\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[greek,ngerman,english]{babel}



\usepackage{float}








\begin{document}

\title{Designing High-performance Nonfused Ring Electron Acceptors via
Side-chain Engineering}



\author[1]{Xinming Zheng}%
\author[1]{Wenlong Liu}%
\author[1]{Nan Wei}%
\author[2]{Andong Zhang}%
\author[1]{Guangliu Ran}%
\author[1]{Hongtao Shan}%
\author[2]{yahui liu}%
\author[2]{Hao Lu}%
\author[1]{Xinjun Xu}%
\author[3]{Zheng Tang}%
\author[1]{Wenkai Zhang}%
\author[1]{Zhishan Bo}%
\affil[1]{Beijing Normal University}%
\affil[2]{Qingdao University}%
\affil[3]{Donghua University}%


\vspace{-1em}



  
  \date{May 27, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
The side-chain has a significant effect on the optical properties and
aggregation behaviors of the organic small molecule acceptors, which
becomes an important strategy to optimize the photovoltaic performance
of organic solar cells (OSCs). In this work, we designed and synthesized
three novel nonfused ring electron acceptors (NFREAs) OC4-4Cl-Ph,
OC4-4Cl-Th and OC4-4Cl-C8 with hexylbenzene, hexylthiophene and octyl
side chains on the \selectlanguage{greek}π-\selectlanguage{english}bridge units. Compared with OC4-4Cl-Ph and
OC4-4Cl-Th, OC4-4Cl-C8 with linear alkyl side chain has more red-shift
absorption, which is conducive to obtaining higher short-circuit current
density. Additionally, the OC4-4Cl-C8 film exhibits a longer exciton
diffusion distance and the D18:OC4-4Cl-C8 blend film displays faster
hole transfer, weaker bimolecular recombination, and more efficient
exciton transport. Furthermore, the D18:OC4-4Cl-C8 blend films can form
good nano fibril-like interpenetrating networks, which can facilitate
exciton dissociation and charge transport. Finally, OC4-4Cl-C8 based
devices can generate an excellent PCE of 16.56\%, which is much higher
than OC4-4Cl-Ph (12.29\%) and OC4-4Cl-Th based (11.00\%) ones, being the
highest PCE among the NFREA based binary devices. All in all, we have
demonstrated that side-chain engineering is an efficient way to achieve
high-performance NFREAs.%
\end{abstract}%



\sloppy


\textbf{1. INTRODUCTION}

In recent years, organic solar cells (OSCs) are evolving rapidly due to
the growth of new photovoltaic materials and device engineering. The
single-junction OSCs power conversion efficiency (PCE) has surpassed
19\%,\textsuperscript{{[}1-8{]}} indicating tremendous potential for
future new energy applications. The low bandgap electron acceptors play
a picotal role in the rapid development of OSCs. Among them, the
commonly used high-performance electron acceptors are fused ring
electron acceptors (FREA) such as ITIC, Y6 and their
derivatives.\textsuperscript{{[}9-14{]}} However, the relatively complex
synthetic routes and low yields of FREAs still pose challenges for their
future commercial application. To simplify the synthetic route of
electron acceptors, nonfused ring electron acceptors (NFREAs) have
garnered more and more attention.\textsuperscript{{[}15-20{]}} However,
the photovoltaic performances of NFREAs are still far lagging behind
FREAs. To fabricate high-performance NFREAs, the varied side chain is an
important factor, which can largely affect the energy levels,
aggregation behavior, etc.\textsuperscript{{[}21-25{]}}

In recent years, several skeleton design strategies have been explored
for NFREAs.\textsuperscript{{[}18, 19, 26-30{]}} Hou et al. designed and
synthesized A4T-23, A4T-21, and A4T-16 with different side
groups,\textsuperscript{{[}17{]}} and demonstrated that A4T-16 with
large side groups has excellent photovoltaic performance because it can
form better stacking and a 3D network structure. Subsequently, NFREAs
TTC6, TT-C8T and TT-TC8,\textsuperscript{{[}31{]}} were prepared by
adjusting the molecular geometry through changing the steric hindrance
of the lateral substituents. Among them, TT-TC8 has a better planar
molecular skeleton and can form stronger intramolecular charge transfer
effect, exhibiting over 13\% PCE in OSCs with D18 as the donor polymer.

Based on the aforementioned considerations, we focus on the design and
synthesis of novel NFREAs using side chain engineering strategy. More
specifically, NFREAs\textbf{OC4-4Cl-Ph} ,\textbf{OC4-4Cl-Th} and
\textbf{OC4-4Cl-C8} have similar molecular skeletons, but different side
chains (hexylbenzene, hexylthiophene and octyl). Side chains can
effectively regulate the energy levels, absorption spectra, molecular
packings, and blend film morphology of acceptors. As a result,
\textbf{OC4-4Cl-C8} displays a maximum exciton diffusion length, and the
corresponding devices exhibit weaker bimolecular recombination, more
effective exciton transport, as well as higher and better balanced
mobility. Most encouragingly, devices based on \textbf{OC4-4Cl-C8}
demonstrated a champion PCE of 16.56\% with a good short-circuit current
(\emph{J} \textsubscript{sc}) (24.40 mA cm\textsuperscript{-2}) and a
suitable open-circuit voltage (\emph{V} \textsubscript{oc}) (0.90 V)
with a high fill factor (FF) (75.10\%). Our work shows that side-chain
engineering is an efficient approach to enable high-performance NFREAs.

2. RESULTS AND DISCUSSION

\textbf{2.1.} \textbf{Materials synthesis}

\textbf{Scheme 1.} The synthetic route of\textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} .

