%0 Journal Article
%T <br>
%A 刘志玺
%A 张书华
%A 张志国
%A 李昌治
%A 李永舫
%A 章中强
%A 陈红征
%J 物理化学学报
%D 2019
%R 10.3866/PKU.WHXB201805091
%X 非富勒烯电子受体由于其吸收强，能级可调，稳定性好等优点，近年来受到研究者的广泛关注，并且光电转换效率已突破14%。在本研究中，我们设计并合成了一种结构简单，易于合成的非稠环结构的非富勒烯电子受体ICTP。通过合理的结构设计，利用分子内的非共价作用力，实现了高的空间平面性。其在长波长区域宽且强的吸收和合适的能级水平，使得ICTP适合与许多聚合物给体材料搭配，制备太阳能电池。基于PBDB-T:ICTP的聚合物太阳能电池取得了4.43%的光电转换效率和0.97 V的开路电压。<br>Non-fullerene electron acceptors have attracted enormous attention of the research community owing to their advantages of optoelectronic and chemical tunabilities for promoting high-performance polymer solar cells (PSCs). Among them, fused-ring electron acceptors (FREAs) are the most popular ones with the good structural planarity and rigidity, which successfully boost the power conversion efficiencies (PCEs) of PSCs to over 14%. In considering the cost-control of future scale-up applications, it is also worthwhile to explore novel structures that are easy to synthesize and still maintain the advantages of FREAs. In this work, we design and synthesize a new electron acceptor with an unfused backbone, 5, 5'-((2, 5-bis((2-hexyldecyl)oxy)-1, 4-phenylene)bis(thiophene-2-yl))bis(methanylylidene)) bis(3-oxo-2, 3-dihydro-1H-indene-2, 1-diylidene))dimal-ononitrile (ICTP), which contains two thiophenes and one alkoxy benzene as the core and 2-(3-oxo-2, 3-dihydroinden-1-ylidene) malononitrile (IC) as the terminal groups. The synthetic route to ICTP involves only three steps, with high yields. Density functional theory calculations indicate that the non-covalent interactions, O…H and O…S, help reinforce the space conformation between the central core and the terminals. ICTP shows broad and strong absorption in the long-wavelength range between 500 and 760 nm. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels of ICTP were measured to be -5.56 and -3.84 eV by cyclic voltammetry. The suitable absorption and energy levels make ICTP a good acceptor candidate for medium bandgap polymer donors. The best devices based on PBDB-T:ICTP showed a PCE of 4.43%, with an open circuit voltage (VOC) of 0.97 V, a short circuit current density (JSC) of 8.29 mA？cm-2, and a fill factor (FF) of 0.55, after adding 1% 1, 8-diiodooctane (DIO) as the solvent additive. Atomic force microscopy revealed that DIO could ameliorate the strong aggregation in the blended film and lead to a smoother film surface. The hole and electron mobilities of the optimized device were measured to be 9.64 and 2.03 × 10-5 cm2？V-1？s-1, respectively, by the space-charge-limited current method. The relatively low mobilities might be responsible for the moderate PCE. Further studies can be performed to enlarge the conjugation length by
%U http://www.whxb.pku.edu.cn/CN/Y2019/V35/I4/394