Over the past decade, the world has witnessed tremendous achievement in power conversion efficiency (PCE) enhancement for Pb-perovskite solar cells (PSCs). However, spectral loss limits the performance, which can be overcome with tandem solar cells (TSCs) and hence with excellent optoelectronic properties and bandgap tunability Pb-perovskites have been widely used as front/rear sub-cells in TSCs, where variable bandgap sub-cells can utilize maximum spectral radiations. Though the operational instability issue has been well controlled by structural optimizations, yet Pb toxicity is a major challenge in commercializing Pb-PSCs. To resolve the issue of toxicity, Pb-free perovskites have gained immense consideration, especially Sn²⁺ having similar physical properties to Pb²⁺ and non-toxic feature of Sn²⁺, Ge²⁺, Bi³⁺, or Sb³⁺ perovskites. In TSCs, the wide bandgap (WBG ≥ 1.6 eV) sub-cell plays a critical role in harnessing shorter wavelength photons and is responsible to achieve high Voc. To nurture Pb-free all-PTSC technology, it is urgent to develop high-performance Pb-free WBG PSCs. To understand the seriousness herein, this review focus on the existing challenges in Pb-free WBG PSCs and discuss new strategies that have been implemented with state-of the art fabrication techniques to enhance device performance. By discussing the issues of trap densities, defects formation, bandgap mismatching, V_oc deficits, and poor stability, we focused on the strategies to overcome these issues through compositional engineering, and defect passivation via additive and interfacial engineering. In conclusive remarks, we discussed our viewpoint with innovative ideas that can be applied to collectively focus on this area to achieve high-performance Pb-free WBG PSCs.

在过去的十年中，世界见证了铅钙钛矿太阳能电池（PSC）在提高功率转换效率（PCE）方面取得的巨大成就。然而，光谱损失限制了性能，这可以通过串联太阳能电池 (TSC) 克服，因此具有优异的光电性能和带隙可调性 Pb-钙钛矿已被广泛用作 TSC 中的前/后子电池，其中可变带隙子电池细胞可以利用最大的光谱辐射。尽管操作不稳定性问题已通过结构优化得到很好的控制，但铅毒性是 Pb-PSC 商业化的主要挑战。为了解决毒性问题，无铅钙钛矿得到了广泛的考虑，特别是具有与 Pb ²⁺相似物理性质的Sn ^{2+Sn 2+}、Ge ²⁺、Bi ³⁺或Sb ³⁺钙钛矿的无毒特性。在 TSC 中，宽带隙 (WBG ≥ 1.6 eV) 子电池在利用较短波长的光子方面发挥着关键作用，并负责实现高 Voc。为了培育无铅全PTSC技术，开发高性能无铅WBG PSC是当务之急。为了理解此处的严重性，本综述重点关注无铅 WBG PSC 中的现有挑战，并讨论已采用最先进的制造技术实施以提高器件性能的新策略。通过讨论陷阱密度、缺陷形成、带隙失配、V _oc缺陷和稳定性差，我们专注于通过成分工程克服这些问题的策略，以及通过添加剂和界面工程的缺陷钝化。在总结性评论中，我们讨论了我们的观点，提出了可以应用于共同关注这一领域以实现高性能无铅 WBG PSC 的创新想法。