## 1 Introduction  
In the context of climate change and severe problems regarding fossil fuel and nuclear waste, harvesting of solar energy is a potential alternative to fulfil future energy needs as it is a rapidly growing renewable energy technology [1]. One challenge concerning conventional semiconductor-based photovoltaics are their relatively high production costs due to the need of a cleanroom and uncommon elements like indium [2, 3]. Therefore dye-sensitized solar cells (DSSCs), fabricated in a simple process without a cleanroom and from inexpensive materials, offer a good alternative [1, 4, 5]. The environmental friendliness of DSSCs can be further improved by using non-toxic materials, such as widely available natural dyes [4, 5]. In addition to improving the conversion efficiency, which is significantly lower when using natural dyes as absorbers compared to conventional toxic ones, it is also generally crucial to improve the long-term stability, which is commonly deteriorated by leakage of liquid electrolyte [4, 5, 6]. Generally, the electrolyte closes the electric cycle of DSSCs via iodine-triiodide as redox shuttle transferring an incoming electron from the counter electrode and regenerating the oxidized dye with it [6, 7]. The leakage problem is particularly pronounced in textile-based DSSCs, which are promising in terms of textile architecture and wearable electronics, due to the open-pore structure of the textile and the inherent sealing inability [6, 8]. In order to hinder solvent evaporation or leakage of the electrolyte and to enhance the long-term stability, gelling the electrolyte with polymers is feasible [7, 9, 10]. The solvent of a gel polymer electrolyte (GPE) obtained in this way has classically a concentration above 50 wt% and is trapped by the added polymer, which forms a three-dimensional network wherein ion movement in the remaining liquid phase still occurs [11; 12; 13]. With regard to the used polymer, it is commonly distinguished between inert ones, where ions move only in the trapped salt solution, and coordinating polymer frameworks, in which the cation is dissolved by the polymer and thus the solid phase contributes also to the ion transport [12]. Examples regarding polymers for inert GPEs are poly (methyl methacrylate) (PMMA), polyacrylamide(PAN) or poly (vinylidene fluoride) (PVDF) [9; 12]. Predominantly, GPEs for DSSCs apply poly (ethylene oxide) (PEO), which is a coordinating polymer [7; 9]. The crystallinity of PEO is known to hinder ionic movement, where blending with other polymers can be conducted to reduce the crystallinity by imposing some disorder within the structure [12; 14]. Due to our motivation to produce non-toxic DSSCs, most frequently used toxic solvents like acetonitrile are out of the question [7]. Therefore, an important criterion for the polymers used in this paper is their solvability in the low-toxic solvent dimethyl sulfoxide (DMSO), which proved to be suitable regarding GPEs of environmentally friendly DSSCs [15]. PAN is very well soluble in DMSO [16] and often used as a basis for GPE DSSCs [17; 18; 19]. Like mentioned above, PAN provides an inert ion transport and offers ionic conductivity higher than PEO [19]. Furthermore, as mentioned by [PERSON] et al. [17], PAN can be used for gelling liquid electrolytes and consequently should provide a suitable polymer matrix for a long-term stable GPE. Another polymer used in an electrolyte blend with PMMA for batteries is acrylonitrile-butadiene-styrene (ABS), where it was inserted to improve the mechanical strength [20; 21]. It should be mentioned that it is unfortunately not possible to dissolve PMMA in DMSO, so we do not use this polymer and instead mixed ABS with PEO as an alternative. Additionally, to the best of our knowledge, ABS has not previously been used as a polymer regarding GPEs of DSSCs. As a further polymer, the synthetically produced polyvinyl alcohol (PVA) is used, which is considered non-toxic and well dissolvable in DMSO [22].