Improving the efficiency of inverted polymer solar cells by introducing inorganic dopants

Cadmium selenide (CdSe) quantum dots (QDs) utilized as additives have been incorporated intopolymer solar cells (PSCs) composed of poly[N-9 ''-hepta-decanyl-2,7-carbazolealt-5,5-(4',7'-di-2-thienyl-2',1',3'-ben-zothiadiazole)] (PCDTBT) and fullerene derivative [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM). The maximum power conversion efficiency (PCE) of 6.94% has been achieved, corresponding to 33% enhancement compared with the control devices. The introduction of CdSe QDs allows not only the improvement of charge transport properties but also tuning of the energy levels, which leads to a higher short circuit current (J(SC)), fill factor (FF), and open-circuit voltage (V-OC).