Three dimensional (3D) acceptor‐donor‐acceptor (A−D‐A) type small molecules (M1, M2, M3 and M4) are theoretically investigated for optoelectronic properties. The designed molecules contain spirobifluorene as core unit linked with end capped acceptors through four four thieno‐[3,2‐b]Thiophene (TT) units. The end capped acceptors are (3‐methyl‐2‐thioxothiazolidin‐4‐one) (M1), 2‐(2‐ethylidene‐5,6‐difluoro‐3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (M2), 2‐(3‐ethyl‐4‐oxothiazolidin‐2‐ylidine)malononitrile (M3) and 2‐(2‐ethylidene‐5,6‐dicyano‐3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (M4). The photovoltaic parameters of the designed molecules are compared with the recently reported reference compound R. Among all designed molecules, M4 is a low energy gap material (2.28 eV), broad absorption which is attributed to excellent communication between strong electron withdrawing end capped acceptors through extended conjugation. All newly designed molecules have lower binding energy as compared to reference molecule R which results in higher exciton dissociation in excited state. The reorganization energy calculations indicate good charge transfer ability of the designed molecules. M4 shows the lowest λ_e (0.0022) value with respect to the reference molecule R (0.034) which signifies its enhanced electronic transport behavior. The calculated open circuit voltages (V_oc) ranges from 1.97 to 2.36 eV, 2.11 to 2.49 eV and 1.9 eV to 2.28 eV with respect to three different well known donor materials PTB7‐Th, PBDB−T and P3HT, respectively.

中文翻译：

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设计具有高效光伏参数的三维（3D）非富勒烯小分子受体

从理论上研究了三维（3D）受体-受体-受体（AD-A）型小分子（M1，M2，M3和M4）的光电性能。设计的分子包含螺二芴作为核心单元，并通过四个四个噻吩并[3,2-b]噻吩基（TT）单元与封端的受体连接。封端的受体是（3-甲基-2-硫代噻唑啉酮-4-酮）（M1），2-（2-亚乙基-5-5,6-二氟-3-氧代-2-，3-二氢茚基-1-亚烷基）丙二腈（M2），2-（3-乙基-4-氧噻唑啉-2-酮）丙二腈（M3）和2-（2-亚乙基-5,6-二氰基-3-氧代-2-，3-二氢茚满-1-基丙二腈（M4）。将设计分子的光伏参数与最近报道的参考化合物R进行比较。在所有设计的分子中，M4是一种低能隙材料（2.28 eV），具有广泛的吸收性，这归因于强电子吸收末端封端的受体通过扩展共轭之间的出色连通性。与参考分子R相比，所有新设计的分子均具有较低的结合能，从而在激发态下导致更高的激子解离。重组能的计算表明所设计的分子具有良好的电荷转移能力。M4表示最低λ _È（0.0022）相对于参照分子值ř（0.034）表示其增强的电子传输行为。相对于三种不同的众所周知的供体材料PTB7-Th，PBDB-T和P3HT，计算出的开路电压（V _oc）范围分别为1.97至2.36 eV，2.11至2.49 eV和1.9 eV至2.28 eV。