Reaction conditions: (i)
Pd\textsubscript{2}(dba)\textsubscript{3},\emph{S} -Phos,
K\textsubscript{3}PO\textsubscript{4}, toluene, 110\textsuperscript{o}C;
(ii) NBS, DMF, 0 \textsuperscript{o}C; (iii)
Pd(PPh\textsubscript{3})\textsubscript{4}, toluene,
110\textsuperscript{o}C; (iv) POCl\textsubscript{3}, 1,2-dichloroethane,
DMF, 85 \textsuperscript{o}C; (v) pyridine, CHCl\textsubscript{3},
25\textsuperscript{o}C.

The synthetic route of\textbf{OC4-4Cl-Ph} ,\textbf{OC4-4Cl-Th}
and\textbf{OC4-4Cl-C8} is outlined in \textbf{Scheme 1} . Compared to
FREA, these acceptors have fewer synthesis steps and higher yields. The
detailed synthesis process are described in the Supporting Information.
\emph{S} -Phos and Pd\textsubscript{2}(dba)\textsubscript{3} are used as
the catalyst precursors in a Suzuki cross-coupling of
3,6-dibromothieno{[}3,2-b{]}thiophene and (2,6-dibutoxyphenyl)boronic
acid to obtain compound \textbf{1} in a yield of about
85\%\textsuperscript{{[}32{]}}. Compound \textbf{2} is produced by
brominating compound 1 with N-bromosuccinimide in a yield of 95\%. Still
cross-couplings of compound \textbf{2} with
tributyl(6-(4-hexylphenyl)thieno{[}3,2-b{]}thiophen-2-yl)stannane
(\textbf{3a} ),
tributyl(6-(5-hexylthiophen-2-yl)thieno{[}3,2-b{]}thiophen-2-yl)stannane
(\textbf{3b)} or tributyl(6-octylthieno{[}3,2-b{]}thiophen-2-yl)stannane
(\textbf{3c} ) with Pd(PPh\textsubscript{3})\textsubscript{4} as the
catalyst affords the intermediates \textbf{4a} , \textbf{4b}
or\textbf{4c} , respectively. Compounds \textbf{5a} , \textbf{5b}
and\textbf{5c} are prepared by Vilsmeier-Haack reaction
(yield\textasciitilde{}89\%). The target acceptors\textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} are prepared by Knoevenagel
condensation in yields of approximately 75\%, and their structures were
characterization by \textsuperscript{1}H and \textsuperscript{13}C NMR
spectroscopy and mass spectroscopy.(Supporting Information).

\textbf{2.2.} \textbf{Optical and electrochemical properties}

The absorption spectra and energy levels of \textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} are displayed in Table 1
and Figure 2, respectively. In dilute chloroform
solutions,\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and
\textbf{OC4-4Cl-C8} exhibit intensely absorption in the range of 580 to
810 nm with the maximum absorption peak (\selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{max})
located at 738, 740 and 728 nm and their molar absorption coefficients
being estimated to be 1.50\selectlanguage{ngerman}×10\textsuperscript{5},
1.19×10\textsuperscript{5} and 1.52×10\textsuperscript{5}
cm\textsuperscript{-1} M\textsuperscript{-1}, respectively.

\textbf{Figure 1.} Chemical structures of the polymer donor and small
molecular acceptors.

From a solution to neat film, the absorption spectra of these three
acceptors are all prominently red-shifted. Compared
to\textbf{OC4-4Cl-Ph} and \textbf{OC4-4Cl-Th} , \textbf{OC4-4Cl-C8} neat
film displays a red-shifted and widened absorption ranging from 600 to
920 nm with the \selectlanguage{greek}\emph{λ} \selectlanguage{english}\textsubscript{max} located at 804 nm. In
addition, the optical band gaps (\emph{E}
\textsubscript{g}\textsuperscript{opt}) were calculated to be 1.39, 1.39
and 1.35 eV for \textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th}
and\textbf{OC4-4Cl-C8} , respectively. The electrochemical
characteristics of these three acceptors were determined by cyclic
voltammetry (CV). The HOMO and LUMO energy levels of \textbf{OC4-4Cl-Ph}
, \textbf{OC4-4Cl-Th}and \textbf{OC4-4Cl-C8} are calculated to be
-5.53/-3.93, -5.49/-3.89, and -5.50/-3.53 eV, respectively (Figure S3,
Figure S4 and Table 1).

\textbf{Figure 2.} UV-vis absorption spectra of \textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and\textbf{OC4-4Cl-C8} .

\textbf{Table 1.} Optical and electrochemical properties
of\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8.}\selectlanguage{english}
\begin{longtable}[]{@{}llllll@{}}
\toprule
\begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
Acceptor\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\selectlanguage{greek}\emph{λ}\selectlanguage{english}\textsubscript{max}\textsuperscript{{[}a{]}} (nm)\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\selectlanguage{greek}\emph{λ}\selectlanguage{english}\textsubscript{max}\textsuperscript{{[}b{]}} (nm)\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
\emph{E}\textsubscript{g}\textsuperscript{opt} (eV)\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
HOMO (eV)\strut
\end{minipage} & \begin{minipage}[b]{0.16\columnwidth}\raggedright\strut
LUMO (eV)\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textbf{OC4-4Cl-Ph}\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
738\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
782\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
1.39\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
-5.54\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
-3.90\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textbf{OC4-4Cl-Th}\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
740\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
783\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
1.39\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
-5.52\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
-3.92\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
\textbf{OC4-4Cl-C8}\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
728\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
804\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
1.35\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
-5.55\strut
\end{minipage} & \begin{minipage}[t]{0.14\columnwidth}\raggedright\strut
-3.94\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

{[}a{]} chloroform solutions. {[}b{]} thin films.

