950223-95-7Relevant academic research and scientific papers
Isomeric effects of chlorinated end groups on efficient solar conversion
Mo, Daize,Chen, Hui,Zhou, Jiadong,Han, Liang,Zhu, Yulin,Chao, Pengjie,Zheng, Nan,Xie, Zengqi,He, Feng
, p. 23955 - 23964 (2020/12/03)
Isomers with subtle differences in their molecular structure often exhibit different electronic/optoelectronic properties, charge-transport behaviors and photovoltaic performances. In this work, we describe BTIC-2Cl-γ, BTIC-2Cl-δ, and BTIC-2Cl-β, three isomers with acceptor-donor-acceptor-donor-acceptor (A-D-A-D-A) structures, in which a fused benzothiadiazole is the donor (D) unit and a single chlorine atom substituted at the δ, β or γ position of the benzene-fused end groups is the acceptor (A) unit. In general, changes in the position of the chlorine atom were found to lead to significantly different absorptions, energy levels, and photovoltaic performances. Compared to BTIC-2Cl-δ, the BTIC-2Cl-γ isomer shows similar UV/Vis absorption, energy levels, and molecular packing, but slightly better photovoltaic performance. A crystallographic analysis of BTIC-2Cl-δ indicates that the molecules easily form a three-dimensional (3D) network due to the noncovalent interactions of Cl?S, Cl?π and Cl?N. When blended with PBDB-TF as an electron-donor material, the devices based on BTIC-2Cl-γ exhibited higher power conversion efficiency (PCE) of up to 15.04% with an increased voltage (Voc) of 0.90 V, which was better than that of BTIC-2Cl-δ-based devices (14.13%) and much higher than that of BTIC-2Cl-β-based devices (7.39%). Our studies demonstrate that having the chlorine atom at the different positions of the end groups clearly affects the photovoltaic properties of the resulting acceptors.
Synthesis and photovoltaic properties of D-π-A copolymers based on thieno[3,2-b]thiophene bridge unit
Li, Zhaojun,Huo, Lijun,Guo, Xia,Yong, Weina,Zhang, Shaoqing,Fan, Huili
, p. 6150 - 6157 (2013/10/22)
Three D-π-A copolymers containing thieno[3,2-b]thiophene (TT) bridge and BDT, carbazole, fluorene as D units and benzothiadiazole as A unit were synthesized and characterized. These copolymers of PBDT-tt-BT, PC-tt-BT and PF-tt-BT exhibited enough high thermal stabilites and good solubilites in chloroform and dichlorobenzene. Among the copolymers, with the increase of the electron-donating abilities of the D units from fluorene to carbazole further to BDT, the absorption spectra of PF-tt-BT shows blue shift and that of PBDT-tt-BT shows red shift comparing to that of PC-tt-BT in their solutions and films. Meanwhile, by electrochemical cyclic voltammetry measurements we found the HOMO levels vary in the same trench according to their electron-donating abilities. Under the illumination of AM 1.5G, 100 mW/cm2, power conversion efficiency (PCE) of the PSCs based on these copolymers as donors and PC 70BM as acceptor were measured and PBDT-tt-BT shows a higher efficiency of 4.91% than PC-tt-BT and PF-tt-BT based devices mostly due to its higher hole mobility and broader absorption range. These results indicate that PBDT-tt-BT is a promising photovoltaic polymer donor material for efficient PSCs.
Design, synthesis and photovoltaic properties of a new D-π-A polymer with extended π-bridge units
Guo, Xia,Zhang, Maojie,Huo, Lijun,Xu, Feng,Wu, Yue,Hou, Jianhui
, p. 21024 - 21031 (2013/02/23)
New low band gap copolymers PBDTT-DTTBT and PBDTT-DTBT using BDT-T and BT as donor and acceptor, with different π-bridge units thieno[3,2-b]thiophene and thiophene, respectively, were synthesized. The absorption spectra, electronic energy levels, and phot
