Unsymmetrical squaraine sensitizers with two different donor moieties, triphenylamine (NSQR) and heterotriangulene (NSQ1–3), for dye-sensitized solar cells (DSSCs) have been designed and synthesized. These dyes utilize the indolium moiety to control charge recombination dynamics at the TiO2-dye-electrolyte interface by connecting linear and branched alkyl functionalities. In the present study, an efficient heterotriangulene (HT) donor and a branched alkyl group at sp3-C atoms were strategically incorporated to increase the power conversion efficiency (PCE) of zwitterionic dyes by improving photo-current density (Jsc) and open-circuit potential (Voc) of the cell. Among these four dyes, NSQ3 exhibited the highest efficiency of 6.73% with a Jsc of 18.74 mA cm−2, Voc of 0.53 V, and fill factor (ff) of 68.3%, without any co-adsorbent under an irradiance of 100 mW cm−2 (simulated AM 1.5G sunlight). In the presence of 3α,7α-dihydroxy-5β-cholanic acid (CDCA), NSQ1, NSQ2 and NSQ3 showed an efficiency of 7.07%, 7.38% and 7.17%, respectively. Despite the low Voc, far red light harvesting efficiency, reduced dye aggregation, long lifetime (τ) of injected electrons and high quantum efficiency of NSQ1–3 played constructive roles in achieving high PCE efficiency. Deceleration of charge recombination for NSQ dye cells was further studied by electrochemical impedance spectroscopy (EIS) and open-circuit photo-voltage decay (OCVD) measurements.
具有两种不同供体部分的非对称方唑
染料敏化剂:
三苯胺(NSQR)和杂
三环烯(NSQ1–3),已被设计和合成为
染料敏化太阳能电池(DSSCs)。这些
染料利用
吲哚盐部分,通过连接线性和支链烷基功能性来控制TiO2-
染料-电解质界面上的电荷复合动力学。在本研究中,通过提高电池的光电流密度(Jsc)和开路电位(Voc),战略性地引入高效的杂
三环烯(HT)供体和sp3-C原子上的支链烷基,以提高两性离子
染料的功率转换效率(PCE)。在这四种
染料中,NSQ3在不加共吸附剂的照射下表现出最高的效率为6.73%,光电流密度为18.74 mA cm-2,开路电位为0.53 V,填充因子(ff)为68.3%,照射强度为100 mW cm-2(模拟
AM 1.5G阳光)。在存在3α,7α-二羟基-5β-
胆酸(
CDCA)的情况下,NSQ1,NSQ2和NSQ3分别表现出7.07%,7.38%和7.17%的效率。尽管开路电位较低,远红光收获效率、减少
染料聚集、注入电子的长寿命(τ)和高量子效率的NSQ1–3对实现高PCE效率起到了建设性作用。通过电
化学阻抗光谱(EIS)和开路光电压衰减(OCVD)测量进一步研究了NSQ
染料电池的电荷复合减速。