A detailed study on the working mechanism of a heteropoly acid modified TiO₂ photoanode for efficient dye-sensitized solar cells

Abstract

A novel heteropolyacid (HPA) K6SiW11O39Ni(H2O)·xH2O (SiW11Ni) modified TiO2 has been successfully synthesized and introduced into the photoanode of dye-sensitized solar cells (DSSCs). The performance of the cell with the HPA-modified photoanode (SiW11Ni/TiO2), mixed with P25 powder in the ratio of 2 : 8, is better than the cell with a pristine P25 photoanode. An increase of 31% in the photocurrent and 22% improvement in the conversion efficiency are obtained. The effect of the heteropolyacid was well studied by UV-vis spectroscopy, spectro-electrochemical spectroscopy, dark current, intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy, open-circuit voltage decay and electrochemical impedance spectroscopy. The results show that the interfacial layer modified by SiW11Ni can enhance the injection and transport of electrons, and then retard the recombination of electrons, which results in a longer electron lifetime. What's more, the introduction of SiW11Ni can simultaneously broaden the absorption in the visible region, eventually leading to an efficient increase in energy conversion efficiency.

Recent Progress on Functionalized Nanoporous Heteropoly Acids: From Synthesis to Applications

“…applied the HPA modified Titania as a photoanode for dye‐sensitized solar cells. An increase of 31 % and 22 % was obtained for photocurrent and conversion efficiency, respectively [144] . Li et al .…”

“…An increase of 31 % and 22 % was obtained for photocurrent and conversion efficiency, respectively. [144] Li et al introduced an efficient electrocatalyst using phosphomolybdic acid (PMA) catalyst for photocatalytic H 2 evolution with of 29.70 μmol/h under visible light irradiation. The PMA played a crucial role in both polymerizing the aniline (ANI) monomer and oxidizing the thiourea together with MoS 2 cocatalyst formation at a low temperature.…”

Phosphotungstic Acid Regulated Chemical Bath Deposition of Sb2S3 for High‐Efficiency Planar Heterojunction Solar Cell

“…So far, HPAs have been applied in diverse photovoltaic applications. With phosphotungstic acid modified TiO 2 photoanode for dye‐sensitized solar cells, an increase of 31 % in the photocurrent and 22 % improvement in PCE were achieved . Tungstosilicic acid was reported in the schottky barrier solar cell with Sb 2 S 3 film deposited by chemical bath as n‐type absorber material …”

Recent Progress in the Application of Polyoxometalates for Dye‐sensitized/Organic Solar Cells

“…[41] In 2015, Li and co-workers found that the introduction of WO 3 into PTA/TiO 2 films could further favor electron transfer by retarding recombination, leading to a higher photocurrent. [19,46] Meanwhile, Wang and co-workers loaded TiO 2 on the surface of the tri-pyridine-ruthenium heteropolytungstate [Ru(bipy) 3 ] 2 [SiW 12 O 40 ] 2 •C 2 H 5 OH•8H 2 O (1@TiO 2 ), which was mixed with P25 powder to serve as photoanode material in DSSCs. [42] Besides PTA, the introduction of some other Keggintype POMs can also work similarly in photoanode.…”

“…[11] The redox potential can be easily tuned by adjusting the structure and composition of POMs. [15,16] These special and superior physicochemical properties make POMs become the focus of research in many fields, such as catalyzed synthesis, [17,18] photocatalysis, [10] solar cell, [19,20] medicine, [21] electrochemistry, [22,23] geochemistry [24] and magnetism. [15,16] These special and superior physicochemical properties make POMs become the focus of research in many fields, such as catalyzed synthesis, [17,18] photocatalysis, [10] solar cell, [19,20] medicine, [21] electrochemistry, [22,23] geochemistry [24] and magnetism.…”