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In this paper, a novel kind of functional NH2-rich silica nanoparticle (A-SiO2) as an electrolyte additive is reported, which is employed to assemble high-efficiency quasi-solid-state dye-sensitized solar cells (DSCs) and quantum dot sensitized solar cells (QDSCs), while the additional solidifying character of A-SiO2 makes it superior to the common additives. It is found that the A-SiO2 nanoparticle as an additive for ionic-liquid electrolyte can significantly improve the photovoltaic performance of quasi-solid-state DSCs, especially the open-circuit photovoltage (Voc) and fill factor (FF) through (1) negatively shifting the TiO2 conduction band (CB) edge, (2) effectively facilitating the ions transport and (3) remarkably inhibiting the charge recombination. Notably, DSC fabricated using the A-SiO2 based ionic-liquid gel electrolytes achieves a power conversion efficiency (PCE) of 7.30% under 1 sun illumination (AM 1.5 G, 100 mW cm−2), which is higher than that of DSC with the ionic-liquid electrolyte employing N-methylbenzimidazole (NMBI) and Guanidinium thiocyanate (GuNCS) as additives (PCE = 6.23%). Moreover, the A-SiO2 additive is of the universality in organic electrolytes for DSCs and polysulfide electrolytes for QDSCs. The PCE of CdS/CdSe co-sensitized QDSCs using A-SiO2 additives is improved by 34.9% due to the enhancement of short-circuit current density (Jsc) and Voc, resulting in a champion PCE of 7.11%, which is one of the best results for CdS/CdSe co-sensitized QDSCs.

As one of the main components, inorganic nanofillers have important effect on the performance of “soggy sand” electrolytes. In this study, we first incorporate AlOOH nanofibers into ionic liquid electrolytes to enhance the mechanical property and ionic conductivity of the electrolytes. The AlOOH nanofiber has high aspect ratio coupled with favorable surface properties such as rich hydroxyl groups, which facilitate to interact with cations of ionic liquids, promote salt dissociation, and form stable gels by self-assembly. In addition, the nanofiber fillers with high aspect ratio can form ion-conducting network channels and longer-range continuous ion transport pathways. The enhancing ionic conductivity of “soggy sand” electrolytes and performance of DSSCs due to addition of AlOOH nanofibers are systematically investigated by various techniques. The highest ionic conductivity of “soggy sand” electrolyte reaches 3.69 mS cm−1 at room temperature, which is 4 times than that of the pristine ionic liquid electrolyte. The effective solidification by AlOOH nanofibers provides substantial improvements in stability. The “soggy sand” electrolytes with AlOOH nanofibers can significantly improve the performance of devices by accelerating charge transport, reducing electron recombination and increasing charge collection efficiency. The DSSC with AlOOH nanofibers in electrolyte yields a high efficiency up to 7.89%, which is 29% higher than that of the reference device.

Introducing oligo-organosiloxane grafting oligo(ethylene oxide-co-propylene oxide) dimethylamine (OEA) into PEO polymer electrolyte, at low degree loading (OEA:PEO = 0.05:0.95, w/w), improved remarkably the performance of solid state dye sensitized solar cell (SDSCs), resulting in an overall conversion efficiency of 3.06% under AM 1.5 illumination of 100 mW cm −2 . The addition of OEA into PEO electrolyte not only significantly increased ionic conductivity and apparent diffusion coefficients of I 3 − in the electrolyte, but also promoted interfacial contacts of electrolyte/TiO 2 and interfacial property of electrolyte/counter electrode. The quaternized OEA (OEI) was also introduced to the PEO electrolyte. XRD patterns revealed that the addition of small amount of OEA or OEI did not reduce the crystallinity of PEO much while its crystal orientation was preferentially directed. Besides, IR measurements illustrated the existence of hydrogen bond between the dimethylamine groups on OEA and the hydroxyl groups on PEO. The crystal orientation and also the hydrogen bond were deduced benefited the electrolytic properties and further the device photovoltaic performances.

A novel thixotropic composite electrolyte was fabricated by using the amine group-functionalized silica nanoparticles as the gelator of an ionic liquid-based electrolyte for dye-sensitized solar cells. The SEM image of electrode deposited with electrolyte confirms that the high viscous gel electrolyte has a good contact with TiO 2 electrode ascribed to the thixotropic property of the electrolyte. Based on the thixotropic and ionic liquid based-electrolyte containing the amine group-functionalized silica particles, the cells show better performance owing to the increased open-circuit voltage than that of the liquid device, yield a high energy conversion efficiency of 6.69% under AM 1.5 illumination at 100 mV cm −2 when the content of the amine group-functionalized silica is 15 wt.% and exhibit a long-term stability without sealing.

A kind of polymer–metal complex gel electrolyte is successfully prepared and is used in dye-sensitized solar cells. Raman and X-ray photoelectron spectroscopy confirm the structure of this complex and is found that the metal ion reacts with nitrogen in the polymer. This novel electrolyte shows apparent diffusion coefficient of iodide of 8.37 × 10−7 cm2 s−1 and the energy conversion efficiency of 6.10% when the amount of ZnI2 is 0.04 M. By studying the dissociation active energy of the inorganic salt in electrolytes, we find that the metal salts can dissociate more easily after reacting with polymer and as a result can provide extra free iodide ion. The cell maintains ca. 93% of its initial efficiency after 20 d without further sealing, which shows good long-time stability.

