A new H3PW12O40 (PW12)-based interfacial layer for dye-sensitized solar cells (DSSCs) has been fabricated by the LBL method. The features of the interfacial layer were tested by IR and UV-vis spectroscopies and AFM. The cells were systemically tested by the photocurrent-voltage (J-V) curve, dark-current measurement, open-circuit voltage decay (OCVD), and monochromatic incident photon-to-photocurrent conversion efficiency (IPCE) techniques. The PW12-based interfacial layer was found to accelerate electron transfer and retard recombination, eventually leading to an efficient increase in energy conversion efficiency. The investigations indicate that the energy conversion efficiency of a (PW12/TiO2)(3)-based DSSC is significantly enhanced by 54% at 100 mW cm(-2) compared with a DSSC with no treatment and by 20% compared with a TiCl4-treatment DSSC. Polyoxometalate was first introduced into the interfacial layer in modifying the photoanode to accelerate electron transfer and retard recombination to improve DSSC efficiency in this work.