Demonstration of 12 Years Outdoor Working of Highly Durable Dye-Sensitized Solar Cell Modules Employing Hydrophobic Surface Passivation and Suppression of Biased Distribution of Iodine Ions

Abstract

Dye-sensitized solar cells (DSCs) outperform conventional silicon solar cells in terms of weight and design flexibility. Therefore, besides standard rooftop installation, DSCs are suitable for new applications, including windows and walls. However, insufficient durability remains a critical issue, and outdoor working over 10 years is yet to be realized. In this study, we developed two approaches to improve the durability. The first involves hydrophobic surface passivation on the TiO 2 surfaces by adopting alkylbenzimidazole (C n H 2n+1 BI) with long alkyl chains instead of the conventional additive (N-methylbenzimidazole) used for high open-circuit voltage in an ionic liquid-based electrolyte. The additive with a suitable alkyl-chain length (N-butylbenzimidazole and N-hexylbenzimidazole) notably improved the resistance against infiltrating water. The second approach refers to the DSC module arrangement. A unique problem of largesized modules is that the I 3 − distribution often becomes biased over time, lowering the conversion efficiency. Horizontal module arrangements and/or the strip-shaped single cells in the modules solved this problem. By adopting these two approaches, we have demonstrated that the 10 cm × 11 cm-sized DSC modules have high durability to maintain 75% of their initial performance after the 12 year outdoor working test. This is the longest demonstrated lifetime for DSC modules outdoors.

A Review on Liquid Electrolyte Stability Issues for Commercialization of Dye-Sensitized Solar Cells (DSSC)

“…Another possibility is shown by Kato et al [44] who used olefin elastomer, acrylic and epoxy resin, and polyisobutylenes to seal the glass flakes. With further optimization, they were able to produce DSSCs with 75% residual efficiency after 12 years outdoors.…”

Copper-Based Aqueous Dye-Sensitized Solar Cell: Seeking a Sustainable and Long-Term Stable Device

“…In 1991, the seminal work on the well-known dye-sensitized solar cell (DSSC) by Grätzel and O’Regan was initially reported, and since then various research groups have been involved in optimizing the DSSC’s efficiency and its outdoor durability . This includes the development of new photoanodes, , counter electrodes, , dyes, ,, and electrolyte media. − Notably, researchers have achieved high-efficiency DSSCs with power conversion efficiency (PCE %) values ranging between 12 and 15% under 1 Sun illumination using different redox mediators such as I – /I 3 – , thiolate/disulfide, cobalt, and copper complexes. − Furthermore, recent studies have demonstrated the superior performance of DSSCs operating under ambient light conditions compared to other solar devices. ,− Remarkably, these devices exhibited high PCEs with various mediators. For instance, using I – /I 3 – mediators, PCEs have surpassed 30% .…”

Push-pull photochromic dyes for semi-transparent solar cells with light-adjustable optical properties and high color-rendering index

“…18 Second, when non-volatile electrolytes are used, their stability is greatly improved and lifetimes in excess of 10 years have already been demonstrated in accelerated ageing tests, 19 and reaching 12 years in real-world. 20 Thirdly, these solar cells and the corresponding modules are fully customizable; 2,21,22 their shape, colour, and transparency can be adjusted during the manufacturing process. 23 Finally, their energy payback time 24 and carbon footprint are estimated to be lower than for silicon-based solar cells.…”