Largest highly efficient 203 × 203 mm2 CH3NH3PbI3 perovskite solar modules

Abstract

We have been working on the fabrication of practical perovskite solar modules using an existing thin-film solar module patterning technology. Patterning processes were applied using laser scribing and mechanical scribing on a glass/F-doped SnO2 (FTO)/compact TiO2 (c-TiO2)/meso-TiO2/CH3NH3PbI3/2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene/Au structure. However, TiO2 remained in the FTO–Au junction at the cell connection part: this appeared to create a series resistance that degraded the performance of the module. UV laser treatment was examined for application to the cell connection part to minimize this resistance. The results showed that the resistivity of the cell connection part, which was conventionally 0.26 Ω·cm2, was reduced to 0.1 Ω·cm2 by this laser treatment. We designed the solar module based on the value of a contact resistivity of 0.1 Ω·cm2 and the current–voltage curve of a small single cell. As a result of prototyping solar cell modules (35 cells in series) with an aperture area of 354 cm2 on a 203 × 203 mm2 glass substrate, a module efficiency of 12.6% was achieved. There appears to be no serious impediment to the fabrication of the perovskite solar modules.