Fabrication of Potassium- and Rubidium-Doped Formamidinium Lead Bromide Nanocrystals for Surface Defect Passivation and Improved Photoluminescence Stability,ACS Applied Electronic Materials

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Fabrication of Potassium- and Rubidium-Doped Formamidinium Lead Bromide Nanocrystals for Surface Defect Passivation and Improved Photoluminescence Stability
ACS Applied Electronic Materials ( IF 4.3 ) Pub Date : 2024-01-04 , DOI: 10.1021/acsaelm.3c01542
Madeeha Tabassum ₁ , Qasim Zia ₂ , Huanqing Ye ₃ , William George Neal ₄ , Sameen Aslam ₅ , Jinshuai Zhang ₆ , Lei Su ₁

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The past decade has seen a rapid development in metal halide perovskite nanocrystals (NCs), which has been witnessed by their potential applications in nanotechnology. The inimitable chemical nature behind their unique photoluminescence characteristics has attracted a growing body of researchers. However, the low intrinsic stability and surface defects of perovskite NCs have hampered their widespread applications. Therefore, numerous techniques such as doping and encapsulation (polymer matrices, silica coating, salt matrix, etc.) have been examined for the surface modification of perovskite NCs and to increase their efficiency and stability. In this study, we demonstrated the self-passivation method for surface defects by introducing potassium (K) or rubidium (Rb) during the colloidal fabrication of NCs, resulting in the much-improved crystallinity, photoluminescence, and improved radiative efficiency. In addition, K-doped NCs showed a long-term colloidal stability of more than 1 month, which indicates the strong bonding between the NCs and the smaller-sized potassium cations (K⁺). We observed the enhancement of the radiative lifetime that can also be explained by the prevention of “Frenkel defects” when K⁺ stays at the interstitial site of the nanocrystal structure. Furthermore, our current findings signify the importance of surface modification techniques using alkali metal ions to reduce the surface traps of perovskite nanocrystals (PeNCs). Comparable developments could be applied to polycrystalline perovskite thin films to reduce the interface trap densities. The findings of this study have several important implications for future light-emitting applications.

中文翻译：

制备钾和铷掺杂的甲脒溴化铅纳米晶，用于表面缺陷钝化和提高光致发光稳定性

过去十年见证了金属卤化物钙钛矿纳米晶体（NC）的快速发展，它们在纳米技术中的潜在应用证明了这一点。其独特的光致发光特性背后独特的化学性质吸引了越来越多的研究人员。然而，钙钛矿 NC 的低本征稳定性和表面缺陷阻碍了其广泛应用。因此，已经研究了许多技术，如掺杂和封装（聚合物基质、二氧化硅涂层、盐基质等）用于钙钛矿 NC 的表面改性并提高其效率和稳定性。在这项研究中，我们通过在 NC 的胶体制造过程中引入钾（K）或铷（Rb）来证明表面缺陷的自钝化方法，从而大大提高了结晶度、光致发光和辐射效率。此外，K 掺杂的 NCs 显示出超过 1 个月的长期胶体稳定性，这表明 NCs 与较小尺寸的钾阳离子（K⁺）之间存在很强的键合。我们观察到辐射寿命的延长，这也可以通过防止 K⁺ 停留在纳米晶体结构的间隙部位的“Frenkel 缺陷”来解释。此外，我们目前的研究结果表明了使用碱金属离子的表面改性技术对减少钙钛矿纳米晶体（PeNCs）表面陷阱的重要性。类似的发展可以应用于多晶钙钛矿薄膜，以降低界面陷阱密度。这项研究的结果对未来的发光应用具有几个重要意义。

更新日期：2024-01-04

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