Eight vegetable dyes extracted from flowers, fruits and leaves abundant in the wide biodiversity of the Andes region of South America were extracted with ethanol without purification to explore as vegetable photosensitizers in dye-sensitized solar cells (DSSCs). The absorbance spectra were measured by UV–visible spectroscopy and the photoelectrical performance of the DSSCs based on these dyes with a homemade solar simulator, constructed only for educational purposes under 1 sun of illumination. The open-circuit voltages (Voc) and the short-circuit photocurrent densities (Jsc) varied from 0.39 to 0.48 V and from 0.04 to 0.56 mA cm−2, and the power conversion efficiency (PCE) ranged from 0.01 to 0.18%. Particularly, the highest Voc and PCE values of the DSSCs sensitized by the ethanol extracts of Mortiño fruit (Vaccinium floribundum) and Jamaica flowers (Hibiscus sabdariffa) without purification were presumably associated with anthocyanin, the most effective component present in both vegetable photosensitizers. Hence, various components of the ethanol extracts obtained from these two vegetable dyes were purified by liquid–liquid extraction using different organic solvents of different polarity, namely petroleum ether, chloroform, ethyl acetate, n-butanol, and distilled water. Ethyl acetate resulted as the most favorable solvent for purification of ethanol extracts from Mortiño fruit and Jamaica flowers to use as vegetable photosensitizers in DSSCs. The PCE of the DSSC fabricated with the dye extracted in ethyl acetate from Mortiño fruit achieved 0.33%, with Voc of 0.520 V and Jsc of 1.014 mA cm−2, whereas the corresponding values obtained from the dye extracted from Jamaica flowers reached 0.22% with Voc of 0.541 V and Jsc of 0.678 mA cm−2. Thus, the purification of vegetable dyes used as photosensitizer impacts the photoelectrochemical performance of DSSCs.

中文翻译：

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溶剂对植物染料提取和纯化的影响，对染料敏化太阳能电池的效率产生影响

从南美安第斯山脉广泛生物多样性丰富的花朵，水果和叶子中提取的八种植物染料未经纯化就用乙醇提取，用于在染料敏化太阳能电池（DSSC）中用作植物光敏剂。用紫外可见光谱法测量吸收光谱，并用自制的太阳模拟器（基于教育目的）将基于这些染料的DSSC的光电性能测量出来，该模拟器仅用于1种光照下的教育目的。开路电压（Voc）和短路光电流密度（Jsc）在0.39至0.48 V和0.04至0.56 mA cm-2之间变化，功率转换效率（PCE）在0.01至0.18％范围内。尤其，未提纯的Mortiño果实（Vaccinium floribundum）和牙买加花（Hibiscus sabdariffa）的乙醇提取物敏化的DSSC的最高Voc和PCE值可能与花青素有关，后者是两种植物光敏剂中最有效的成分。因此，使用不同极性的不同有机溶剂，即石油醚，氯仿，乙酸乙酯，正丁醇和蒸馏水，通过液-液萃取纯化了从这两种植物染料中提取的乙醇提取物的各种成分。乙酸乙酯是纯化从Mortiño水果和牙买加花中提取的乙醇的最有利溶剂，可用作DSSC中的植物光敏剂。用从Mortiño水果中乙酸乙酯萃取的染料制备的DSSC的PCE达到0.33％，Voc为0.520 V，Jsc为1.014 mA cm-2，而Voc为0.520 V，Jsc为1.014 mA cm-2。因此，用作光敏剂的植物染料的纯化会影响DSSC的光电化学性能。