Dye-sensitized solar tubes: A new solar cell design for efficient current collection and improved cell sealing

A dye-sensitized solar cell (DSSC) fabricated inside a glass tube to form a dye-sensitized solar tube (DSST) is presented. We developed the synthesis of Fluorine-doped Tin oxide (FTO) with a high optical transmittance and low sheet resistance, which was deposited inside a glass tube by spray pyrolysis. The FTO was covered with a mesoporous TiO2 film using electrophoretic deposition (EPD). Subsequently the tube was sintered, sensitized with a Ru-dye (N3) and immersed into redox electrolyte while a Pt-coated rod closed the electrical circuit. Sealing of DSSCs is still a major problem. The new design reduces significantly the area that requires sealing compared to conventional flat cells, moreover sealing of a tube is significantly simpler than two flat plates. A huge advantage of the tube design is the possibility to incorporate a current collector without blocking direct sunlight from entering the cell. Panels consisting of DSSTs allow air flow in between the tubes, thus decreasing the wind resistivity while the cylindrical shape of the DSST can be used to collect diffuse light more effectively. Initial results on a prototype show a light to electric power conversion efficiency of 2.8%, demonstrating the feasibility of the new tube concept.