link3D numerical simulations of CIGS thin-film solar cells with different grain-boundary (GB) characteristics have been carried out in order to investigate the effect of defect properties and band edge shifts at GBs on the cell performance. Simulation results are compared with experimental data taken on cells with and without NaF post deposition treatment. GBs with different energy gaps and defect properties have been analyzed. Simulations support the idea that the detrimental effect of defective GBs on the cell performance might be reduced by a treatment with Na. The results of this study can help with the interpretation of experimental findings
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
