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Monolayer Hexagonal Boron Nitride: An Efficient Electron Blocking Layer in Organic Photovoltaics
Author(s) -
Tavakoli Mohammad Mahdi,
Park JiHoon,
Mwaura Jeremiah,
Saravanapavanantham Mayuran,
Bulović Vladimir,
Kong Jing
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202101238
Subject(s) - materials science , monolayer , pedot:pss , organic solar cell , molybdenum disulfide , chemical vapor deposition , molybdenum trioxide , optoelectronics , band gap , nanotechnology , energy conversion efficiency , layer (electronics) , molybdenum , composite material , polymer , metallurgy
In this study, monolayer hexagonal boron nitride (h‐BN) grown via chemical vapor deposition (CVD) as an effective electron blocking layer (EBL) for the organic photovoltaics (OPVs) is proposed. Unexpectedly, it is found that h‐BN can replace the commonly used hole transport layers (HTLs), i.e., molybdenum trioxide (MoO 3 ) and poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) in an inverted device architecture. Here, a wet‐transfer technique is employed and a single layer of h‐BN on top of the PV2000:PC 60 BM blend is successfully placed. Analysis of the bandgap diagram shows that the monolayer h‐BN makes smaller barrier for holes but significantly larger barrier for electrons. This makes the h‐BN effective in blocking electrons while creating a possible path for the holes through tunneling to the electrode, due to the low energy barrier at the PV2000/h‐BN interface. Using h‐BN as an EBL, efficient inverted OPVs are achieved with an average solar‐to‐power conversion efficiency of 6.13%, which is comparable with that of reference devices based on MoO 3 (7.3%) and PEDOT:PSS (7.6%) as HTLs. Interestingly, the devices with h‐BN shows great light‐soak stability. The study reveals that the monolayer h‐BN grown by CVD could be an effective alternative EBL for the fabrication of efficient, lightweight, and stable OPVs.