Wechprasit Tirapat, Bootchanont Atipong, Infahsaeng Yingyot, Wongjom Poramed, Wannapaiboon Suttipong, Kaewprajak Anusit, Kumnorkaew Pisist, Sailuam Wutthigrai, Saenrang Wittawat, Pecharapa Wisanu, Maiaugree Wasan
Division of Physics, Faculty of Science and Technology, Thammasat University, Bangkok , 12120, Pathum Thani, Thailand.
Division of Physics, Faculty of Science and Technology, Rajamagala University of Technology, Thanyaburi, 12110, Pathum Thani, Thailand.
Sci Rep. 2025 May 26;15(1):18351. doi: 10.1038/s41598-025-02226-1.
A thorough investigation of perovskite structures formed through doping is essential for advancing the efficiency and stability of perovskite solar cells. In this study, Bi-doped FAPbI perovskite films with varying Bi concentrations (0.5-2%) were fabricated using a spin-coating technique on ITO glass substrates. Then the films' phase structure, local structure, and optical characteristics were analyzed. X-ray diffraction (XRD) analysis revealed that the pristine FAPbI film exhibited both hexagonal and cubic phases, indicating structural instability. In contrast, Bi-doped FAPbI films predominantly displayed a cubic perovskite structure, with a notable reduction in the XRD peak intensity corresponding to the hexagonal phase. UV-Vis spectroscopy showed that the undoped FAPbI film had an absorption edge in the visible-near infrared range, while Bi-doping caused a redshift, indicating a reduction in the optical band gap. The calculated results show that optical band gaps decrease with increasing Bi, from a value of 1.49 (pure) to 1.43 (2% Bi) eV. X-ray absorption near edge structure (XANES) analysis confirmed the oxidation states of Pb and Bi ions across all samples, with Bi ions replacing Pb in the local structure. Photoluminescence (PL) measurements revealed an increased PL intensity with 1% Bi doping (7 × 10) compared with pristine FAPbI (4.7 × 10), suggesting a reduction in carrier recombination. These findings demonstrate the potential of Bi-doping to stabilize perovskite structures with improved optoelectronic properties.
深入研究通过掺杂形成的钙钛矿结构对于提高钙钛矿太阳能电池的效率和稳定性至关重要。在本研究中，采用旋涂技术在ITO玻璃基板上制备了不同铋浓度（0.5 - 2%）的铋掺杂FAPbI钙钛矿薄膜。然后对薄膜的相结构、局部结构和光学特性进行了分析。X射线衍射（XRD）分析表明，原始的FAPbI薄膜呈现六方相和立方相，这表明结构不稳定。相比之下，铋掺杂的FAPbI薄膜主要呈现立方钙钛矿结构，对应六方相的XRD峰强度显著降低。紫外-可见光谱表明，未掺杂的FAPbI薄膜在可见光-近红外范围内有吸收边，而铋掺杂导致红移，表明光学带隙减小。计算结果表明，光学带隙随着铋含量的增加而减小，从纯FAPbI的1.49 eV降至2%铋掺杂时的1.43 eV。X射线吸收近边结构（XANES）分析证实了所有样品中Pb和Bi离子的氧化态，在局部结构中Bi离子取代了Pb。光致发光（PL）测量表明，与原始FAPbI（4.7×10）相比，1%铋掺杂时PL强度增加（7×10），这表明载流子复合减少。这些发现证明了铋掺杂在稳定钙钛矿结构并改善其光电性能方面的潜力。
