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Effect of hydrodynamic conditions on the Cu(In,Ga)Se2 thin film growth by electrodeposition
摘要： In this paper, an experimental study about CIGS thin film growth due to hydrodynamic conditions variations on the working electrode surface is reported. Local hydrodynamic conditions were produced by the interaction of the natural convection flow with a non-conducting hemisphere placed on the working electrode surface. The electrodeposition process was made by a single bath with copper, indium, gallium and selenium ions to obtain CIGS thin films. The electrodes in the electrolytic cell were placed vertically. The as-electrodeposited CIGS thin film morphology near the hemisphere had a characteristic growth as a consequence of the local hydrodynamic conditions. CIGS thin film morphology and composition variations due to the wake and boundary layer were identified. With the CIGS film morphology obtained due to the presence of the wake was possible to represent the natural convection flow pattern on the Mo electrode surface. The CIGS thin film composition, inside and outside of the wake and throughout the boundary layer, was characterized. The gallium incorporation to the CIGS film was principally affected. As a consequence of this study, it was found that the atomic percentage of gallium in the CIGS film is related to deposition current density.
关键词： Electrodeposition,CIGS thin film,Natural convection flow
更新于2025-09-23 15:22:29
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Color tuning in Cu(In,Ga)Se <sub/>2</sub> thin-film solar cells by controlling optical interference in transparent front layers
摘要： Aesthetic factors such as colorization in harmony with the surrounding environment are becoming important in the field of applied photovoltaics. Therefore, there exists a need to realize colors in solar cells, with minimum additional cost and efficiency loss. We tuned the color of Cu(In,Ga)Se2 thin-film solar cells by controlling the optical interference between the sputtered Zn(O,S) buffer layer and indium tin oxide (ITO) transparent electrode layer, which are intrinsic components of the solar cell device, without any additional process and/or material. The nontoxic Cd-free buffer layer was prepared in consideration of the environmental factor. In order to minimize the degradation of the photovoltaic performance of the solar cell, the experiment was conducted within the thickness (optical path length) of the Zn(O,S) and ITO transparent front layers, which affected the solar cell performance more optically and less electrically. As the antireflection coating thickness increased, the solar cell was calculated to have a wider color range, lower luminosity, and lower JSC loss. Relatively even efficiencies were obtained with a wide color range.
关键词： color,transparent front layer,optical interference,CIGS thin-film solar cell,nontoxic Cd-free buffer
更新于2025-09-23 15:21:01
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Nanosecond laser scribing for see‐through CIGS thin film solar cells
摘要： Building‐integrated photovoltaic (BIPV), especially in a semitransparent and/or see‐through configuration, has attracted significant attention because of the extended surfaces available for the photovoltaic (PV) installation including roofs, facades, and windows. In this study, we examine the P4 scribing process for fabricating see‐through cells on a new Cu (In,Ga)Se2 (CIGS) architecture with indium tin oxide (ITO) bottom contact, using a nanosecond laser beam of 532‐nm wavelength illuminated from glass substrate side. Through parametric studies with the variations of laser beam spot size and pulse energy, we have identified that enlarged laser beam with the pulse energy near scribing threshold could suppress both damage in ITO and electrical shunt induced by molten CIGS. Scanning electron microscopy (SEM) and energy‐dispersive X‐ray spectroscopy (EDS) analyses unveil that the molten CIGS mediated shunt mechanism, wetting the scribing edge and forming Cu‐rich metallic phase. The P4 scribing process operated near threshold fluence of enlarged laser beam clearly suppressed unwanted shunt, also minimizing the fluctuation in the desired film removal trend. Thermal analysis supports that enlarged laser beam enables scribing at reduced CIGS‐ITO interface temperature assisted by buckling‐based film delamination mechanism and also suppresses CIGS melting at scribing edge and its neighborhood. See‐through cells fabricated for the areal fraction of approximately 15% using the optimal laser scribing parameters exhibited the short circuit current reduction rate of 16.8% enabled by the low shunt resistance reduction rate of approximately 8%. Further studies are underway to elucidate precise shunt‐related scribing mechanism on the basis of the cross‐sectional analyses and time‐resolved diagnostics and to fabricate the module level see‐through PV architectures.
关键词： nanosecond laser,laser scribing,CIGS thin film solar cell,see‐through solar cell
更新于2025-09-12 10:27:22
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Physics of Energy Conversion () || 10. Photovoltaic energy conversion
摘要： In a photovoltaic device, solar energy is converted into electricity along a path very different from the one taken in a solarthermal power plant. Here, in a first step the energy of the solar photons is converted into chemical energy in a solid state absorber. This means that the absorber is brought into an electronically excited state involving a reconfiguration of its charge carriers by the generation of electron/hole (e?/h+)-pairs, i.e. by the following reaction: Ground state + ?? → e? + h+. Here, ?? represents a photon with sufficient energy to bring an electron to the excited state. The chemical energy of the charge carrier ensembles in the conduction and valence bands is then converted into electrical energy by spatially separating the e?/h+-pairs via electrical contacts of the absorber which are electron or hole selective, respectively. In general such selective contacts can only be realized by a jump in the material properties between the two contacts, an example for this being a pn-junction. Since under illumination electrons and holes have different electrochemical potentials in the absorber material, this separation leads to a voltage drop between the contacts selective for the different charge carrier types. It is thus the selectivity of the contacts that introduces the built-in asymmetry into the solar cell, making it a usable voltage source (see Section 5.2). This basic working principle is true for all types of solar cells, ranging from conventional solar cells built from crystalline silicon (c-Si) over thin film solar cells fabricated from different materials such as, e.g. Cu(In,Ga)Se2 (CIGS) to organic or dye sensitized solar cells, and is schematically shown in Figure 10.1.
关键词： electricity,solid state absorber,solar energy,photovoltaic,pn-junction,dye sensitized solar cells,organic solar cells,CIGS,thin film solar cells,crystalline silicon,electron/hole pairs
更新于2025-09-11 14:15:04