Yazar "Turan, Rasit" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Yayın
    Enhanced metal assisted etching method for high aspect ratio microstructures: Applications in silicon micropillar array solar cells
    (Pergamon-Elsevier Science Ltd, 2019) Baytemir, Gülşen; Ciftpinar, E. Hande; Turan, Rasit
    A solar cell device, fabricated on high density array cylindrical pillars, enables photogenerated carrier collection in the radial direction, thus shortening the path length of the carriers reaching the junction. It also provides advantages over conventional planar junction solar cells, such as reduced surface reflectance and enhanced light trapping. In this study, highly ordered Si micropillars were fabricated by photolithography and metal assisted etching (MAE) methods. It is shown that the use of ethanol as a solvent during the etching process and increasing HF concentration in the MAE solution both improve the quality of the surfaces of the pillars. Micropillars with smooth sidewalls and a high aspect ratio were obtained in this way. Solar cells with a radial junction were then fabricated on these micropillars. Standard doping, SiO2/SiNx passivation, and metallisation steps were carried out for the fabrication of solar cells with different micropillar lengths. A significant decrease in reflectance values was observed as the micropillar length increased, as expected. Solar cell short circuit current density (J(SC)) and efficiency (eta) of the solar cells tended to increase with micropillar length up to 11.5 mu m and then decrease due to increased surface recombination. The maximum efficiency achieved in this study is 17.26%.
  • Küçük Resim Yok
    Yayın
    Optimization of PERC fabrication based on loss analysis in an industrially relevant environment: First results from GUNAM photovoltaic line (GPVL)
    (PERGAMON-ELSEVIER SCIENCE LTD, 2020) Es, Firat; Semiz, Emel; Orhan, Efe; Genc, Ezgi; Kokbudak, Gamze; Baytemir, Gulsen; Turan, Rasit
    Passivated emitter and rear cell (PERC) concept with an already developed roadmap for 24% efficiency will be leading the photovoltaics industry in the upcoming years. In a few industrial pilot lines, efficiencies above 22% have already been attained. Pilot lines have important roles in bridging lab scale proven concepts with the products which are ready for mass production. Therefore, GUNAM Photovoltaic Line which is specialized on PERC concepts has been established to overcome the barriers that hinder the performance of c-Si solar cells in PERC concepts in a relevant environment. The aim of this article is to show how a loss analysis can be employed in a practical way in an industrially relevant environment. The analysis depends on the first results of the studies from 6 months ramp up period of GPVL A batch of standard PERC type solar cells with p-type base and atomic layer deposited Al2O3 rear passivation have been fabricated during the ramp up of the line. A detailed gain-loss analysis was performed to address the optical, electrical and recombination losses in order to increase the cell efficiency. (C) 2019 Elsevier Ltd. All rights reserved.