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Organic Electronics
journal homepage: www.elsevier.com/locate/orgel
A new dibenzo[g.p]chrysene derivative as an efficient anode buff er for
inverted polymer solar cells
Shulei Wang
a
, Ping Yang
b
, Kai Chang
a
, Wenxuan Lv
b
, Baoxiu Mi
a,*
, Juan Song
a,**
,
Xinyan Zhao
c,***
, Zhiqiang Gao
b,****
a
Institute of Advanced Materials (IAM), Key Laboratory for Organic Electronics & Information Displays (KLOEID), Nanjing University of Posts & Telecommunications
(NUPT), 9 Wenyuan Road, Nanjing, 210023, China
b
Jiangsu Engineering Center for Plate Displays & Solid State Lighting, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), School of Material
Science and Engineering, Nanjing University of Posts & Telecommunications (NUPT), 9 Wenyuan Road, Nanjing, 210023, China
c
Academy for Advanced Interdisciplinary Studies and Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology (SUSTech),
Shenzhen, 518055, China
ARTICLE INFO
Keywords:
Dibenzo[g,p]chrysene
Anode buffer
Inverted organic photovoltaic
Exciton/electron blocking
ABSTRACT
A new dibenzo[g,p]chrysene derivative, 3,6,11,14-tetramethoxyphenylamine- dibenzo[g,p]chrysene (MeOPhN-
DBC), has been designed and synthesized. This material shows good hole-transport ability, high thermal sta-
bility, and relatively high HOMO/LUMO, suitable for anode buffer in electronic devices. When 4 nm MeOPhN-
DBC was inserted between the active layer and MoO
3
to form double interfacial layers in the inverted polymer
solar cells based on poly (3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) blended
active layer, the power conversion efficiency was improved 24.7% compared to device with only MoO
3
buffer
(2.95% vs 3.68%). As demonstrated by photoluminescence, electrochemical impedance spectroscopy and the
atom force microscopy, as well as the energy level diagram, the insertion of MeOPhN-DBC inter layer can block
exciton quenching, improve electrical conductivity of the device, smooth interfacial contact, block electron flow
toward anode and thus suppress carrier recombination there, leading to improved hole extraction and OPV
device performance. This work demonstrates for the first time that dibenzo[g,p]chrysene derivatives can be
promising materials for anode buffer in electronic devices.
1. Introduction
Organic photovoltaic (OPV) is one of the important organic optoe-
lectronic devices that have potentials of low cost, large area, flexibility,
bio-compatibility, low-temperature and easy fabrication, as well as
being able to be utilized in portable and wearable electronic devices
[1–6]. OPV generally has a layered structure with organic layers
sandwiched between anode and cathode. After light harvesting by the
active organic materials, exciton dissociation and charge transport
occur in the organic layers, then electrons and holes are collected by
cathode and anode, respectively. Traditionally, OPV device adopts a
transparent anode to transmit light and collect holes, and a lower work
function metal cathode to collect electrons. However, the easily oxi-
dation of the low work-function cathode makes device long-term
stability problematic. Inverted OPV structure, which comprises high
work-function metals as top electrode to collect holes, is superior due to
the more inert feature of the top electrode [7,8]. Additionally, in ma-
terial systems containing fullerene-type acceptor, such as [6,6]-phenyl-
C61 butyric acid methyl ester (PCBM) mixed with poly (3-hex-
ylthiophene) (P3HT), the inverted device has more efficient charge
percolation channels, with the donor polymer locating predominantly
at the top of the active layer and the acceptor at the bottom, which is
consistent with charge collection directions in the device [9–11].
In inverted OPVs, poly (3, 4-thiophene): poly (styrenesulfonate)
(PEDOT:PSS) [12–14] or MoO
3
[15,16] are mostly used to modify the
noble metal anode Au [17–19]orAg[7,20–24]. The high-cost of noble
metals and the nonuniform wetting of PEDOT:PSS on the active-layer
surface are unsatisfactory issues related to these buffers and top
https://doi.org/10.1016/j.orgel.2019.07.022
Received 10 May 2019; Received in revised form 1 July 2019; Accepted 11 July 2019
*
Corresponding author.
**
Corresponding author.
***
Corresponding author.
****
Corresponding author.
E-mail addresses: iambxmi@njupt.edu.cn (B. Mi), iamjsong@njupt.edu.cn (J. Song), zhaoxy@sustc.edu.cn (X. Zhao), iamzqgao@njupt.edu.cn (Z. Gao).
Organic Electronics 74 (2019) 269–275
Available online 12 July 2019
1566-1199/ © 2019 Published by Elsevier B.V.
T