title: Flame-made ultra-porous TiO2layers for perovskite solar cells.
abstract: We report methyl ammonium lead iodide (MAPbI3) solar cells with an ultra-porous TiO2electron transport layer fabricated using sequential flame aerosol and atomic layer depositions of porous and compact TiO2layers. Flame aerosol pyrolysis allows rapid deposition of nanostructured and ultra-porous TiO2layers that could be easily scaled-up for high-throughput low-cost industrial solar cell production. An efficiency of 13.7% was achieved with a flame-made nanostructured and ultra-porous TiO2electrode that was coated with a compact 2 nm TiO2layer. This demonstrates that MAPbI3solar cells with a flame-made porous TiO2layer can have a comparable efficiency to that of the control MAPbI3solar cell with the well-established spin-coated porous TiO2layer. The combination of flame aerosol and atomic layer deposition provides precise control of the TiO2porosity. Notably, the porosity of the as-deposited flame-made TiO2layers was 97% which was then fine-tuned down to 87%, 56% and 35% by varying the thickness of the subsequent compact TiO2coating step. The effects of the decrease in porosity on the device performance are discussed. It is also shown that MAPbI3easily infiltrates into the flame-made porous TiO2nanostructure thanks to their high porosity and large pore size.
authors.affiliation: Centre for Sustainable Energy Systems, Research School of Engineering, The Australian National University, Bldg. 32, Acton 2601, ACT, Australia.
authors.forename: Yahuitl Osorio
authors.initials: YO
authors.lastname: Mayon
authors.forename: The
authors.initials: T
authors.lastname: Duong
authors.forename: Noushin
authors.initials: N
authors.lastname: Nasiri
authors.forename: Thomas P
authors.initials: TP
authors.lastname: White
authors.forename: Antonio
authors.initials: A
authors.lastname: Tricoli
authors.forename: Kylie R
authors.initials: KR
authors.lastname: Catchpole