title: Compact layer free perovskite solar cells with 13.5% efficiency.
abstract: The recent breakthrough of organometal halide perovskites as the light harvesting layer in photovoltaic devices has led to power conversion efficiencies of over 16%. To date, most perovskite solar cells have adopted a structure in which the perovskite light absorber is placed between carrier-selective electron- and hole-transport layers (ETLs and HTLs). Here we report a new type of compact layer free bilayer perovskite solar cell and conclusively demonstrate that the ETL is not a prerequisite for obtaining excellent device efficiencies. We obtained power conversion efficiencies of up to 11.6% and 13.5% when using poly(3-hexylthiophene) and 2,2',7,7'-tetrakis(N,N-di(4-methoxyphenyl)amino)-9,9'-spirobifluorene, respectively, as the hole-transport material. This performance is very comparable to that obtained with the use of a ZnO ETL. Impedance spectroscopy suggests that while eliminating the ZnO leads to an increase in contact resistance, this is offset by a substantial decrease in surface recombination.
authors.affiliation: Department of Chemistry, University of Saskatchewan , 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.
authors.forename: Dianyi
authors.initials: D
authors.lastname: Liu
authors.forename: Jinli
authors.initials: J
authors.lastname: Yang
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Kelly
mesh_terms: D011211:Electric Power Supplies; D004583:Electrons; D012993:Solar Energy; D013499:Surface Properties