Redox shuttles play a crucial role in the photovoltaic performance of dye-sensitized solar cells (DSSCs). A traditional iodide/triiodide (I^–/I₃^–) redox shuttle has been widely utilized in the first generation, but it suffers from intrinsic disadvantages such as a limited open-circuit voltage (V_OC). On the other hand, cobalt(II/III) complexes with polypyridyl ligands have been established as second-generation redox shuttles and have achieved a power conversion efficiency (η) of up to 13%. Since 2016, copper(I/II) complexes have appeared as third-generation redox shuttles owing to their more positive redox potentials. The η values of the copper-based DSSCs were low in the early stages, but to date, they have reached up to 13% as a result of modulating the molecular structures of the copper complexes and sensitizers. In this Perspective, recent developments in and prospects for copper-based DSSCs are highlighted, toward over 15% power conversion efficiency.

中文翻译：

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铜 (I/II) 配合物作为染料敏化太阳能电池的第三代氧化还原梭的出现

氧化还原穿梭在染料敏化太阳能电池 (DSSC) 的光伏性能中起着至关重要的作用。传统的碘化物/三碘化物 (I ^– /I ₃ ^– ) 氧化还原梭已在第一代中得到广泛应用，但它存在一些固有缺点，例如开路电压有限 ( V _OC）。另一方面，具有多吡啶基配体的钴 (II/III) 配合物已被确立为第二代氧化还原穿梭物，并已实现高达 13% 的功率转换效率 (η)。自 2016 年以来，铜 (I/II) 配合物因其更正的氧化还原电位而作为第三代氧化还原穿梭物出现。早期铜基 DSSC 的 η 值较低，但迄今为止，由于调节了铜配合物和敏化剂的分子结构，它们的 η 值已达到 13%。在本期展望中，重点介绍了基于铜的 DSSC 的最新发展和前景，以实现超过 15% 的功率转换效率。