TCO-free dye solar cells based on Ti back contact electrode by facile printing method

Abstract

The back contact dye solar cells (BCDSCs), in which the TCO(Transparent Conductive oxide) is omitted, have a potential for use of intact low-cost general substrates such as glass, metal foil and papers. Herein, we introduce a facile manufacturing method of a Ti back contact electrode (Ti BCE) for the BCDSCs. We found that the polylinkers such as poly(butyl titanate) have a strong binding property to make Ti particles connect one with another. A porous Ti film, which consists of Ti particles of ≤ 10㎛ size connected by a small amount of polylinkers, has an excellent low sheet resistance of 10 Ω sq-1 for an efficient electron collection for DSCs. This Ti BCE can be prepared by using a facile printing method under normal ambient conditions. Conjugating the new back contact electrode technology with the traditional monolithic structure using the carbon counter electrode, we fabricated TCO-less DSCs. These four-layer structurered DSCs consist of a dye-adsorbed nanocrystalline TiO2 film on a glass substrate, a porous Ti back contact layer, a ZrO2 spacer layer and a carbon counter electrode in a layered structure. Under AM 1.5 G and 100 mWcm−2 simulated sunlight illumination, the four-layer structurered DSCs with N719 dyes and I-/I3-redox electrolytes achieved PCEs up to 5.21 %.

Keywords

• Dye solar cells
• TCO-less
• Back contact
• Printing
• Porous Ti film