Electrical properties of dye-sensitized solar module with integrated parallel connections

Despite the rapid development of dye-sensitized solar cell since its early breakthrough by Graetzel in 1991, further development on the design and fabrication technique still constitutes a major challenge for this type of solar cell to reach the mass production and marketing level. Generally, the upscaling of dye-sensitized solar cell for daily utilizations necessitates the interconnection of multiple cells to form modules. In this regard, the use of screen-printing method could provide a major benefit to fabricate such structure as it is feasible for industrial and large scale manufacturing process. This contribution describes the fabrication of a 100 × 100 mm² dyesensitized solar module using semi-automatic screen-printing technique. The fabricated modules comprised of 7 individual cells made from titanium dioxide (TiO₂) nanocrystalline films, each with an active area size of 10 × 70 mm², giving an active area ratio of 70%. The cells were connected to the neighboring cells in a parallel configuration. To simulate the potential of the fabricated modules for indoor applications, the current-voltage characteristics of the module were measured under an ambient lighting with an intensity of 30 mW/cm². The parallel interconnected dye-sensitized solar module produced an open circuit voltage (V_OC) of 0.71 V with a short circuit current (I_SC) of 21.73 mA and maximum power output (P_max) of 4.19 mW. Overall, the fabricated module achieved a power conversion efficiency of 1.99%. A secondary measurement under simulated sun with an intensity of 50 mW/cm² (0.5 Sun) was also carried out to compare the performance of the modules under different environment. Under the later condition, the V_OC, I_SC, P_max, and efficiency obtained were 0.77 V, 27.64 mA, 5.47 mW, and 0.15%, respectively. Our results indicated that the dye-sensitized solar module with integrated parallel connection has a prominent advantage to be applied as an energy source for applications that requires high current input under low-light condition.