Alqurashy Bakhet A, Murad Ary R, Alsaedi Wael H, Altayeb Bader M, Elroby Shaaban A, Jedidi Abdesslem
Basic Science and Technologies Department, Applied College, Taibah University, Madina 42353, Saudi Arabia.
Department of Chemistry, College of Science, Charmo University, Chamchamal, Sulaymaniyah 46023, Iraq.
Polymers (Basel). 2025 Jul 27;17(15):2050. doi: 10.3390/polym17152050.
In the present study, two novel donor-acceptor (D-A) conjugated copolymers, PIDTBDI and PIDTTBDI, were successfully synthesized via Stille coupling polymerization. These alternating copolymers incorporate indacenodithiophene and indacenodithienothiophene as donor units, coupled with benzothiadiazole dicarboxylic imide as the electron-deficient acceptor unit. The influence of extended conjugation on the structural, optical, thermal, and electrochemical properties of the copolymers was systematically investigated and confirmed by density functional theory (DFT). XRD analysis confirmed that both polymers are amorphous. Thermogravimetric analysis revealed that both materials possess excellent thermal stability, with decomposition temperatures exceeding 270 °C. The theoretical and experimental values of the energy gap confirmed the thermal stability of the studied polymers. The molecular weight was determined to be 10,673 Da for PIDTBDI and 7149 Da for PIDTTBDI. Despite the variation in molecular weight, both copolymers exhibited comparable optical and electrochemical bandgaps of approximately 1.57 and 1.69 eV, respectively. Electrochemical measurements showed that PIDTBDI has a HOMO energy level of -5.30 eV and a LUMO level of -3.61 eV, while PIDTTBDI displays HOMO and LUMO levels of -5.28 eV and -3.59 eV, respectively. These results indicate that minor structural differences can considerably affect the electronic characteristics of the polymers, thus altering their overall efficacy in solar cell applications.
在本研究中，通过Stille偶联聚合成功合成了两种新型供体-受体（D-A）共轭共聚物PIDTBDI和PIDTTBDI。这些交替共聚物包含茚并二噻吩和茚并二噻吩并噻吩作为供体单元，与苯并噻二唑二羧酸亚胺作为缺电子受体单元相连。通过密度泛函理论（DFT）系统地研究并证实了扩展共轭对共聚物的结构、光学、热学和电化学性质的影响。XRD分析证实这两种聚合物均为非晶态。热重分析表明这两种材料都具有优异的热稳定性，分解温度超过270℃。能隙的理论值和实验值证实了所研究聚合物的热稳定性。测定PIDTBDI的分子量为10,673 Da，PIDTTBDI的分子量为7149 Da。尽管分子量有所不同，但两种共聚物的光学和电化学带隙分别约为1.57和1.69 eV，具有可比性。电化学测量表明，PIDTBDI的HOMO能级为-5.30 eV，LUMO能级为-3.61 eV，而PIDTTBDI的HOMO和LUMO能级分别为-5.28 eV和-3.59 eV。这些结果表明，微小的结构差异会显著影响聚合物的电子特性，从而改变它们在太阳能电池应用中的整体效能。
