title: An efficient perovskite solar cell with symmetrical Zn(ii) phthalocyanine infiltrated buffering porous Al2O3as the hybrid interfacial hole-transporting layer.
abstract: A new Zn(ii) phthalocyanine (Pc) based low bandgap HTM is introduced for perovskite solar cells. Steady state and time-resolved photoluminescence (PL) measurements indicated an evenly matched hole extraction efficiency between sym-HTPcH and spiro-OMeTAD. On account of the low film quality and resulting high recombination, Zn(ii) Pc normally cannot work as an effective HTM. We adopted insulating Al2O3for the infiltration of sym-HTPcH to form a hybrid interfacial buffer layer, affording perovskite solar cells (PSCs) with an average PCE value of up to 12.3%, which is a significant improvement with respect to the control cell without the meso-Al2O3layer (4.21%) and is the highest value ever reported for Zn(ii) phthalocyanine based devices under AM1.5G standard conditions. A hysteresis test revealed that our device structure with the new HTM exhibited a balanced charge extraction behaviour.
authors.affiliation: Group for Molecular Engineering of Functional Materials, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, Rue de l'industrie 17, CP 440, CH-1951 Sion, Switzerland. mdkhaja.nazzeruddin@epfl.ch.
authors.forename: P
authors.initials: P
authors.lastname: Gao
authors.forename: K T
authors.initials: KT
authors.lastname: Cho
authors.forename: A
authors.initials: A
authors.lastname: Abate
authors.forename: G
authors.initials: G
authors.lastname: Grancini
authors.forename: P Y
authors.initials: PY
authors.lastname: Reddy
authors.forename: M
authors.initials: M
authors.lastname: Srivasu
authors.forename: M
authors.initials: M
authors.lastname: Adachi
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Tsuchimoto
authors.forename: M
authors.initials: M
authors.lastname: Grätzel
authors.forename: Mohammad Khaja
authors.initials: MK
authors.lastname: Nazeeruddin