Dai Jiaqi, Tang Wenchao, Li Tingfeng, Xu Cuiping, Zhao Min, Ji Peiqi, Li Xiaolei, Zhang Fengming, Cai Hongling, Wu Xiaoshan
National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing 210093, China.
Institute of Materials Engineering, Nantong 226019, China.
Nanomaterials (Basel). 2025 Jun 24;15(13):981. doi: 10.3390/nano15130981.
In this study, we investigate the influence of the halogen elements bromine (Br) and chlorine (Cl) on iodine defect properties primarily in FAPbI through first-principles calculations, aiming to understand the effect of high defect densities on the efficiency of organic-inorganic hybrid perovskite cells. The results indicate that Br and Cl interstitials minimally alter the overall band structure of FAPbI but significantly modify the defect energy levels. Br and Cl interstitials, with defect states closer to the valence band and lower formation energies, effectively convert deep-level traps induced by iodine interstitials (I) into shallow-level traps. This conversion enhances carrier transport by reducing non-radiative recombination while preserving light absorption efficiency. Excess Br/Cl co-doping in FAPbI synthesis thereby suppresses non-radiative recombination and mitigates the detrimental effects of iodide-related defects.
在本研究中，我们通过第一性原理计算，主要研究了卤素元素溴（Br）和氯（Cl）对FAPbI中碘缺陷性质的影响，旨在了解高缺陷密度对有机-无机杂化钙钛矿电池效率的影响。结果表明，Br和Cl间隙原子对FAPbI的整体能带结构影响极小，但能显著改变缺陷能级。Br和Cl间隙原子的缺陷态更接近价带且形成能较低，能有效地将碘间隙原子（I）诱导的深能级陷阱转化为浅能级陷阱。这种转化通过减少非辐射复合来增强载流子传输，同时保持光吸收效率。因此，在FAPbI合成过程中过量的Br/Cl共掺杂可抑制非辐射复合，并减轻碘化物相关缺陷的有害影响。
