Time efficient texturization of multicrystalline silicon in the HF/HNO3 solutions and its effect on optoelectronic parameters of solar cells

In this paper the improving photovoltaic conversion efficiency of multicrystalline silicon solar cells obtained by acid texturization is presented. Different solutions from two various composition ranges of HF:HNO3:CH3COOH/H2O system were examined. The influence of the HF/HNO3 content, type of diluents and texturization process time on the basic optoelectronic parameters of multicrystalline solar cells was also studied. This research brings new experimental receipt which allows to obtain the proper surface morphology after the texturization in a very short time of 60 s. The optimal acid volume etching ratio was found to be HF:HNO3:H2O = 7:1:2. For the first time, etching lasting 1 min causes the lowering the reflectivity value below 12% and also improves the conversion efficiency by 22% in relation to the reference sample without acid texture. The inverse HF/HNO3 ratio resulted in two times higher diameter of obtained rounded pits which allowed better coverage of the front metal grid patterning over the flat surface. Moreover, the higher reflectance value was accompanied by relatively high efficiency up to 13.9%. (C) 2014 Politechnika Wroclawska. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.