Solvent and concentration optimization of Nano-ZnO inks and their application in perovskite solar cells
Lu H., Zhang LP., Luo Q., Zhang DY., Ma CQ., Hao J., Cui Z.
© 2016, Science Press. All right reserved. ZnO nanoparticle has been used as cathode buffer layer (CBL) in organo-lead halide perovskite (PVSK) solar cells to improve device stability against oxygen and moisture. For solution processing procedure, solvents for dissolving ZnO has to be carefully optimized, since solvent penetration during the CBL deposition might cause the decomposition of the PVSK film. Aiming at the development of nano-ZnO inks for using in PVSK solar cells, the current work systematically investigate the dispersibility of nano-ZnO in various polar solvents, including acetone, methanol, ethanol, isopropanol, n-butanol, and a mixture solvent of methanol:n-buthanol (MeOH:n-BuOH, 1:1, v/v), and the influence of such solvent on the UV-Vis absorption and crystalline properties of the underlying PVSK/PCBM film. PVSK solar cells with a device structure of ITO/PEDOT:PSS/PSS/PVSK/PCBM/ZnO/Al were then fabricated and tested. The optimized nano-ZnO ink is found to be MeOH:n-BuOH mixture solvent based (1:1, v/v) with a concentration of 10 mg·mL-1. The current work provides an important guideline for developing CBL inks for PVSK solar cells.