Open Access“N‐ π ‐N” Type Oligomeric Acceptor Achieves an OPV Efficiency of 18.19% with Low Energy Loss and Excellent Stability
Author(s) -
Zhang Lili,
Zhang Ziqi,
Deng Dan,
Zhou Huiqiong,
Zhang Jianqi,
Wei Zhixiang
Publication year - 2022
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.202202513
Subject(s) - acceptor , materials science , thermal stability , monomer , energy conversion efficiency , thiophene , electron acceptor , absorption (acoustics) , analytical chemistry (journal) , chemistry , optoelectronics , organic chemistry , polymer , composite material , physics , condensed matter physics
A novel “N‐ π ‐N” type oligomeric acceptor of 2BTP‐2F‐T, constructed by two small non‐fullerene acceptor (NFA) units linked with a thiophene π bridge is reported. The 2BTP‐2F‐T not only combines the advantages of small NFA and polymeric acceptors (PYF‐T‐ o ) with similar units but also exhibits superior characteristics of high absorption coefficient and high electron moblity( µ e) ) with less dependence on molecular packing. Using PM6 as the donor, a remarkable efficiency of 18.19% is obtained with an open circuit ( V oc ) of 0.911 V, short current circuit ( J sc ) of 25.50 mA cm −2 , and fill factor (FF) of 78.3%, which is much better than that of the corresponding monomer (16.54%) and PYF‐T‐ o (15.8%) based devices. The much‐improved efficiency results from two aspects: 1) an enhanced FF due to the largely improved µ e and well‐controlled morphology ; 2) a higher value of ( J sc × V oc ) due to its higher absorption coefficient and efficient charge generation at a similar low energy loss. Furthermore, the PM6/2BTP‐2F‐T device possesses the longest T 80 lifetime to light‐soaking and comparable high thermal stability with PM6/PYF‐T‐ o . The results indicate that the “N‐ π ‐N” type oligomeric acceptor has a great application prospect due to its superior high efficiency and improved stability in organic solar cells.