Hsiao Yuan-Wen, Song Jyun-You, Wu Hsuan-Ta, Leu Ching-Chich, Shih Chuan-Feng
Department of Electrical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Department and Institute of Electrical Engineering, Minghsin University of Science and Technology, Hsinchu 30401, Taiwan.
Nanomaterials (Basel). 2022 Jan 3;12(1):157. doi: 10.3390/nano12010157.
This study investigates the effects of Rb doping on the Rb-formamidinium-methylammonium-PbI based perovskite photodetectors. Rb was incorporated in the perovskite films with different contents, and the corresponding photo-response properties were studied. Doping of few Rb (~2.5%) was found to greatly increase the grain size and the absorbance of the perovskite. However, when the Rb content was greater than 2.5%, clustering of the Rb-rich phases emerged, the band gap decreased, and additional absorption band edge was found. The excess Rb-rich phases were the main cause that degraded the performance of the photodetectors. By space charge limit current analyses, the Rb was found to passivate the defects in the perovskite, lowering the leakage current and reducing the trap densities of carriers. This fact was used to explain the increase in the detectivity. To clarify the effect of Rb, the photovoltaic properties were measured. Similarly, h perovskite with 2.5% Rb doping increased the short-circuit current, revealing the decline of the internal defects. The 2.5% Rb doped photodetector showed the best performance with responsivity of 0.28 AW and ~50% quantum efficiency. Detectivity as high as 4.6 × 10 Jones was obtained, owing to the improved crystallinity and reduced defects.
本研究考察了铷（Rb）掺杂对基于铷-甲脒-甲基铵-碘化铅（Rb-甲脒-甲基铵-PbI）的钙钛矿型光电探测器的影响。将不同含量的铷掺入钙钛矿薄膜中，并研究了相应的光响应特性。发现少量铷（约2.5%）的掺杂能显著增大钙钛矿的晶粒尺寸和吸光度。然而，当铷含量大于2.5%时，出现了富铷相的聚集，带隙减小，并发现了额外的吸收带边。过量的富铷相是导致光电探测器性能下降的主要原因。通过空间电荷限制电流分析，发现铷能钝化钙钛矿中的缺陷，降低漏电流并减少载流子陷阱密度。这一事实被用来解释探测率的提高。为了阐明铷的作用，测量了光伏性能。同样，2.5%铷掺杂的钙钛矿提高了短路电流，表明内部缺陷减少。2.5%铷掺杂的光电探测器表现出最佳性能，响应度为0.28 A/W，量子效率约为50%。由于结晶度提高和缺陷减少，获得了高达4.6×10琼斯的探测率。
