title: Effect of Energy Alignment, Electron Mobility, and Film Morphology of Perylene Diimide Based Polymers as Electron Transport Layer on the Performance of Perovskite Solar Cells.
abstract: For organic-inorganic perovskite solar cells (PerSCs), the electron transport layer (ETL) plays a crucial role in efficient electron extraction and transport for high performance PerSCs. Fullerene and its derivatives are commonly used as ETL for p-i-n structured PerSCs. However, these spherical small molecules are easy to aggregate with high annealing temperature and thus induce morphology stability problems. N-type conjugated polymers are promising candidates to overcome these problems due to the tunable energy levels, controllable aggregation behaviors, and good film formation abilities. Herein, a series of perylene diimide (PDI) based polymers (PX-PDIs), which contain different copolymeried units (X), including vinylene (V), thiophene (T), selenophene (Se), dibenzosilole (DBS), and cyclopentadithiophene (CPDT), are introduced as ETL for p-i-n structured PerSCs. The effect of energy alignment, electron mobility, and film morphology of these ETLs on the photovoltaic performance of the PerSCs are fully investigated. Among the PX-PDIs, PV-PDI demonstrates the deeper LUMO energy level, the highly delocalized LUMO electron density, and a better planar structure, making it the best electron transport material for PerSCs. The planar heterojunction PerSC with PV-PDI as ETL achieves a power conversion efficiency (PCE) of 10.14%, among the best values for non-fullerene based PerSCs.
authors.affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, Beijing Key Laboratory of Novel Thin Film Solar Cells, North China Electric Power University , Beijing 102206, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, Beijing Key Laboratory of Novel Thin Film Solar Cells, North China Electric Power University , Beijing 102206, China.
authors.forename: Yingxue
authors.initials: Y
authors.lastname: Xu
authors.affiliation: CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology , Beijing 100190, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, Beijing Key Laboratory of Novel Thin Film Solar Cells, North China Electric Power University , Beijing 102206, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology , Beijing 100190, China.
authors.forename: Erjun
authors.identifier: http://orcid.org/0000-0003-1182-311X
authors.initials: E
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, Beijing Key Laboratory of Novel Thin Film Solar Cells, North China Electric Power University , Beijing 102206, China.
authors.forename: Fuzhi
authors.initials: F
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, Beijing Key Laboratory of Novel Thin Film Solar Cells, North China Electric Power University , Beijing 102206, China.
authors.forename: Yiming
authors.initials: Y
authors.lastname: Bai
authors.affiliation: NAAM Research Group, Faculty of Science, King Abdulaziz University , Jeddah 21589, Saudi Arabia.
authors.forename: Tasawar
authors.initials: T
authors.lastname: Hayat
authors.affiliation: NAAM Research Group, Faculty of Science, King Abdulaziz University , Jeddah 21589, Saudi Arabia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Alsaedi
authors.affiliation: State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, Beijing Key Laboratory of Novel Thin Film Solar Cells, North China Electric Power University , Beijing 102206, China.
authors.forename: Zhan'ao
authors.identifier: http://orcid.org/0000-0003-2700-4725
authors.initials: Z
authors.lastname: Tan
keywords: electron mobility; energy alignment; film morphology; perovskite solar cell; perylene diimide