Michael Grätzel Center for Mesoscopic Solar Cells, Wuhan National Laboratory for Optoelectronics and School of Optical and Electronic Information, Huazhong University of Science and Technology , Wuhan 430074, P. R. China.
ACS Appl Mater Interfaces. 2014 Mar 12;6(5):3448-54. doi: 10.1021/am405610b. Epub 2014 Feb 26.
In this study, new pull-push arylamine-fluorene based organic dyes zzx-op1, zzx-op2, and zzx-op3 have been designed and synthesized for p-type dye-sensitized solar cells (p-DSCs). In zzx-op1, a di(p-carboxyphenyl)amine (DCPA) was used as an electron donor, a perylenemonoimide (PMID) as an electron acceptor, and a fluorene (FLU) unit with two aliphatic hexyl chains as a π-conjugated linker. In zzx-op2 and zzx-op3, a 3,4-ethylenedioxythiophene (EDOT) and a thiophene were inserted consecutively between PMID and FLU to tune the energy levels of the frontier molecular orbitals of the dyes. The structural modification broadened the spectral coverage from an onset of 700 nm for zzx-op1 to 750 nm for zzx-op3. The electron-rich EDOT and thiophene lifted up the HOMO (highest occupied molecular orbital) levels of zzx-op2 and zzx-op3, making their potential more negative than zzx-op1. When three dyes were employed in p-type DSCs with I(-)/I3(-) as a redox couple and NiO nanoparticles as hole materials, zzx-op1 exhibited impressive energy conversion efficiency of 0.184% with the open-circuit voltage (VOC) of 112 mV and the short-circuit current density (JSC) of 4.36 mA cm(-2) under AM 1.5G condition. Density functional theory calculations, transient photovoltage decay measurements, and electrochemical impedance spectroscopic studies revealed that zzx-op1 sensitized solar cell exhibited much higher charge injection efficiency (90.3%) than zzx-op2 (53.9%) and zzx-op3 (39.0%), indicating a trade-off between spectral broadening and electron injection driving force in p-type DSCs.
在这项研究中，设计并合成了三种新型推拉芳基胺-芴基有机染料 zzx-op1、zzx-op2 和 zzx-op3，用于 p 型染料敏化太阳能电池（p-DSCs）。在 zzx-op1 中，二（对羧基苯基）胺（DCPA）用作电子给体，苝二酰亚胺（PMID）用作电子受体，芴单元带有两个脂肪族己基链作为π共轭连接体。在 zzx-op2 和 zzx-op3 中，PMID 和 FLU 之间连续插入了 3,4-亚乙基二氧噻吩（EDOT）和噻吩，以调整染料的前线分子轨道能级。结构修饰将光谱覆盖范围从 zzx-op1 的起始波长 700nm 拓宽至 zzx-op3 的 750nm。富电子的 EDOT 和噻吩抬高了 zzx-op2 和 zzx-op3 的 HOMO（最高占据分子轨道）能级，使它们的电位比 zzx-op1 更负。当这三种染料在以 I(-)/I3(-) 为氧化还原对的 p 型 DSCs 中，并以 NiO 纳米粒子作为空穴材料时，zzx-op1 表现出令人印象深刻的能量转换效率，在 AM 1.5G 条件下开路电压（VOC）为 112mV，短路电流密度（JSC）为 4.36mA cm(-2)。密度泛函理论计算、瞬态光电压衰减测量和电化学阻抗谱研究表明，zzx-op1 敏化太阳能电池的电荷注入效率（90.3%）远高于 zzx-op2（53.9%）和 zzx-op3（39.0%），表明在 p 型 DSCs 中，光谱展宽和电子注入驱动力之间存在权衡。