\textbf{2.3.} \textbf{Photovoltaic properties}

OSCs are fabricated with a conventional device structure of
ITO/PEDOT:PSS/acceptors:D18/PDINN/Ag to study the photoelectric
performance of \textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th}
and\textbf{OC4-4Cl-C8} . Optimization of the weight ratio between D18
and acceptors, thermal annealing temperature, and additive was
performed, for the corresponding optimization process is provided in the
supporting information. The \textbf{OC4-4Cl-C8} based devices can
achieve a champion PCE of 16.56\% with a good \emph{J}
\textsubscript{sc} (24.40 mA cm\textsuperscript{-2}) and a suitable
\emph{V} \textsubscript{oc} (0.90 V) with a high FF (75.10\%), which is
much higher than that\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image5/image5}

\end{center}
\end{figure}

\textbf{Figure 3} (a) J-V, (b) EQE, (c)\emph{J}
\textsubscript{ph}-\emph{V} \textsubscript{eff,} and (d)\emph{J}
\textsubscript{sc}-\emph{P} \textsubscript{light} curves of devices
based on \textbf{OC4-4Cl-}

\textbf{Table 2.} Photovoltaic parameters of devices based
on\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} .\selectlanguage{english}
\begin{longtable}[]{@{}lllll@{}}
\toprule
\begin{minipage}[b]{0.19\columnwidth}\raggedright\strut
Active layer\strut
\end{minipage} & \begin{minipage}[b]{0.19\columnwidth}\raggedright\strut
\emph{V}\textsubscript{OC} (V)\strut
\end{minipage} & \begin{minipage}[b]{0.19\columnwidth}\raggedright\strut
\emph{J}\textsubscript{SC} (mA/cm\textsuperscript{2})\strut
\end{minipage} & \begin{minipage}[b]{0.19\columnwidth}\raggedright\strut
FF (\%)\strut
\end{minipage} & \begin{minipage}[b]{0.19\columnwidth}\raggedright\strut
PCE max/ave (\%)\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
D18:\textbf{OC4-4Cl-Ph}\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
0.95\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
21.23 (20.80)\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
61.00\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
12.29 (12.03\selectlanguage{ngerman}±0.26)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
D18: \textbf{OC4-4Cl-Th}\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
0.92\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
20.08 (19.67)\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
59.31\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
11.00 (10.87\selectlanguage{ngerman}±0.13)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
D18: \textbf{OC4-4Cl-C8}\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
0.90\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
24.40 (23.71)\textsuperscript{a}\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
75.10\strut
\end{minipage} & \begin{minipage}[t]{0.17\columnwidth}\raggedright\strut
16.56 (16.31\selectlanguage{ngerman}±0.25)\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}\selectlanguage{ngerman}

\textsuperscript{a} Calculated by EQE curve.

\textbf{Table 3.} Energy loss analysis of \textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} based devices.\selectlanguage{english}
\begin{longtable}[]{@{}lllllll@{}}
\toprule
\begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
Active layer\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
\emph{E\textsubscript{g}} (eV)\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
\emph{E}\textsubscript{loss} (eV)\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
\emph{E}\textsubscript{ct} (eV)\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
[?]\emph{E}\textsubscript{1} (eV)\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
[?]\emph{E}\textsubscript{2} (eV)\strut
\end{minipage} & \begin{minipage}[b]{0.14\columnwidth}\raggedright\strut
[?]\emph{E}\textsubscript{3} (eV)\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
D18: \textbf{OC4-4Cl-Ph}\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.50\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.55\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.44\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.31\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.06\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.18\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
D18: \textbf{OC4-4Cl-Th}\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.49\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.57\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.43\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.32\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.06\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.19\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
D18: \textbf{OC4-4Cl-C8}\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.46\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.56\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
1.39\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.29\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.07\strut
\end{minipage} & \begin{minipage}[t]{0.12\columnwidth}\raggedright\strut
0.20\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

\emph{E} \textsubscript{loss} = \emph{E} \textsubscript{g} -\emph{qV}
\textsubscript{oc} = [?]\emph{E} \textsubscript{rad} + (\emph{E}
\textsubscript{g} - \emph{E} \textsubscript{ct}) + [?]\emph{E}
\textsubscript{nor-rad} = [?]\emph{E} \textsubscript{1} + [?]\emph{E}
\textsubscript{2} + [?]\emph{E} \textsubscript{3}

of \textbf{OC4-4Cl-Ph} (12.29\%) and \textbf{OC4-4Cl-Th} (11.00\%). As
far as we are aware, 16.56\% is the best PCEs for NFREA based devices.
Besides, the external quantum efficiency (EQE) measurement is further
investigated to confirm the \emph{J} \textsubscript{sc} values of OSCs.
As depicted in Figure 3b, \textbf{OC4-4Cl-Ph} and
\textbf{OC4-4Cl-Th}based devices exhibit a good light to electricity
response between 300 and 890 nm in wavelength; whereas the photocurrent
response region of\textbf{OC4-4Cl-C8} -based devices is obviously
red-shifted, being consistent with the UV-vis absorption results
(\emph{vide supra} ). Ulteriorly, the charge recombination behaviour was
measured to investigates the reasons for the different photovoltaic
parametrizations of \textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th}
and\textbf{OC4-4Cl-C8-} based OSCs. The charge dissociation
probabilities (\emph{P} \textsubscript{diss}) in the devices are
assessed using the photocurrent density (\emph{J} \textsubscript{ph}) vs
effective voltage (\emph{V} \textsubscript{eff}) curves. According to
Figure 3c, the\textbf{OC4-4Cl-C8} -based OSCs deliver higher exciton
dissociation efficiency (99.25\%) than \textbf{OC4-4Cl-Ph}(94.73\%) and
\textbf{OC4-4Cl-Th}(95.05\%) based ones, indicating that
D18:\textbf{OC4-4Cl-C8} based devices have higher exciton dissociation
and charge collection efficiency. Additionally, the light intensity
(\emph{P} \textsubscript{light}) dependent \emph{J}
\textsubscript{sc}characteristics (\emph{J\textsubscript{sc}} [?]\emph{P}
\textsubscript{light}\selectlanguage{greek}\textsuperscript{α}\selectlanguage{english}) can be used to investigated
the charge recombination process. As depicted in Figure 3d, the \selectlanguage{greek}α \selectlanguage{english}values
of \textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and\textbf{OC4-4Cl-C8}
based devices are 0.968, 0.950 and 0.977, respectively. Obviously, the \selectlanguage{greek}α
\selectlanguage{english}value of \textbf{OC4-4Cl-C8} is more approaching to 1, suggesting the
relatively weak bimolecular recombination and more efficient exciton
transport, thus achieving a higher FF value of the corresponding
devices.\textsuperscript{{[}33-35{]}}

