H. Lu, et al, J. Mater. Chem. A 2015. 3. 16445

Identifying the optimum thickness ofelectron transport layers for highly efficient perovskite planar solar cells

J. Mater. Chem. A 2015. 3. 16445

H. Lu, Y. Ma, B. Gu, W. Tian*, L. Li*

The fabrication of pinhole-free and compact electrontransportlayers is crucial for achieving high power conversion efficiency ofperovskitesolarcells. In this work, we report efficientperovskitesolarcells using ultrathin TiO2 films (5-20 nm) as high-quality electrontransportlayers deposited by the atomic layer deposition technique. The as-prepared solarcells on FTO substrates show a high efficiency of 13.6%, employing theoptimum 10 nm thick TiO2 layer. Furthermore, the flexible cells on PET substrates exhibit an efficiency of 7.2% with low-temperature-processed TiO2 layers at 80 degrees C. The effects oflayer thicknesses on the cell performance are investigated to reveal the mechanism of high-performance, which is mainly attributed to high transmittance, low leakage current, and low charge transfer resistance and recombination rate. Our major findings are expected to provide a guide to design ultrathin compactelectrontransportlayersforefficientperovskitesolarcells.