Riaz Muhammad Asad, Zahid Usman, Mukhtar Maria, Khalid Muhammad Adnan, Mubeen Muhammad, Iqbal Azhar
Department of Chemistry, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
J Fluoresc. 2025 Jan 9. doi: 10.1007/s10895-024-04094-w.
From synthesis to application, there are always certain interactions between the polar solvents and perovskite nanocrystals (NCs). To explain the effect of solvent polarity especially on the photoluminescence (PL) properties of NCs is highly desirable, especially for sensing applications. Herein We have synthesized the methylammonium lead mixed halides (MAPbClBr, where n = 0, 0.5, 1, 1.5) perovskite nanocrystals (NCs) at room temperature by using ligand-assisted re-precipitation (LARP) method, by employing mercaptoacetic acid (MAA) as a capping ligand. Different techniques have been employed to get information regarding the structural and optical properties of the synthesized material. Powder X-ray diffraction (PXRD) confirms the orthorhombic crystal structure of the MAPbClBr perovskite NCs. FT-IR (Fourier-transform infrared) analysis confirms the successful interaction of capping ligands with NCs. By increasing MABr precursor concentration during the synthesis of perovskite NCs, a red shift in the UV-Vis absorption and PL spectra has been observed. The steady-state photoluminescence (SSPL) and time-resolved photoluminescence (TRPL) techniques suggested that these perovskite NCs exhibit tunable PL relative to the substitution of Cl with Br in NCs. The comparative PL studies in non-polar (benzene) and polar (tetrahydrofuran (THF)) revealed that the PL properties are highly sensitive and selective toward the solvent chosen. All synthesized NCs possess longer PL lifetime in benzene than in THF. Relatively, perovskite NCs synthesized with 0.166 mM MABr precursor concentration show a longer PL lifetime (6.51 ns in benzene) as compared to other MABr concentrations. These studies not only propose that by controlling precursors concentration, one can synthesize NCs having tunable PL with a longer radiative PL lifetime, but also provide a comparative understanding of PL dynamics of NCs in different solvents.
从合成到应用，极性溶剂与钙钛矿纳米晶体（NCs）之间总是存在一定的相互作用。尤其对于传感应用而言，非常有必要解释溶剂极性对纳米晶体光致发光（PL）特性的影响。在此，我们通过配体辅助再沉淀（LARP）方法，以巯基乙酸（MAA）作为封端配体，在室温下合成了甲基铵铅混合卤化物（MAPbClBr，其中n = 0、0.5、1、1.5）钙钛矿纳米晶体（NCs）。已采用不同技术获取有关合成材料结构和光学性质的信息。粉末X射线衍射（PXRD）证实了MAPbClBr钙钛矿纳米晶体的正交晶体结构。傅里叶变换红外光谱（FT-IR）分析证实了封端配体与纳米晶体的成功相互作用。在钙钛矿纳米晶体的合成过程中增加MABr前体浓度时，观察到紫外-可见吸收光谱和光致发光光谱发生红移。稳态光致发光（SSPL）和时间分辨光致发光（TRPL）技术表明，相对于纳米晶体中Cl被Br取代的情况，这些钙钛矿纳米晶体表现出可调谐的光致发光。在非极性（苯）和极性（四氢呋喃（THF））溶剂中的对比光致发光研究表明，光致发光特性对所选溶剂高度敏感且具有选择性。所有合成的纳米晶体在苯中的光致发光寿命比在THF中更长。相对而言，与其他MABr浓度相比，用0.166 mM MABr前体浓度合成的钙钛矿纳米晶体在苯中的光致发光寿命更长（6.51 ns）。这些研究不仅表明通过控制前体浓度，可以合成具有可调谐光致发光且具有更长辐射光致发光寿命的纳米晶体，还提供了对不同溶剂中纳米晶体光致发光动力学的对比理解。
