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Architecture of the Interface between the Perovskite and Hole‐Transport Layers in Perovskite Solar Cells
Author(s) -
Moriya Masahiro,
Hirotani Daisuke,
Ohta Tsuyoshi,
Ogomi Yuhei,
Shen Qing,
Ripolles Teresa S.,
Yoshino Kenji,
Toyoda Taro,
Minemoto Takashi,
Hayase Shuzi
Publication year - 2016
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201600848
Subject(s) - materials science , perovskite (structure) , thin film , mesoporous material , layer (electronics) , chemical engineering , tin oxide , spin coating , doping , optoelectronics , nanotechnology , chemistry , catalysis , organic chemistry , engineering
The interface between the perovskite (PVK, CH 3 NH 3 PbI 3 ) and hole‐transport layers in perovskite solar cells is discussed. The device architecture studied is as follows: F‐doped tin oxide (FTO)‐coated glass/compact TiO 2 /mesoporous TiO 2 /PVK/2,2′,7,7′‐tetrakis‐( N , N ‐di‐4‐methoxyphenylamino)‐9,9′‐spirobifluorene (Spiro‐MeOTAD)/Au. After a thin layer of 4,4,4‐trifluorobutylammonium iodide (TFBA) was inserted at the interface between PVK and Spiro‐MeOTAD, the photovoltaic efficiency increased from 11.6–14.5 % to 15.1–17.6 %. TFBA (10 ppm) was added in the PVK solution before coating. Owing to the low surface tension of TFBA, TFBA rose to the surface of the PVK layer spontaneously during spin‐coating to make a thin organic layer. The PVK grain boundaries also seemed to be passivated with the addition of TFBA. However, large differences in Urbach energies and valence band energy level were not observed for the PVK layer with and without the addition of TFBA. The charge recombination time constant between the PVK and the Spiro‐MeOTAD became slower (from 8.4 to 280 μsec) after 10 ppm of TFBA was added in the PVK. The experimental results using TFBA conclude that insertion of a very thin layer at the interface between PVK and Spiro‐MeOTAD is effective for suppressing charge recombination and increasing photovoltaic performances.