Efficiency enhancement of organic solar cells by inserting PbS quantum dots film as the infrared absorption layer

Organic materials show great potentials in high-efficiency organic solar cells, however, few organic materials can efficiently utilize the near infrared light due to their relative large band-gap. Here, we demonstrate quantum dots-based hybrid solar cells by inserting PbS nanocomposite film as the infrared absorption layer, resulting in a significant enhancement in short-circuit current. After appropriate ligands exchange, the device with PbS absorption layer showed an improved power conversion efficiency (PCE) of 3.08% under AM 1.5 solar illumination, amounting to 91% enhancement over that of the pure organic multilayer structure solar cell indium-tin oxide (ITO)/poly(3-hexylthiophene) (P3HT)/ polymer-[6,6]-phenyl-C₆₁-butyric acidmethyl ester (PCBM)/Ca/Al. Therefore, this approach can be applied to a wide range of quantum dots and polymer hybrids for its solution-processing, thereby offering a general scheme to improve the efficiency of organic–inorganic hybrid solar cells and it provides a promising way to make high-efficiency solar cells.