Lead halide materials have seen a recent surge of interest from the photovoltaics community following the observation of surprisingly high photovoltaic performance, with optoelectronic properties similar to GaAs. This begs the question: What is the limit for the efficiency of these materials? It has been known that under 1-sun illumination the efficiency limit of crystalline silicon is ∼29%, despite the Shockley–Queisser (SQ) limit for its bandgap being ∼33%: the discrepancy is due to strong Auger recombination. In this article, we show that methyl ammonium lead iodide (MAPbI₃) likewise has a larger than expected Auger coefficient. Auger nonradiative recombination decreases the theoretical external luminescence efficiency to ∼95% at open-circuit conditions. The Auger penalty is much reduced at the operating point where the carrier density is less, producing an oddly high fill factor of ∼90.4%. This compensates the Auger penalty and leads to a power conversion efficiency of 30.5%, close to ideal for the MAPbI₃ bandgap.

中文翻译：

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碘化钙钛矿型铅酸太阳能电池的基本效率极限

在观察到令人惊讶的高光伏性能以及与GaAs相似的光电子性能后，卤化铅材料引起了光伏界的关注。这就引出了一个问题：这些材料的效率极限是多少？众所周知，在1阳光照射下，晶体硅的效率极限为〜29％，尽管肖克利-奎塞尔（SQ）的带隙极限为〜33％：差异是由于强烈的俄歇重组引起的。在本文中，我们证明了甲基铵碘化铅（MAPbI ₃）同样比预期的俄歇系数大。在开路条件下，俄歇非辐射复合将理论外部发光效率降低至约95％。在载流子密度较小的工作点上，俄歇罚分被大大降低，产生了高达〜90.4％的奇高填充因子。这补偿了俄歇损失，并导致30.5％的功率转换效率，接近MAPbI ₃带隙的理想状态。