Energy loss (\emph{E} \textsubscript{loss}) analysis is performed to
more fully understand the inpact of side chain engineering on\emph{V}
\textsubscript{oc} values. Furthermore, the\emph{E} \textsubscript{loss}
of these devices can be systematically studied by using highly sensitive
EQE (sEQE) and electroluminescence (EL)
measurements.\textsuperscript{{[}36-37{]}} As depicted in Figure S5, the
\emph{E} \textsubscript{loss} can be calculated from this
equation:\emph{E} \textsubscript{loss}\emph{=E}
\textsubscript{g}-\emph{qV} \textsubscript{oc}, where \emph{E}
\textsubscript{g} is defined based on the intersection of the absorption
and photoluminescence spectra of the low-bandgap acceptor. The \emph{E}
\textsubscript{g} values based on the\textbf{OC4-4Cl-Ph, OC4-4Cl-Th} and
\textbf{OC4-4Cl-C8} devices are 1.50, 1.49, and 1.46 eV, respectively.
Thus, the\emph{E} \textsubscript{loss} values of \textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} based devices are
calculated to be 0.55, 0.57 and 0.56 eV, respectively, which are
equivalent to the high-performance OSCs based on FREAs such as BTP-4Cl
(0.552 eV),\textsuperscript{{[}38{]}} L8-BO (0.556
eV),\textsuperscript{{[}39{]}} etc. Futhermore,\emph{E}
\textsubscript{loss} is generally contributed by charge generation
(\emph{E} \textsubscript{g}-\emph{E} \textsubscript{ct}, [?]\emph{E}
\textsubscript{2}) and charge recombination. The intersection of the
sEQE and EL Gaussian fitting curves can be used to determine\emph{E}
\textsubscript{ct} which stands for the charge transfer state energy. As
shown in Figure S6, hence, the charge generation energy loss (\selectlanguage{greek}Δ\selectlanguage{english}\emph{E}
\textsubscript{2}) values are calculated to be 0.06, 0.06 and 0.07 eV
for \textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and\textbf{OC4-4Cl-C8}
based devices, respectively. Further, the charge recombination energy
loss can be divided into radiative energy loss ([?]\emph{E}
\textsubscript{rad}, [?]\emph{E} \textsubscript{1}) and non-radiative
energy loss ([?]\emph{E} \textsubscript{nor-rad}, [?]\emph{E}
\textsubscript{3}). \selectlanguage{greek}Δ\selectlanguage{english}\emph{E} \textsubscript{3} can be calculated by the
equation: \selectlanguage{greek}Δ\selectlanguage{english}\emph{E} \textsubscript{3}= -\emph{kT}
ln(EQE\textsubscript{EL}), where \emph{k} and \emph{T} stand for the
temperature and the Boltzman constant, respectively. The [?]\emph{E}
\textsubscript{3} values of \textbf{OC4-4Cl-Ph} ,\textbf{OC4-4Cl-Th} and
\textbf{OC4-4Cl-C8} -based devices are 0.18, 0.19 and 0.20 eV,
respectively. Finally, by subtracting [?]\emph{E} \textsubscript{2} and
[?]\emph{E} \textsubscript{3} from\emph{E} \textsubscript{loss} it is
possible to calculate\emph{[?]E} \textsubscript{1} based on the
\textbf{OC4-4Cl-Ph, OC4-4Cl-Th}and \textbf{OC4-4Cl-C8} devices as 0.31,
0.32, and 0.29 eV, respectively. The higher \emph{E} \textsubscript{ct}
values and smaller energy loss can well explain the increased \emph{V}
\textsubscript{oc} of\textbf{OC4-4Cl-Ph} based devices. By using the
space charge limited current method, the hole (\selectlanguage{greek}\emph{μ}
\selectlanguage{english}\textsubscript{h}) and electron (\selectlanguage{greek}\emph{μ} \selectlanguage{english}\textsubscript{e}) transport
mobilities of \textbf{OC4-4Cl-Ph, OC4-4Cl-Th} and \textbf{OC4-4Cl-C8}
-based devices are calculated. The\selectlanguage{greek}\emph{μ} \selectlanguage{english}\textsubscript{h}/\selectlanguage{greek}\emph{μ}
\selectlanguage{english}\textsubscript{e} of\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and
\textbf{OC4-4Cl-C8} -based devices are
1.6\selectlanguage{ngerman}×10\textsuperscript{-4}/1.3×10\textsuperscript{-4},
1.5×10\textsuperscript{-4}/0.9×10\textsuperscript{-4} and
2.2×10\textsuperscript{-4}/2.0×10\textsuperscript{-4}cm\textsuperscript{2}
V\textsuperscript{-1} s\textsuperscript{-1}, respectively. The more
balanced higher and higher\selectlanguage{greek}\emph{μ} \selectlanguage{english}\textsubscript{h} and \selectlanguage{greek}\emph{μ}
\selectlanguage{english}\textsubscript{e} of\textbf{OC4-4Cl-C8} -based devices can be well
explained the relatively high \emph{J} \textsubscript{sc} and FF values.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image6/image6}

\end{center}
\end{figure}

\par\null

\textbf{Figure 4.}The decay dynamics of the singlet excitons in (a)
\textbf{OC4-4Cl-Ph} , (b) \textbf{OC4-4Cl-Th} and (c)\textbf{OC4-4Cl-C8}
films.

