Improper orientation and self-assembly of dyes on TiO₂ surface are the main disadvantages at the dye-TiO₂ interface that governs both charge injection and dye regeneration processes. In this report, a series of homo spiro-dimeric donor-π-spacer-acceptor (D-π-A) dyes based on bithiophene and terthiophene spacers with two-anchoring group containing dyes, TT₁, T₁T, TT₁T were designed and synthesized by Pd-catalyzed successive Suzuki coupling followed by direct arylation reactions. The position of branching centre in TT₁ and T₁T was systematically varied, where the spiro unit was placed near and away from the anchoring carboxylic acid unit, respectively. The dimeric spiro-dye T₁T showed device performance, which is 1.6 fold higher than its structural isomeric analogue TT₁, of 3.9% with a V_oc and J_sc of 0.593 V and 9.09 mA/cm², respectively, whereas for the isomeric analogue TT₁ a device performance of 2.45% (V_oc of 0.568 V and J_sc of 6.25 mA/cm²) under simulated 1 Sun (100 mW/cm²) condition. The improved V_oc for the dye T₁T compared to TT₁ dye was ascribed to the dipole moment exerted by the dyes on TiO₂ surface. Further the PCE of 4.16% (V_oc 0.589 V, J_sc 9.79 mA/cm² respectively) maximum was observed, when an extra thiophene unit was inserted in between the donor and π-spacer in dye TT₁T. The shifting the position of branching spiroBiProDOT π-spacer makes an impact on the device performance by synergistically enhancing both V_oc and J_sc.

染料在TiO ₂表面上的不正确取向和自组装是控制电荷注入和染料再生过程的染料-TiO ₂界面的主要缺点。在这份报告中，一系列的HOMO螺二聚体供体的π间隔子-受体（D- π -A）中的染料基于噻吩和三噻吩间隔物与两锚定基团的染料，TT ₁，T ₁ T，TT ₁ Ť通过钯催化的连续铃木偶联反应，然后进行直接芳基化反应，设计并合成了这些化合物。分支中心在TT ₁和T ₁ T中的位置螺环单元被系统地改变，其中螺环单元分别被放置在锚定羧酸单元附近和远离锚定羧酸单元。二聚螺旋染料T ₁ T的器件性能为3.9％，比其结构异构类似物TT ₁高1.6倍，V _oc和J _sc分别为0.593 V和9.09 mA / cm ²，而对于异构体类似物TT ₁在模拟1太阳（100 mW / cm ²）下的器件性能为2.45％（V _oc为0.568 V，J _sc为6.25 mA / cm ²）） 状况。与TT ₁染料相比，染料T ₁ T的V _oc改善归因于染料在TiO ₂表面上施加的偶极矩。进一步的4.16％的PCE（V _OC 0.589 V，Ĵ _SC 9.79毫安/厘米²分别地）观察到最大，当额外的噻吩单元中的供体和之间插入π间隔子在染料TT ₁ T.的换挡位置分支spiroBiProDOT的π间隔子通过协同增强二者使得对器件性能产生影响V_oc和J _sc。