End-functional silicone coupling agent modified PEO/P(VDF-HFP)<i>/</i>SiO₂nanocomposite polymer electrolyte DSSC

Abstract

The end-functional silicone coupling agent (dodecyl-trimethoxysilane, DTMS for short) was used to modify the PEO/P(VDF-HFP)/SiO(2) nanocomposite polymer electrolyte (CPE) and the different amounts of DTMS modification effects were studied. The experiments showed the silicone coupling agent with hydrophobic alkyl chains (-C(12)H(25)) chemically engineered on the SiO(2) nanoparticles, and formed a Si-O-Si cross-linked network in the new nanocomposite polymer electrolyte. Proper content of DTMS modified CPE exhibited improved ionic conductivity and the connection with the photoanode and counter electrode. However, much higher content of the DTMS modification changed the conformation of the polymer network and reduced the ionic movement. Compared with the performance (3.84%) of the original DSSC, the DSSC with functional silicone coupling agent modified CPE (DTMS:SiO(2) = 2:1, mol ratio) exhibited improved J(sc) (7.94 mA cm(-2)), V(oc) (0.624 V) and optimal efficiency (5.2%) (measured at AM1.5, light intensity of 58.4 mW cm(-2)). The V(oc) of the silicone coupling agent modified polymer electrolyte DSSC is obviously improved, which is mainly due to that the hydrophobic alkyl chain end groups formed an insulating layer that retarded the electron recombination at the TiO(2) nanoporous photoanode/polymer electrolyte interface. The DTMS:SiO(2) = 2:1 modified CPE type DSSC exhibited a performance of 6.42% at a light intensity of 32.1 mW cm(-2) and 4.94% at 99.2 mW cm(-2).