\textbf{2.4.} \textbf{Exciton diffusion lengths}

According to previous reports, a longer exciton diffusion distance is
help to suppress charge recombination, which is beneficial for
facilitates higher current density.\textsuperscript{{[}40{]}} Therefore,
the exciton diffusion lengths (\emph{L} \textsubscript{D}s) of
\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th}and \textbf{OC4-4Cl-C8} neat
films are estimated by using transient absorption spectroscopy (TAS) and
the exciton-exciton annihilation (EEA) model. The ground-state-bleaching
(GSB) signals (Figure S1) emerge after photoexcitation of
\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and\textbf{OC4-4Cl-C8} films
at 800 nm. The decay dynamics of the singlet excitons are shown in
Figure 4. The quenching of excitons is generally considered into two
parts: trap-induced recombination and bimolecular EEA process, which
corresponded to the rate decay parameters \selectlanguage{greek}\emph{κ}\selectlanguage{english}and \selectlanguage{greek}\emph{γ} ,
\selectlanguage{english}respectively, which can be used to calculate the exciton diffusion
coefficient (D). The calculated D values of\textbf{OC4-4Cl-Ph} ,
\textbf{OC4-4Cl-Th} and\textbf{OC4-4Cl-C8} are
4.72\selectlanguage{ngerman}×10\textsuperscript{-2}, 4.94 ×10\textsuperscript{-2} and
11.69×10\textsuperscript{-2}cm\textsuperscript{2} s\textsuperscript{-1},
respectively. The\emph{L} \textsubscript{D} values can be calculated by
the equation:\emph{L} \textsubscript{D}=(\emph{D}
\selectlanguage{greek}τ\selectlanguage{english})\textsuperscript{1/2}, where \selectlanguage{greek}τ \selectlanguage{english}is the exciton lifetime. The calculated
\emph{L} \textsubscript{D} values of\textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} are 10.01, 9.41 and 11.94
nm (Table S1), respectively. The large \emph{L} \textsubscript{D} values
of\textbf{OC4-4Cl-C8} mean the longer exciton diffusion distances, which
can effectively reduce the exciton
recombination.\textsuperscript{{[}41{]}}

\textbf{2.5. Charge generation kinetics}

The charge-generation process is studied using femtosecond transient
absorption (fs-TA) spectroscopy of the blend films. The contour plots of
the time-resolved absorption difference spectra of
D18:\textbf{OC4-4Cl-Ph} , D18:\textbf{OC4-4Cl-Th} and
D18:\textbf{OC4-4Cl-C8} blend films pumped at 800 nm are shown in Figure
5. The GSB signal of polymer donor can reflect the hole transfer
process.\textsuperscript{{[}42{]}} Specifically, the kinetics of 602 nm
is chosen to represent the D18 GSB dynamics. After excitation, strong
GSB peaks around short wavelength region (550--660 nm) appears
in\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8}
based blend films, which represents the hole transport at the D/A
interface. Biexponential function can be used to fit the hole transport
kinetic process.\textsuperscript{{[}43{]}} The hole transfer process
consists of an ultrafast hole transfer process at the D/A contact, as
defined by\selectlanguage{greek}\emph{τ} \selectlanguage{english}\textsubscript{1}, and a diffusion-mediated mechanism
that is significantly influenced by domain size and aggregation, as
defined by\selectlanguage{greek}\emph{τ} \selectlanguage{english}\textsubscript{2}\textsuperscript{{[}44{]}}.
The\selectlanguage{greek}\emph{τ} \selectlanguage{english}\textsubscript{1}/\selectlanguage{greek}\emph{τ} \selectlanguage{english}\textsubscript{2} are estimated
to be 2.46/23.95, 2.81/22.22 and 1.73/18.95 ps for the
\textbf{OC4-4Cl-Ph} ,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} blend
films, respectively. Therefore, the D18:\textbf{OC4-4Cl-C8} based device
is more conducive to the dissociation and diffusion of excitons, which
is more beneficial for improving the photovoltaic performance.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image7/image7}

\end{center}
\end{figure}

\textbf{Figure 5.} The TA image and the corresponding TA spectra of
D18:\textbf{OC4-4Cl-Ph} -based film with various decay times under 800
nm excitation (a and d); The TA image and the corresponding TA spectra
of D18:\textbf{OC4-4Cl-Th} based film with various decay times under 800
nm excitation (b and e); The TA image and the corresponding TA spectra
of D18:\textbf{OC4-4Cl-C8} based film with various decay times under 800
nm excitation (c and f); Kinetic traces of the blend films at the
selected wavelength under 800 nm excitation (g, h, i).\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image8/image8}

\end{center}
\end{figure}

\textbf{Figure 6.} AFM and TEM images of D18:\textbf{OC4-4Cl-C8} blend
film.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image9/image9}

\end{center}
\end{figure}

\textbf{Figure 7.} GIWAXS patterns of the neat\textbf{OC4-4Cl-Ph}
,\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} . films and the
D18:\textbf{OC4-4Cl-Ph} , D18: \textbf{OC4-4Cl-Th} , and
D18:\textbf{OC4-4Cl-C8} blend films.