Poly(vinylpyridine- co -ethylene glycol methyl ether methacrylate) (P(VP- co -MEOMA)) and α,ω-diiodo poly(ethylene oxide- co -propylene oxide) (I[(EO) 0.8 - co -(PO) 0.2 ] y I) were synthesized and used as chemically cross-linked precursors of the electrolyte for dye-sensitized solar cells. Meanwhile, α-iodo poly(ethylene oxide- co -propylene oxide) methyl ether (CH 3 O[(EO) 0.8 - co -(PO) 0.2 ] x I) was synthesized and added into the electrolyte as an internal plasticizer. Novel polymer electrolyte resulting from chemically cross-linked precursors was obtained by the quaterisation at 90 °C for 30 min. The characteristics for this kind of electrolyte were investigated by means of ionic conductivity, thermogravimetric and photocurrent–voltage. The ambient ionic conductivity was significantly enhanced to 2.3 × 10 −4 S cm −1 after introducing plasticizer, modified-ionic liquid. The weight loss of the solid state electrolyte at 200 °C was 1.8%, and its decomposition temperature was 287 °C. Solid state dye-sensitized solar cell based on chemically cross-linked electrolyte presented an overall conversion efficiency of 2.35% under AM1.5 irradiation (100 mW cm −2 ). The as-fabricated device maintained 88% of its initial performance at room temperature even without sealing for 30 days, showing a good stability.

A poly(ether urethane) (PEUR)/poly(ethylene oxide) (PEO)/SiO 2 based nanocomposite polymer is prepared and employed in the construction of high efficiency all-solid-state dye-sensitized nanocrystalline solar cells. The introduction of low-molecular weight PEUR prepolymer into PEO electrolyte has greatly enhance the electrolyte performance by both improving the interfacial contact properties of electrode/electrolyte and decreasing the PEO crystallization, which were confirmed by XRD and SEM characteristics. The effects of polymer composition, nano SiO 2 content on the ionic conductivity and I 3 − ions diffusion of polymer-blend electrolyte are investigated. The optimized composition yields an energy conversion efficiency of 3.71% under irradiation by white light (100 mW cm −2 ).

Two latent chemical cross-linked precursors: (1) oligo-organophosphazene with propionitrile and iodo-(ethylene oxide- co -propylene oxide) and (2) oligo-organosiloxane grafting oligo-ethylene oxide and propylene oxide dimethylamine are synthesized to form all-solid-state polymer electrolyte for dye-sensitized solar cells employing in situ quaterization reaction. This novel electrolyte shows about 6.79 × 10 −7 cm 2 s −1 of the apparent diffusion coefficient of triiodide. The disintegrating temperature of 181 °C demonstrates good thermal stability of the solid-state electrolyte. Proper amount of 7 nm SiO 2 modified with 3-triethoxysilylpropyl oligo(oxyethylene- co -oxypropylene) monomethyl urethane is added to the electrolyte and the photocurrent conversion efficiency reaches 2.66% compared with that of 1.81% with no additive.

Poly(vinylpyridine-co-acrylonitrile) (P(VP-co-AN)) was used to form polymer electrolytes for dye-sensitized solar cells (DSSCs). The effects of P(VP-co-AN) on the photovoltaic performances of DSSCs have been investigated with nonaqueous electrolytes containing alkali-iodide and iodine. It was found that the effect of P(VP-co-AN) on Voc closely related to its amount in the electrolyte. Lower amount of P(VP-co-AN) was benefit for the construction of a solar cell containing P(VP-co-AN) with higher energy conversion efficiency. Chemically crosslinking solidification with backbone polymer P(VP-co-AN) amount of 3% fabricated quasi–solid DSSCs with 10% increased conversion efficiencies with relative to that of the initial liquid DSSCs.

A novel network polymer electrolyte based on the polymethylsiloxane system has been designed and synthesized. In the network polymers, different numbers of PEO chains with various molecular weights were introduced onto the networks as immobile internal plasticizer through a hydrosilylation reaction. The presence of internal plasticizers pendant on the network backbones can lower the glass transition temperatures (Tg) of the electrolytes, make the lithium salt easily dissolved and accelerate the migration of free lithium ions migration. The ambient ionic conductivity (σRT) was significantly enhanced compared with that of network polymer electrolytes without internal plasticizers. The optimum ionic conductivity was 10−4.1 S cm−1 at room temperature and 10−3.0 S cm−1 at 80°C.

A class of ambient temperature solid electrolyte based on an `inorganic salt–organic salt' hybrid system is reported. The hybrid system was investigated by the measurement of ionic conductivities and the interaction between the ions of the hybrid system was studied by Raman spectroscopy. The organic salt in the hybrid system not only promoted the dissociation of the lithium salt, but also provided the hybrid system with an improved rubbery property.

The electrochemical hydrating/dehydrating behavior of MmNi5-type alloy electrodes in an alkaline solution was investigated with cyclic voltammetry, scanning electron microscopy and X-ray photoelectron spectroscopy analysis. At an Mm(Ni3.8Co0.5Al0.4Mn0.3)5 powder microelectrode, a hydrogen absorption peak was observed at more negative potential than that of the water electroreduction and hydrogen adsorption peak in its cyclic voltammograms. In addition, the electrochemical mechanism of the hydrogen absorption and desorption at the hydride electrodes in the alkaline solution is discussed.