Study On Photoanode Modified By Polyoxometalates Nanoparticles And Its Photovoltaic Properties

In this work,two kinds of polyoxometallate?POM?nanoparticles(PW₁₂-CDS@TiO₂ and SiW₁₂-CDS @ TiO₂)with controlled shape and structure were synthesized by micellar orientation method.Then the nanoparticles were combined with TiO₂ by the sol-gel method and calcination to remove the surfactants,finally obtaining two kinds of TiO₂ composites(PW₁₂-Cs₂SO₄ @ Ti O₂ and SiW₁₂-Cs₂SO₄ @ TiO₂)with highly dispersed and small-sized POM nanoparticles?¹ nm?.The composition and morphology of the composites were verified by scanning electron microscopy,transmission electron microscopy and X-ray photoelectron spectroscopy.The two kinds of Ti O₂ composites were then doped into the dye-sensitized?N719?solar cells?DSSCs?.And the pure POM and CDS were separately doped into the photoanode to prepare solar cells for parallel experiments.Due to the excellent electronic storage and transmission capability of POM,the pure POM photoanode has a higher performance than the blank.The efficiency of solar cells doped with CDS is also higher than that of blank,because CDS can reduce particles aggregation after sintering,which is beneficial to dye absorption.The power conversion efficiency?PCE?of the two kinds of TiO₂ composites were the highest,8.4% and 8.2%,respectively,which were 42% and 39% higher than that of the original pure TiO₂-based photoanodes?5.9%?,respectively.Due to the nanostructures and high dispersibility of POM,the separation of electron-hole becomes more rapid because of its large specific surface area,providing more active sites than pure POM,while pure POM tends to agglomerate.The electrochemical impedance spectroscopy,open circuit voltage decay curve and other tests proved this result.Finally,we put forward the working mechanism of POM in dye-sensitized solar cells according to theoretical and experimental data.