\textbf{2.6. Morphology properties}

The surface and bulk morphologies of blend films based
on\textbf{OC4-4Cl-Ph, OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} are
investigated using the atomic force microscope (AFM) and transmission
electron microscopy (TEM) (Figure 6 and Figure S2). The root-mean-square
(RMS) roughness values of the D18:\textbf{OC4-4Cl-Ph} ,
D18:\textbf{OC4-4Cl-Th}and D18:\textbf{OC4-4Cl-C8} blend films are 1.67,
1.23 and 0.98 nm, respectively. Similarly, for TEM images, the
\textbf{OC4-4Cl-C8} based film can form nanoscale phase separation,
which is favorable for charge transport. The crystallinity and molecular
packing of neat and blend films are analyzed by GIWAXS measurements. As
depicted in Figure 7, many strong diffraction rings can be observed in
the 2D graphs of\textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and
\textbf{OC4-4Cl-C8} neat films, indicating their higher crystallinity.
For the blend films, D18:\textbf{OC4-4Cl-Ph} , D18:\textbf{OC4-4Cl-Th}
and D18:\textbf{OC4-4Cl-C8}blend films all exhibit distinct (010)
diffraction peaks in the out-of-plane direction, with \selectlanguage{greek}π--π \selectlanguage{english}stacking
distances of 3.78 \selectlanguage{ngerman}Å (1.66 Å\selectlanguage{english}\textsuperscript{-1}), 3.74 A (1.68
A\selectlanguage{english}\textsuperscript{-1}) and 3.67 A (1.71 A\selectlanguage{english}\textsuperscript{-1}),
respectively. Furthermore, the crystal coherence lengths (CCLs) of (010)
diffraction peaks are estimated to be 29.11, 34.50, and 37.29 nm for
D18:\textbf{OC4-4Cl-Ph} , D18:\textbf{OC4-4Cl-C8} , and
D18:\textbf{OC4-4Cl-Th} blend films, respectively, using the equation:
CCL=2\selectlanguage{greek}π/\selectlanguage{english}FWHM. The D18:\textbf{OC4-4Cl-C8} blend film have smaller
stacking distance and higher CCL value suggest the development of closer
molecular packing and higher crystallinity, which can promote charge
transport and endow better photovoltaic performance.

\textbf{3. CONCLUSION}

In summary, we have successfully designed and synthesized three novel
NFREAs \textbf{OC4-4Cl-Ph} , \textbf{OC4-4Cl-Th} and\textbf{OC4-4Cl-C8}
with hexylbenzene, hexylthiophene and octyl side chains at the \selectlanguage{greek}π-\selectlanguage{english}bridge
units. According to our results, the LUMO energy levels decrease from
\textbf{OC4-4Cl-Ph} to\textbf{OC4-4Cl-Th} and \textbf{OC4-4Cl-C8} .
Notably, the \textbf{OC4-4Cl-C8} exhibits a longer exciton diffusion
distance and the corresponding blend film (D18:\textbf{OC4-4Cl-C8} )
displays faster hole transfer and diffusion-mediated processes, weaker
bimolecular recombination, and more efficient exciton transport.
Furthermore, the D18:\textbf{OC4-4Cl-C8} blend films form favourable
nano fibril-like interpenetrating networks, which could facilitate
exciton dissociation and charge transport. Ultimately,
the\textbf{OC4-4Cl-C8} devices can achieve the highest PCE of 16.56\%
with a low \emph{E} \textsubscript{loss} of 0.56 eV, which is much
higher than\textbf{OC4-4Cl-Ph} (12.29\%) to \textbf{OC4-4Cl-Th}
(11.00\%) based ones. To the extent that we know, 16.56\% is the highest
PCEs of NFREA based devices up to now. Our work demonstrates that
side-chain engineering is an efficient way to fabricate high-performance
NFREAs.

Acknowledgements

Financial support from the National Natural Science Foundation of China
(52173174, 51933001, 22109080), the Natural Science Foundation of
Shandong Province (no. ZR2022YQ45), the Taishan Scholars Program (no.
tstp20221121 and no. tsqnz20221134). A portion of this work is based on
the data (GISAXS) obtained at BSRF-1W1A. The authors gratefully
acknowledge the cooperation of the beamline scientists at BSRF-1W1A
beamline.

Xinming Zheng and Wenlong Liu contributed equally to this work.

\textbf{Conflict of Interests}

The authors declare no conflict of interests.

\textbf{Date availability statement}

Supporting data are available from authors upon reasonablerequest.

\textbf{References}

{[}1{]} Y. Wei,~Z. Chen,~G. Lu,~N. Yu,~C. Li,~J. Gao,~X. Gu,~X. Hao,~G.
Lu,~Z. Tang,~J. Zhang,~Z. Wei,~X. Zhang,~H. Huang,~\emph{Adv. Mater.}
~\textbf{2022} ,~34, 2204718.

{[}2{]} M. Deng,~X. Xu,~Y. Duan,~L. Yu,~R. Li,~Q. Peng,~\emph{Adv.
Mater.} ~\textbf{2023} ,~35, 2210760.

{[}3{]} C. Han,~J. Wang,~S. Zhang,~L. Chen,~F. Bi,~J. Wang,~C. Yang,~P.
Wang,~Y. Li,~X. Bao,~\emph{Adv. Mater.} ~\textbf{2023} ,~35, 2208986.

{[}4{]} L. Zhu,~M. Zhang,~J. Xu,~C. Li,~J. Yan,~G. Zhou,~W. Zhong,~T.
Hao,~J. Song,~X. Xue,~Z. Zhou,~R. Zeng,~H. Zhu,~C. C. Chen,~R. C. I.
MacKenzie,~Y. Zou,~J. Nelson,~Y. Zhang,~Y. Sun,~F. Liu,~\emph{Nat.
Mater.} \textbf{~2022} ,~21,~656

{[}5{]} Z. Luo,~R. Ma,~J. Yu,~H. Liu,~T. Liu,~F. Ni,~J. Hu,~Y. Zou,~A.
Zeng,~C.-J. Su,~U.-S. Jeng,~X. Lu,~F. Gao,~C. Yang,~H.
Yan,~\emph{Kwansei Gakuin Univ. Nat. Sci. Rev.} ~\textbf{2022} ,~9,
nwac076.

{[}6{]} J. Wang,~Y. Wang,~P. Bi,~Z. Chen,~J. Qiao,~J. Li,~W. Wang,~Z.
Zheng,~S. Zhang,~X. Hao,~J. Hou,~\emph{Adv. Mater.} ~\textbf{2023} ,~35,
202301583

{[}7{]} L. Zhan,~S. Li,~Y. Li,~R. Sun,~J. Min,~Y. Chen,~J. Fang,~C. Q.
Ma,~G. Zhou,~H. Zhu,~L. Zuo,~H. Qiu,~S. Yin,~H. Chen,~\emph{Adv. Energy
Mater.} ~\textbf{2022} ,~12, 2201076.

