Improvement of photocurrent generation of Ag2S sensitized solar cell through co-sensitization with CdS

In this study, photovoltaic application of Ag2S-CdS heterostructure is reported. The photovoltaic cell generated considerably high photocurrent density (J(sc)) of 27.6 mA/cm(2), which is over two times larger than that of the Ag2S quantum dot sensitized solar cell (QDSSC) of 11.3 mA/cm(2). This improvement is due to the cascade-shaped band structure alignment of ZnO/CdS/Ag2S and to the excellent role of CdS as a buffer layer for relieving lattice mismatch. The power conversion efficiency of the CdS/Ag2S QDSSC, which was attributed to the superior J(sc), was 2.4%, twice as high as the 1.2% efficiency of the Ag2S QDSSC and the CdS QDSSC. (C) 2013 AIP Publishing LLC.