title: Poly(4-Vinylpyridine)-Based Interfacial Passivation to Enhance Voltage and Moisture Stability of Lead Halide Perovskite Solar Cells.
abstract: It is well known that the surface trap states and electronic disorders in the solution-processed CH3NH3PbI3perovskite film affect the solar cell performance significantly and moisture sensitivity of photoactive perovskite material limits its practical applications. Herein, we show the surface modification of a perovskite film with a solution-processable hydrophobic polymer (poly(4-vinylpyridine), PVP), which passivates the undercoordinated lead (Pb) atoms (on the surface of perovskite) by its pyridine Lewis base side chains and thereby eliminates surface-trap states and non-radiative recombination. Moreover, it acts as an electron barrier between the perovskite and hole-transport layer (HTL) to reduce interfacial charge recombination, which led to improvement in open-circuit voltage (Voc) by 120 to 160 mV whereas the standard cell fabricated in same conditions showed Vocas low as 0.9 V owing to dominating interfacial recombination processes. Consequently, the power conversion efficiency (PCE) increased by 3 to 5 % in the polymer-modified devices (PCE=15 %) with Vocmore than 1.05 V and hysteresis-less J-V curves. Advantageously, hydrophobicity of the polymer chain was found to protect the perovskite surface from moisture and improved stability of the non-encapsulated cells, which retained their device performance up to 30 days of exposure to open atmosphere (50 % humidity).
authors.affiliation: Graduate School of Engineering, Toin University of Yokohama, 1614 Kuroganecho, Aoba, Yokohama, 225-8503, Japan.
authors.forename: Bhumika
authors.initials: B
authors.lastname: Chaudhary
authors.affiliation: Graduate School of Engineering, Toin University of Yokohama, 1614 Kuroganecho, Aoba, Yokohama, 225-8503, Japan.
authors.forename: Ashish
authors.initials: A
authors.lastname: Kulkarni
authors.affiliation: Graduate School of Engineering, Toin University of Yokohama, 1614 Kuroganecho, Aoba, Yokohama, 225-8503, Japan.
authors.forename: Ajay Kumar
authors.initials: AK
authors.lastname: Jena
authors.affiliation: Graduate School of Engineering, Toin University of Yokohama, 1614 Kuroganecho, Aoba, Yokohama, 225-8503, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Ikegami
authors.affiliation: Department of Physics, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Udagawa
authors.affiliation: Department of Physics, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kunugita
authors.affiliation: Department of Physics, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo, 102-8554, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ema
authors.affiliation: Graduate School of Engineering, Toin University of Yokohama, 1614 Kuroganecho, Aoba, Yokohama, 225-8503, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Miyasaka
mesh_terms: D017610:Calcium Compounds; D011211:Electric Power Supplies; D057927:Hydrophobic and Hydrophilic Interactions; D007854:Lead; D010087:Oxides; D011145:Polyvinyls / Q000737:chemistry*; D011725:Pyridines; D012993:Solar Energy; D013499:Surface Properties; D014025:Titanium
chemical_list: D017610:Calcium Compounds; D010087:Oxides; D011145:Polyvinyls; D011725:Pyridines; C059910:perovskite; C019535:poly(4-vinylpyridine); D007854:Lead; D014025:Titanium; C023666:pyridine
keywords: hole-transport layer; lead halides; lewis base; perovskite solar cells; poly(4-vinylpyridine)