Highly efficient quasi-solid-state dye-sensitized solar cells (QS-DSSCs) are fabricated using nanocomposite gel electrolytes and applied under room light conditions (200 lx). To obtain high energy conversion efficiency in QS-DSSCs, the important components of the DSSC are systematically optimized based on their performance in liquid-state DSSCs. It shows that the liquid cell using the 3-methoxypropionitrile-based cobalt electrolyte has higher efficiency (18.91%) than the cell using the acetonitrile-based electrolyte (17.82%) under 200 lx illumination due to the higher charge recombination resistance at the photoelectrode/electrolyte interface for the 3-methoxypropionitrile system. Poly(vinylidene fluoride-co-hexafluoropropylene) is utilized as the gelator of the liquid electrolytes to prepare polymer gel electrolytes. Furthermore, to improve the performance of the QS-DSSCs, different metal oxide nanoparticles are introduced as nanofillers of the polymer gel electrolytes. It shows that the zinc oxide nanofillers have a superior performance in increasing the cell efficiency and the energy conversion efficiencies of the QS-DSSCs are higher than those of the corresponding liquid cells. By regulating the concentration of the zinc oxide nanofillers, the efficiency of the 3-methoxypropionitrile based QS-DSSC can achieve a value of 20.11% under 200 lx illumination. This QS-DSSC has a long-term stability at 35 °C.
Polymer gel electrolytes (PGEs) of cobalt redox system are prepared for dye sensitized solar cell (DSSC) applications. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is used as a gelator of an acetonitrile (ACN) liquid electrolyte containing tris(2,2'-bipyridine)cobalt(II/III) redox couple. Titanium dioxide (TiO2) and titanium carbide (TiC) nanoparticles are utilized as nanofillers (NFs) of this PGE, and the effects of the two NFs on the conductivity of the PGEs, charge-transfer resistances at the electrode/PGE interface, and the performance of the gel-state DSSCs are studied and compared. The results show that the presence of TiC NFs significantly increases the conductivity of the PGE and decreases the charge-transfer resistance at the Pt counter-electrode (CE)/PGE interface. Therefore, the gel-state DSSC utilizing TiC NFs can achieve a conversion efficiency (6.29%) comparable to its liquid counterpart (6.30%), and, furthermore, the cell efficiency can retain 94% of its initial value after a 1000 h stability test at 50 °C. On the contrary, introduction of TiO2 NFs in the PGE causes a decrease of cell performances. It shows that the presence of TiO2 NFs increases the charge-transfer resistance at the Pt CE/PGE interface, induces the charge recombination at the photoanode/PGE interface, and, furthermore, causes a dye desorption in a long-term-stability test. These results are different from those reported for the iodide redox system and are ascribed to a specific attractive interaction between TiO2 and cobalt redox ions.
Process-centered software engineering environments (PSEEs) facilitate managing software projects. According to the change of enactment environments and the increment of software development complexity, PSEE features should be enhanced. We designed a knowledge-based PSEE named KPSEE. It offers the features: (1) maximizing the degree of process parallelism, (2) enhancing process flexibility, (3) managing product consistency, (4) integrating PSEEs, (5) keeping pace with significant process change, (6) preventing technique leakage, and (7) offering project monitoring ability.
Commercial carbon black can replace expensive catalysts as a low cost highly electrocatalytic counter electrode material for Co(iii)/(ii)-mediated DSSC applications.