Two novel T-shaped π-conjugated small molecules of DTNT-3DPP and DTNT(DPP-PN)3 with 4,9-di(thiophen-2-yl)naphtho[2,3-b]thiophene (DTNT) as the donor core and diketopyrrolopyrrole (DPP) as acceptor arms, in the latter case incorporating phenanthrene (PN) units, have been designed and synthesized. The effects of the central core and terminal units on the optical, thermal, electrochemical, and photovoltaic properties have been investigated. It was found that DTNT-3DPP and DTNT(DPP-PN)3 exhibit better light-harvesting and charge-transport properties than triphenylamine (TPA)-based star-shaped molecules. DTNT-3DPP and DTNT(DPP-PN)3 were used as donor materials and methyl [6,6]-phenyl-C71-butyrate (PC71BM) as the acceptor for the fabrication of solution-processed bulk heterojunction (BHJ) solar cells. The power conversion efficiencies (PCEs) of solar cells based on DTNT-3DPP and DTNT(DPP-PN)3 are 3.47 and 3.69 %, respectively. These PCEs are higher than those of the corresponding TPA-based solar cells (1.91 and 3.67 %). Our work indicates that the planar DTNT unit can improve the photovoltaic properties of organic small molecules relative to those of the TPA unit.

中文翻译：

---

两种基于 4,9-二(噻吩-2-基)萘并[2,3-b]噻吩的 T 形供体-受体小分子用于溶液法有机太阳能电池

DTNT-3DPP 和 DTNT(DPP-PN)3 两种新型 T 型 π 共轭小分子，以 4,9-二(噻吩-2-基)萘并[2,3-b]噻吩 (DTNT) 作为供体已经设计和合成了核心和二酮吡咯并吡咯（DPP）作为受体臂，在后一种情况下包含菲（PN）单元。已经研究了中央核心和终端单元对光学、热、电化学和光伏特性的影响。发现DTNT-3DPP和DTNT(DPP-PN)3比三苯胺(TPA)基星形分子表现出更好的光捕获和电荷传输特性。DTNT-3DPP 和 DTNT(DPP-PN)3 用作供体材料，[6,6]-苯基-C71-丁酸甲酯 (PC71BM) 作为受体，用于制造溶液处理的体异质结 (BHJ) 太阳能电池。基于DTNT-3DPP和DTNT(DPP-PN)3的太阳能电池的功率转换效率(PCE)分别为3.47%和3.69%。这些 PCE 高于相应的基于 TPA 的太阳能电池（1.91 和 3.67 %）。我们的工作表明，相对于 TPA 单元，平面 DTNT 单元可以改善有机小分子的光伏性能。