Dye-sensitized solar cells (DSSCs) have been intensely researched for more than two decades. Electrolyte formulations are one of the bottlenecks to their successful commercialization, since these result in trade-offs between the photovoltaic performance and long-term performance stability. The corrosive nature of the redox shuttles in the electrolytes is an additional limitation for industrial-scale production of DSSCs, especially with low cost metallic electrodes. Numerous electrolyte formulations have been developed and tested in various DSSC configurations to address the aforementioned challenges. Here, we comprehensively review the progress on the development and application of electrolytes for DSSCs. We particularly focus on the improvements that have been made in different types of electrolytes, which result in enhanced photovoltaic performance and long-term device stability of DSSCs. Several recently introduced electrolyte materials are reviewed, and the role of electrolytes in different DSSC device designs is critically assessed. To sum up, we provide an overview of recent trends in research on electrolytes for DSSCs and highlight the advantages and limitations of recently reported novel electrolyte compositions for producing low-cost and industrially scalable solar cell technology.

Here we report printed single-walled carbon nanotubes (SWCNT) as a promising catalyst material for copper redox shuttles based electrolyte in dye-sensitized solar cells (DSSC). The SWCNT layers, which were printed at low temperature could serve as an alternative catalyst material since they outperformed the traditional thermally platinized CEs by exhibiting very low charge transfer resistance (∼2.1–2.9 Ω cm ² ) in both complete DSSCs as well as in a symmetrical CE–CE cells. The superior catalytic activity of printed SWCNT-CEs contributed to better photovoltaic performance and resulted in a higher solar-to-electrical conversion efficiency (7.0% ± 0.4%) than traditional Pt-CE based DSSCs (6.2% ± 0.4%) in full sunlight conditions. The devices fabricated with printed SWCNTs catalyst counter electrodes also exhibited impressive open circuit voltage that almost approached 1 Volt. The champion DSSC with SWCNT CE gave a 7.5% conversion efficiency under full sun illumination and 8.3% under half sun illumination. These two efficiency values are the highest ever-reported efficiencies for SWCNT-based CEs combined with a Cu-based electrolyte in DSSCs. These results could provide a pathway for efficient DSSC-based devices, which can be integrated in futuristic consumer applications for efficiently working under both full sun light and low light intensities.

Luminescence-based oxygen sensing is a widely used tool in cell culture applications. In a typical configuration, the luminescent oxygen indicators are embedded in a solid, oxygen-permeable matrix in contact with the culture medium. However, in sensitive cell cultures even minimal leaching of the potentially cytotoxic indicators can become an issue. One way to prevent the leaching is to immobilize the indicators covalently into the supporting matrix. In this paper, we report on a method where platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorphenyl)-porphyrin (PtTFPP) oxygen indicators are covalently immobilized into a polymer matrix consisting of polystyrene and poly(pentafluorostyrene). We study how the covalent immobilization influences the sensing material’s cytotoxicity to human induced pluripotent stem cell-derived (hiPSC-derived) neurons and cardiomyocytes (CMs) through 7–13 days culturing experiments and various viability analyses. Furthermore, we study the effect of the covalent immobilization on the indicator leaching and the oxygen sensing properties of the material. In addition, we demonstrate the use of the covalently linked oxygen sensing material in real time oxygen tension monitoring in functional hypoxia studies of the hiPSC-derived CMs. The results show that the covalently immobilized indicators substantially reduce indicator leaching and the cytotoxicity of the oxygen sensing material, while the influence on the oxygen sensing properties remains small or nonexistent.