有机太阳能电池是近些年来的一个研究热点。由于其本身的轻便、柔性、较低的成本以及可印刷的特性，一大批研究人员为其投入心血。在本论文中，我们设计并合成了一种宽带隙聚合物给体材料和一种低稠环的小分子受体材料，从给受体的结构设计和器件性能测试上系统研究了聚合物有机太阳能电池。 1. 为了开发用于非富勒烯聚合物太阳能电池的宽带隙给体材料，使用双羧酸酯取代的苯并二噻吩（BDTC）作为电子受体（A）单元，与5-烷基噻吩-2-基取代的苯并二噻吩（BDT）或5-硫烷基噻吩-2-基取代的BDT给体单元共聚分别得到D-A交替的聚合物PBDT-BDTC和PBDTS-BDTC。PBDT-BDTC和PBDTS-BDTC的带隙都超过了1.90eV，属于典型的宽带隙聚合物，并且它们的最高占据分子轨道（HOMO）能级都低于-5.50eV。这两种聚合物的吸收和能级与窄带隙受体ITIC-Th匹配良好。给受体在300至900nm内形成良好的吸收互补，HOMO能级差约为0.15eV。制备倒置器件实现了高于7％的功率转换效率。此外，加入0.5％1,8-二碘辛烷（DIO）作为添加剂，基于PBDT-BDTC的器件表现出比基于PBDTS-BDTC的器件更好的光伏性能。基于PBDT-BDTC器件的最优PCE为8.32％，开路电压（Voc）为0.92 V，短路电流密度（Jsc）为13.91 mA / cm2，填充因子（FF）为65.21％，这表明PBDT-BDTC是一种有前景的聚合物给体材料。 2. 设计并合成了一种以两个偶联的噻吩并环戊二烯结构单元的、低稠环的A-D-A型结构小分子受体M1，在M1的端基上引入甲基，得到小分子受体M2。甲基的引入使得分子的LUMO能级从-3.83eV提升至-3.79eV。这两种小分子在550-850nm的范围内有着良好的吸收，与聚合物给体PBDB-T的光谱和能级匹配良好。基于PBDB-T:M1的倒置器件开路电压为0.82V，短路电流为16.39 mA / cm2，填充因子为61.36%，最终的能量转换效率为8.24%。基于PBDB-T:M2的倒置器件在添加1-氯萘（1-CN）优化之后，各项参数都有所增加：开路电压为 0.86V，短路电流为 16.78mA / cm2，填充因子为64.00%，最终的能量转换效率为9.22%。以上结果表明该类型简单易合成的低稠环小分子受体具有良好的发展前景。

Organic solar cell is a research hotspot in recent years. A large number of researchers have devoted their efforts to it because of its light weight, flexibility, low cost and large area printing. In this paper, a wide bang-gap polymer as donor and a low-fused ring small molecule as acceptor were designed and synthesized. Photovoltaic device performance of the polymer donor and the small molecule acceptor was studied. 1. To develop wide bandgap donor materials for high performance nonfullerene polymer solar cells (NF PSCs), bis(carboxylate) substituted benzo[1,2-b:4,5-b]di-thiophene (BDTC) weak electron acceptor (A) unit was used to polymerize with 5-alkylthiophene-2-yl-substituted benzo[1,2-b:4,5-b]di-thiophene (BDT) or 5-alkylthiothiophene-2-yl-substituted BDT donor unit to construct donor-acceptor (D-A) alternative polymers PBDT-BDTC and PBDTS-BDTC, respectively. PBDT-BDTC and PBDTS-BDTC exhibit wide bandgaps over 1.90 eV and low lying highest occupied molecular orbital (HOMO) levels below -5.50 eV. The absorption and energy levels of these two polymers match well with those of the typical low bandgap acceptor ITIC-Th, resulting in a good complementary absorption from 300 to 900 nm and a low HOMO level offset of about 0.15 eV. NF PSCs with an inverted device structure were fabricated and power conversion efficiencies (PCEs) higher than 7% were achieve. Furthermore, PBDT-BDTC based PSCs exhibit much better photovoltaic performance than PBDTS-BDTC based ones after the treatment with 0.5% 1,8-diiodooctane (DIO). The optimized devices gave a PCE of 8.32% with an open-circuit voltage (Voc) of 0.92 V, a short-circuit current density (Jsc) of 13.91mA/cm2, and a fill factor (FF) of 65.21%, indicating that PBDT-BDTC is a promising polymer donor for NF PSCs. 2. Two low-fused ring small molecule receptors M1 and M2 with A-D-A structure were designed and synthesized. M1 consists of two coupled thiophene cyclopentadiene units as the central unit and 2-(3-oxo-2,3-dihydroinden-1-ylidene)-malononitrile (IC) as the terminal group. The methyl group on the IC provided M2. The LUMO level for M1 was raised from 3.83 eV to 3.79 eV for M2. These two small molecules have good absorption in the range of 550-850 nm which match well with the polymer donor PBDB-T. As for device based on M1 and PBDB-T, the Voc of the inverted device was 0.82V, the Jsc was 16.39 mA/cm2, the FF was 61.36%, and the PCE was 8.24%. For PBDB-T:M2 based optimized device, all parameters were increased: the Voc was 0.86V, the Jsc was 16.78mA/cm2, the FF was 64.00%, and the PCE was 9.22%. This indicates that this type of simple and easily synthesized small molecule acceptor has a good development prospect.