Performance of ZnO-Nb₂O₅ core/shell and aluminium doped ZnO electron transporting layer with CdS/CdSe quantum dot-sensitized solar cells

In the present investigation, solar cells have been fabricated using Cds/CdSe quantum dots sensitized ZnO photoanode for solar cell application. Photocurrent-voltage analysis and electrochemical impedance spectroscopy (EIS) measurements have been performed to investigate the electron transport and recombination of charge carriers in quantum dot-sensitized solar cells (QDSSCs) based on ZnO photoanodes. This dynamic study reveals that the CdS/CdSe sensitized aluminium (Al) doped ZnO NPs photoanode solar cell performs ultrafast electron transport and high charge collection efficiency (80 %). As a consequence, a power conversion efficiency as high as 5.32 % (J_SC = 12.86 mA/cm², VOC = 600 mV, FF = 69 %) for aluminium doped ZnO NPs/CdS/CdSe photoelectrode based QDSSC is observed under one sun AM 1.5 G illumination (100 mW cm^-2). This result highlights the necessity of treating QD-sensitized solar cells from another perspective than dye sensitized solar cells, considering the fundamental differences in their behavior. (author)