{[}8{]} W. Gao,~F. Qi,~Z. Peng,~F. R. Lin,~K. Jiang,~C. Zhong,~W.
Kaminsky,~Z. Guan,~C. S. Lee,~T. J. Marks,~H. Ade,~A. K. Jen,~\emph{Adv.
Mater.} ~\textbf{2022} ,~34, 2202089.

{[}9{]} Q. Bai,~Q. Liang,~H. Li,~H. Sun,~X. Guo,~L.
Niu,~\emph{Aggregate} ~\textbf{2022} ,~3,~281.

{[}10{]} W. Zhao,~S. Li,~H. Yao,~S. Zhang,~Y. Zhang,~B. Yang,~J.
Hou,~\emph{J. Am. Chem. Soc.} ~\textbf{2017} ,~139,~7148.

{[}11{]} J. Yuan,~Y. Zhang,~L. Zhou,~G. Zhang,~H.-L. Yip,~T.-K. Lau,~X.
Lu,~C. Zhu,~H. Peng,~P. A. Johnson,~M. Leclerc,~Y. Cao,~J. Ulanski,~Y.
Li,~Y. Zou,~\emph{Joule.} ~\textbf{2019} ,~3,~1140.

{[}12{]} Y. Lin, J. Wang, Z.G. Zhang, H. Bai, Y. Li, D. Zhu, X. Zhan,
Adv. Mater. \textbf{2015} , 27 (7), 1170.

{[}13{]} S. Liu, J. Yuan, W. Deng, M. Luo, Y. Xie, Q. Liang, Y. Zou, Z.
He, H. Wu, Y. Cao, \emph{Nat. Photonics} . \textbf{2020} , 14 (5), 300.

{[}14{]} K. Jiang, Q. Wei, J.Y.L. Lai, Z. Peng, H.K. Kim, J. Yuan, L.
Ye, H. Ade, Y. Zou, H. Yan, \emph{Joule.} \textbf{2019} , 3 (12), 3020.

{[}15{]} X. Wang, H. Lu, Y. Liu, A. Zhang, N. Yu, H. Wang, S. Li, Y.
Zhou, X. Xu, Z. Tang, Z. Bo, \emph{Adv. Energy Mater} . \textbf{2021,}
11 (45), 2102591.

{[}16{]} Y. Liu, Z. Zhang, S. Feng, M. Li, L. Wu, R. Hou, X. Xu, X.
Chen, Z. Bo, \emph{J. Am. Chem. Soc\textbf{.}} \textbf{2017,} 139 (9),
3356.

{[}17{]} L. Ma, S. Zhang, J. Zhu, J. Wang, J. Ren, J. Zhang, J.
Hou,\emph{Nat. Commun} . \textbf{2021} , 12 (1), 5093.

{[}18{]} L. Ma,~S. Zhang,~J. Ren,~G. Wang,~J. Li,~Z. Chen,~H. Yao,~J.
Hou,~\emph{Angew. Chem. Int. Ed.} ~\textbf{2023} ,~62, e202214088.

{[}19{]} D. Ma, Q. Zhang, C. Li, \emph{Angew. Chem. Int. Ed.}
~\textbf{2023} , 62, e202214931.

{[}20{]} X. Zheng, W. Liu, H. Wang, X. Man, G. Ran, X. Yu, H. Lu, Z. Bi,
Y. Liu, A. Zhang, W. Ma, X. Xu, Z. Tang, W. Zhang, Z. Bo, Cell Rep.
Phys. Sci. \textbf{2022} , 101169.

{[}21{]} Y. Liu, B. Liu, C.-Q. Ma, F. Huang, G. Feng, H. Chen, J. Hou,
L. Yan, Q. Wei, Q. Luo, Q. Bao, W. Ma, W. Liu, W. Li, X. Wan, X. Hu, Y.
Han, Y. Li, Y. Zhou, Y. Zou, Y. Chen, Y. Li, Y. Chen, Z. Tang, Z. Hu,
Z.-G. Zhang, Z. Bo, \emph{Sci. China Chem} . \textbf{2022} , 65 (2),
224.

{[}22{]}
X.~Kong,~C.~Zhu,~J.~Zhang,~L.~Meng,~S.~Qin,~J.~Zhang,~J.~Li,~Z.~Wei,~Y.~Li,
Energy Environ. Sci.~\textbf{2022} , 15, 2011.

{[}23{]} G. Chai,~Y. Chang,~J. Zhang,~X. Xu,~L. Yu,~X. Zou,~X. Li,~Y.
Chen,~S. Luo,~B. Liu,~F. Bai,~Z. Luo,~H. Yu,~J. Liang,~T. Liu,~K. S.
Wong,~H. Zhou,~Q. Peng,~H. Yan,~\emph{Energy Environ. Sci.}
~\textbf{2021} ,~14,~3469.

{[}24{]} G. Chai,~Y. Chang,~Z. Peng,~Y. Jia,~X. Zou,~D. Yu,~H. Yu,~Y.
Chen,~P. C. Y. Chow,~K. S. Wong,~J. Zhang,~H. Ade,~L. Yang,~C.
Zhan,~\emph{Nano Energy.} ~\textbf{2020} ,~76, 105087.

{[}25{]} K. Liu, Y. Jiang, F. Liu, G. Ran, F. Huang, W. Wang, W. Zhang,
C. Zhang, J. Hou, X. Zhu, Adv. Mater. 2023, 35, 2300363.

{[}26{]} H. Huang, Q. Guo, S. Feng, C. Zhang, Z. Bi, W. Xue, J. Yang, J.
Song, C. Li, X. Xu, Z. Tang, W. Ma, Z. Bo, \emph{Nat.
Commun.}\textbf{2019} , 10, 3038.

