Perovskite solar cells (PSCs) have celebrated a decade of investigation as a promising photovoltaic technology. However, they contain lead, so inorganic lead-free PSCs can be designed as green and clean energy sources. To overcome the current obstacles in lead-free PSCs, the stability and performance gap should be minimized. The drift-diffusion simulation model is a conducive way to understand the working mechanism in a thin-film solar cell. Here we adopted a computational approach to design and investigate the performance of CsSn_0.5Ge_0.5I₃ as a light harvester. We optimize the thickness of the perovskite, for its use in an inverted planar structure (FTO/PCBM/CsSn_0.5Ge_0.5I₃/Spiro-OMeTAD/Au). Furthermore, cerium oxide (CeO_x) and PTAA are used as alternative electron and hole transport layers, respectively. We studied the effect of trap density in the bulk CsSn_0.5Ge_0.5I₃ and its impact on performance, recombination rate, and diffusion length. The open-circuit voltage (V_oc) showed a significant improvement and the correlation with the trap density at the interface layers is established. We noted that the defect density at the perovskite/hole selective layer interface has a profound impact on the performance of lead-free PSCs as compared to the electron selective layer/perovskite interface. After optimizing defect parameters, the lead-free PSC can deliver a PCE of 24.20%, with V_oc = 1170 mV, J_sc = 25.80 mA cm⁻², and FF = 80.33%. Our findings provide access guidelines and pave the way for lead-free PSCs based on the Sn–Ge combination to approach their limit.

中文翻译：

---

通过解锁复合通道来利用无铅 Sn-Ge 基钙钛矿太阳能电池的潜力

钙钛矿太阳能电池 (PSC) 作为一种很有前途的光伏技术，已经庆祝了十年的研究。然而，它们含有铅，因此无机无铅 PSC 可以设计为绿色清洁能源。为了克服目前无铅 PSC 的障碍，稳定性和性能差距应该最小化。漂移扩散模拟模型是了解薄膜太阳能电池工作机制的有益方法。在这里，我们采用计算方法来设计和研究 CsSn _0.5 Ge _0.5 I ₃作为光收集器的性能。我们优化了钙钛矿的厚度，将其用于倒置平面结构 (FTO/PCBM/CsSn _0.5 Ge _0.5 I ₃/Spiro-OMeTAD/Au)。此外，氧化铈 (CeO _x ) 和 PTAA 分别用作替代电子和空穴传输层。我们研究了 CsSn _0.5 Ge _0.5 I ₃体中陷阱密度的影响及其对性能、复合率和扩散长度的影响。开路电压 ( V _oc) 显示出显着改善，并建立了与界面层陷阱密度的相关性。我们注意到，与电子选择层/钙钛矿界面相比，钙钛矿/空穴选择层界面的缺陷密度对无铅 PSC 的性能有深远的影响。优化缺陷参数后，无铅 PSC 可提供 24.20% 的 PCE，V _oc = 1170 mV，J _sc = 25.80 mA cm ^-2，FF = 80.33%。我们的研究结果提供了获取指南，并为基于 Sn-Ge 组合的无铅 PSC 接近其极限铺平了道路。