Open AccessBifacial Passivation of Organic Hole Transport Interlayer for NiO x ‐Based p‐i‐n Perovskite Solar Cells
Author(s) -
Li Zijia,
Jo Bong Hyun,
Hwang Su Jin,
Kim Tae Hak,
Somasundaram Sivaraman,
Kamaraj Eswaran,
Bang Jiwon,
Ahn Tae Kyu,
Park Sanghyuk,
Park Hui Joon
Publication year - 2019
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201802163
Subject(s) - passivation , materials science , non blocking i/o , crystallinity , perovskite (structure) , x ray photoelectron spectroscopy , photoluminescence , raman spectroscopy , chemical engineering , optoelectronics , nanotechnology , chemistry , optics , catalysis , organic chemistry , physics , composite material , layer (electronics) , engineering
Abstract Methoxy‐functionalized triphenylamine‐imidazole derivatives that can simultaneously work as hole transport materials (HTMs) and interface‐modifiers are designed for high‐performance and stable perovskite solar cells (PSCs). Satisfying the fundamental electrical and optical properties as HTMs of p‐i‐n planar PSCs, their energy levels can be further tuned by the number of methoxy units for better alignment with those of perovskite, leading to efficient hole extraction. Moreover, when they are introduced between perovskite photoabsorber and low‐temperature solution‐processed NiO x interlayer, widely featured as an inorganic HTM but known to be vulnerable to interfacial defect generation and poor contact formation with perovskite, nitrogen and oxygen atoms in those organic molecules are found to work as Lewis bases that can passivate undercoordinated ion‐induced defects in the perovskite and NiO x layers inducing carrier recombination, and the improved interfaces are also beneficial to enhance the crystallinity of perovskite. The formation of Lewis adducts is directly observed by IR, Raman, and X‐ray photoelectron spectroscopy, and improved charge extraction and reduced recombination kinetics are confirmed by time‐resolved photoluminescence and transient photovoltage experiments. Moreover, UV‐blocking ability of the organic HTMs, the ameliorated interfacial property, and the improved crystallinity of perovskite significantly enhance the stability of PSCs under constant UV illumination in air without encapsulation.