{[}27{]} Y. Chen, M. Li, Y. Wang, J. Wang, M. Zhang, Y. Zhou, J. Yang,
Y. Liu, F. Liu, Z. Tang, Q. Bao, Z. Bo, Angew. Chem. Int. Ed.
Engl.\textbf{2020} , 59, 22714.

{[}28{]} C. Li, X. Zhang, N. Yu, X. Gu, L. Qin, Y. Wei, X. Liu, J.
Zhang, Z. Wei, Z. Tang, Q. Shi, H. Huang, Adv. Funct.
Mater.\textbf{2021} , 32, 2108861.

{[}29{]} X. Wang, H. Lu, J. Zhou, X. Xu, C. Zhang, H. Huang, J. Song, Y.
Liu, X. Xu, Z. Xie, Z. Tang, Z. Bo, ACS Appl. Mater.
Interfaces\textbf{2021} , 13, 39652.

{[}30{]} X. Wang,~R. Zeng,~H. Lu,~G. Ran,~A. Zhang,~Y. N. Chen,~Y.
Liu,~F. Liu,~W. Zhang,~Z. Tang,~Z. Bo,~\emph{Chin. J. Chem.}
~\textbf{2023} ,~41,~665;

{[}31{]} H. Lu, X. Wang, H. Wang, A. Zhang, X. Zheng, N. Yu, Z. Tang, X.
Xu, Y. Liu, Y. Chen, Z. Bo, Sci. China. Chem. 2022, 65, 594.

{[}32{]} X. Zheng, W. Liu, H. Lu, N.a. Yu, Y. Wang, H. Huang, S. Li, X.
Wang, H. Wang, Y. Liu, X. Xu, Z. Tang, Z. Bo, Chem. Eng. J.2022, 444,
136472.

{[}33{]} L. Yang, S. Shen, X. Chen, H. Wei, D. Xia, C. Zhao, N. Zhang,
Y. Hu, W. Li, H. Xin, J. Song, \emph{Adv. Funct. mater} . \textbf{2023}
, 33, 2303603.

{[}34{]} C. Yang,~S. Zhang,~J. Hou,~\emph{Aggregate} ~2022,~\textbf{3} ,
e111.

{[}35{]} T. Kim,~J. H. Kim,~T. E. Kang,~C. Lee,~H. Kang,~M. Shin,~C.
Wang,~B. Ma,~U. Jeong,~T. S. Kim,~B. J. Kim,~\emph{Nat. Commun.}
~2015,~\textbf{6} ,~8547.

{[}36{]} J. Wang,~R. Zhu,~S. Wang,~Y. Li,~B. Jia,~J. Zhou,~P. Xue,~S.
Seibt,~Y. Lin,~Z. Xie,~W. Ma,~X. Zhan,~\emph{Aggregate} ~2021,~2, e29.

{[}37{]} W. Liu,~R. Zhang,~Q. Wei,~C. Zhu,~J. Yuan,~F. Gao,~Y.
Zou,~\emph{Aggregate} ~2022,~3, e183.

{[}38{]} Y. Cui,~H. Yao,~J. Zhang,~T. Zhang,~Y. Wang,~L. Hong,~K.
Xian,~B. Xu,~S. Zhang,~J. Peng,~Z. Wei,~F. Gao,~J. Hou,~\emph{Nat.
Commun.} ~2019,~10,~2515.

{[}39{]} C. Li,~J. Zhou,~J. Song,~J. Xu,~H. Zhang,~X. Zhang,~J. Guo,~L.
Zhu,~D. Wei,~G. Han,~J. Min,~Y. Zhang,~Z. Xie,~Y. Yi,~H. Yan,~F. Gao,~F.
Liu,~Y. Sun,~\emph{Nat. Energy} ~2021,~6,~605.

{[}40{]} P. Bi, S. Zhang, Z. Chen, Y. Xu, Y. Cui, T. Zhang, J. Ren, J.
Qin, L. Hong, X. Hao, J. Hou, \emph{Joule} , 2021, 5, 2408.

{[}41{]} O. V. Mikhnenko, P. W. M. Blom, N. Thuc-Quyen, Energy Environ.
Sci. 2015, 8, 1867.

{[}42{]} Q. Wu, W. Wang, Y. Wu, Z. Chen, J. Guo, R. Sun, J. Guo, Y.
Yang, J. Min, Adv. Funct. Mater, 2021, 31, 2010411.

{[}43{]} Y. Zhong,~M. T. Trinh,~R. Chen,~G. E. Purdum,~P. P.
Khlyabich,~M. Sezen,~S. Oh,~H. Zhu,~B. Fowler,~B. Zhang,~W. Wang,~C.-Y.
Nam,~M. Y. Sfeir,~C. T. Black,~M. L. Steigerwald,~Y.-L. Loo,~F. Ng,~X.
Y. Zhu,~C. Nuckolls,~\emph{Nat. Commun.} ~2015,~6,~8242.

{[}44{]} M. Zhou,~C. Liao,~Y. Duan,~X. Xu,~L. Yu,~R. Li,~Q.
Peng,~\emph{Adv. Mater.} ~2023,~35, 2208279.

ToC figure

In this work, we designed and synthesized three brand-new nonfused ring
electron acceptors (NFREAs) OC4-4Cl-Ph, OC4-4Cl-Th and OC4-4Cl-C8 and
can be modularly synthesized. The OC4-4Cl-C8 exhibited longer exciton
diffusion distances and the corresponding blend film displayed faster
hole transfer and diffusion-mediated processes, weaker bimolecular
recombination, and more efficient exciton transport. Finally,
photovoltaic devices based on OC4-4Cl-C8 can generate an excellent PCE
of 16.56\%.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image10/image10}

\end{center}
\end{figure}

\selectlanguage{english}
\FloatBarrier
\end{document}

