Kim Hwan Kyu
Global GET-Future Lab, Department of Advanced Materials Chemistry, Korea University 2511 Sejong-ro, Sejong 339-700, Korea.
ACS Omega. 2023 Feb 6;8(7):6139-6163. doi: 10.1021/acsomega.2c06843. eCollection 2023 Feb 21.
A redox electrolyte is a crucial part of dye-sensitized solar cells (DSSCs), which plays a significant role in the photovoltage and photocurrent of the DSSCs through efficient dye regeneration and minimization of charge recombination. An I/I redox shuttle has been mostly utilized, but it limits the open-circuit voltage ( ) to 0.7-0.8 V. To improve the value, an alternative redox shuttle with more positive redox potential is required. Thus, by utilizing cobalt complexes with polypyridyl ligands, a significant power conversion efficiency (PCE) of above 14% with a high of up to 1 V under 1-sun illumination was achieved. Recently, the of a DSSC has exceeded 1 V with a PCE of around 15% by using Cu-complex-based redox shuttles. The PCE of over 34% in DSSCs under ambient light by using these Cu-complex-based redox shuttles also proves the potential for the commercialization of DSSCs in indoor applications. However, most of the developed highly efficient porphyrin and organic dyes cannot be used for the Cu-complex-based redox shuttles due to their higher positive redox potentials. Therefore, the replacement of suitable ligands in Cu complexes or an alternative redox shuttle with a redox potential of 0.45-0.65 V has been required to utilize the highly efficient porphyrin and organic dyes. As a consequence, for the first time, the proposed strategy for a PCE enhancement of over 16% in DSSCs with a suitable redox shuttle is made by finding a superior counter electrode to enhance the fill factor and a suitable near-infrared (NIR)-absorbing dye for cosensitization with the existing dyes to further broaden the light absorption and enhance the short-circuit current density ( ) value. This review comprehensively analyzes the redox shuttles and redox-shuttle-based liquid electrolytes for DSSCs and gives recent progress and perspectives.
氧化还原电解质是染料敏化太阳能电池（DSSC）的关键组成部分，它通过高效的染料再生和电荷复合的最小化，在DSSC的光电压和光电流中发挥着重要作用。I/I氧化还原穿梭体已被广泛使用，但它将开路电压（ ）限制在0.7 - 0.8V。为了提高 值，需要一种具有更正氧化还原电位的替代氧化还原穿梭体。因此，通过使用具有多吡啶配体的钴配合物，在1个太阳光照下实现了超过14%的显著功率转换效率（PCE），开路电压高达1V。最近，通过使用基于铜配合物的氧化还原穿梭体，DSSC的开路电压超过了1V，PCE约为15%。在室内应用中，使用这些基于铜配合物的氧化还原穿梭体，DSSC在环境光下的PCE超过34%，这也证明了DSSC商业化的潜力。然而，由于大多数已开发的高效卟啉和有机染料具有更高的正氧化还原电位，它们不能用于基于铜配合物的氧化还原穿梭体。因此，需要在铜配合物中替换合适的配体，或者使用氧化还原电位为0.45 - 0.65V的替代氧化还原穿梭体，以利用高效的卟啉和有机染料。因此，首次提出了一种策略，即通过找到一种优良的对电极来提高填充因子，并使用一种合适的近红外（NIR）吸收染料与现有染料进行共敏化，以进一步拓宽光吸收并提高短路电流密度（ ）值，从而使DSSC的PCE提高超过16%。这篇综述全面分析了用于DSSC的氧化还原穿梭体和基于氧化还原穿梭体的液体电解质，并给出了最新进展和展望。
