Effect of thickness and Se distribution of Sb2S3-ySey thin films to solar cell efficiency

In this work, Sb2S3-ySey thin films are prepared using the hydrothermal growth solution of antimony potassium tartrate, Na2S2O3, and selenourea, and the solar cells with the architecture of FTO/CdS/Sb2S3-ySey/spiro-OMeTAD/Au are fabricated. The influence of the CdS/FTO substrate position on top and bottom and the growth solution volumes of 40 mL and 20 mL on the properties of Sb2S3-ySey thin films and the photovoltaic performance of the corresponding solar cells is systematically investigated. The results reveal that the CdS/FTO substrate position and the growth solution volume strongly influence the thickness, homogeneous extent of the Se distribution, and oriented growth along the (221) crystal plane for Sb2S3-ySey thin films. Due to the thickness increase, the hydrothermal growth of Sb2S3-ySey thin films is dominated by Nanoparticle Formation-Adsorption Pathway. The power conversion efficiency (PCE) of Sb2S3-ySey solar cells is 8.14% for top and 40 mL, 8.23% for bottom and 40 mL, and 8.47% for bottom and 20 mL. When poly(3-hexylthiophene) (P3HT) and tetrakis(methylthio)tetrathiafulvalene (TMT-TTF) are introduced into spiro-OMeTAD, the PCE of Sb2S3-ySey solar cells can increase to 8.83% with spiro-OMeTAD:P3HT and 9.02% with spiro-OMeTAD:TMT-TTF.