Traditional inorganic semiconductors can be electronically doped with high precision. Conversely, there is still conjecture regarding the assessment of the electronic doping density in metal-halide perovskites, not to mention of a control thereof. This paper presents a multifaceted approach to determine the electronic doping density for a range of different lead-halide perovskite systems. Optical and electrical characterization techniques, comprising intensity-dependent and transient photoluminescence, AC Hall effect, transfer-length-methods, and charge extraction measurements were instrumental in quantifying an upper limit for the doping density. The obtained values are subsequently compared to the electrode charge per cell volume under short-circuit conditions ([Formula: see text]), which amounts to roughly 1016 cm−3. This figure of merit represents the critical limit below which doping-induced charges do not influence the device performance. The experimental results consistently demonstrate that the doping density is below this critical threshold (∼1012 cm−3, which means ≪ [Formula: see text]) for all common lead-based metal-halide perovskites. Nevertheless, although the density of doping-induced charges is too low to redistribute the built-in voltage in the perovskite active layer, mobile ions are present in sufficient quantities to create space-charge-regions in the active layer, reminiscent of doped pn-junctions. These results are well supported by drift–diffusion simulations, which confirm that the device performance is not affected by such low doping densities.

中文翻译：

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揭示钙钛矿太阳能电池中的掺杂密度及其对器件性能的影响

传统的无机半导体可以进行高精度电子掺杂。相反，关于金属卤化物钙钛矿中电子掺杂密度的评估仍然存在猜想，更不用说对其进行控制了。本文提出了一种多方面的方法来确定一系列不同的卤化铅钙钛矿系统的电子掺杂密度。包括强度依赖性和瞬态光致发光、交流霍尔效应、转移长度法和电荷提取测量在内的光学和电气表征技术有助于量化掺杂密度的上限。随后将获得的值与短路条件下每电池体积的电极电荷进行比较（[公式：见文本]），大约为 1016厘米−3. 该品质因数表示临界限值，低于该临界限值时掺杂引起的电荷不会影响器件性能。实验结果一致表明掺杂密度低于该临界阈值（~1012厘米−3，这意味着 ≪ [公式：见文本]) 对于所有常见的铅基金属卤化物钙钛矿。然而，尽管掺杂诱导电荷的密度太低而无法重新分布钙钛矿活性层中的内置电压，但移动离子的数量足以在活性层中产生空间电荷区，让人联想到掺杂的 pn-路口。这些结果得到了漂移扩散模拟的很好支持，证实了器件性能不受如此低的掺杂密度的影响。