Lead-free perovskite solar cell (PSC) is the direction of future development of PSCs due to its reduced toxicity. However, the power conversion efficiency (PCE) of the lead-free PSCs is still lagging behind their lead-based counterparts, which hinders their further application. Multi-absorber approach can effectively overcome this problem as it allows the maximum utilization of solar spectrum. Therefore, in this study a novel lead-free MASnI₃/CsGeI₃ heterojunction structure is proposed to boost the performance of PSCs based on single CsGeI₃ absorption layer. The critical device parameters including absorber thickness, defect density, doping concentration, and back contact work function are studied and optimized using the numerical software SCAPS-1D. Under optimized conditions, PSCs based on Sn/Ge bilayer structure yield a considerable PCE of 16.15%, significantly higher than the single CsGeI₃ based PSCs (optimized PCE of 7.43%) with higher thermal stability. The simulation results indicate a huge potential of the proposed multi-absorber heterojunction structure for highly efficient lead-free PSCs, which will contribute to achieving clean and sustainable energy in the future.

中文翻译：

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通过器件模拟提高基于多吸收剂 MASnI3/CsGeI3 异质结的无铅钙钛矿太阳能电池的性能

无铅钙钛矿太阳能电池（PSC）因其毒性降低而成为PSC未来发展的方向。然而，无铅PSC的功率转换效率（PCE）仍然落后于铅基PSC，这阻碍了其进一步应用。多吸收器方法可以有效克服这个问题，因为它可以最大限度地利用太阳光谱。因此，在本研究中，提出了一种新型无铅MASnI ₃ /CsGeI ₃异质结结构，以提高基于单CsGeI ₃吸收层的PSC的性能。使用数值软件SCAPS-1D研究并优化了吸收体厚度、缺陷密度、掺杂浓度和背接触功函数等关键器件参数。在优化条件下，基于Sn/Ge双层结构的PSC产生了高达16.15%的可观PCE，显着高于基于单一CsGeI _{3 的}PSC（优化PCE为7.43%），并且具有更高的热稳定性。模拟结果表明，所提出的多吸收剂异质结结构在高效无铅PSC方面具有巨大潜力，这将有助于在未来实现清洁和可持续能源。