有機-無機錳鹵化物結構與特性研究

Abstract

有機-無機錳鹵化物作為新興之材料，於雷射、光伏電池、發光二極體等領域具廣泛之應用，因合成方法較容易且具較高量子效率，故近年興起探討其發光機制之研究。有機-無機錳鹵化物之研究正起步，其與發展已久之貴金屬發光材料不同，主要聚焦於分子結構設計與光物理性質之調控。然先前報導之文獻僅研究其基礎之發光特性，無深入探討，且目前眾多研究中提及多種影響量子效率之因素，缺乏統整與連結性之比較，故揭示整合性之通則乃為重要。 本研究採用簡易之溶液法配製三種四面體錳(II)化合物(BTMA)2MnBr4、(PPh4)2MnBr4與(N-BHMTA)2MnBr4，進行同步輻射X光繞射、電子順磁共振光譜、熱重分析、螢光光譜、拉曼光譜等結構與光學鑑定。此類化合物於450 nm光源激發下具綠色放光，其中(PPh4)2MnBr4之量子效率高達93%。另由變溫螢光光譜與拉曼光譜表明此類化合物具相轉變之特性。變壓螢光光譜則可知因晶體壓縮而使晶體場增強造成其光譜紅移。此外本研究亦進行理論計算，探討發光材料與結構之關係，揭示高量子效率(高於80%)與低量子效率(低於40%)之通則，適用於混合錳(II)化合物之結構與量子效率之模型，此將為有機-無機混合金屬鹵化物之發光特性提供更全面之瞭解。藉上述結構分析與光譜探討以建立優化方法與增加材料之應用價值。

In recent years, organic-inorganic hybrid manganese halide has emerged as a new material with a wide range of applications in the fields of lasers, photovoltaics, and light-emitting diodes. Its synthesis method is relatively easy and has high quantum efficiency; as a result, more work has been done on its luminescence mechanism. Different from the previous metal luminescent materials, the research of organic-inorganic manganese hybrid halides is just starting, mainly in molecular structure design and the regulation of photophysical properties. However, the previously reported literature only focuses on its basic luminescence characteristics without further in-depth discussion, and many current studies mention a variety of factors that affect quantum efficiency and lack connectivity comparisons. Therefore, a general rule of the relationship between structure and quantum efficiency is necessary. In this study, three tetrahedral manganese(II) compounds, (BTMA)2MnBr4, (PPh4)2MnBr4, and (N-BHMTA)2MnBr4 were prepared using a simple solution method, and synchrotron radiation X-ray diffraction (XRD), electron paramagnetic resonance (EPR), thermogravimetric analysis (TGA), photoluminescence (PL) and Raman spectroscopy were performed in order to study optical properties. These compounds exhibit bright green phosphorescence when excited by a 450 nm light source and the quantum efficiency of (PPh4)2MnBr4 is up to 93%. Temperature-dependent photoluminescence and Raman spectra indicate that these compounds have phase transitions. The pressure-dependent photoluminescence spectra show that the crystal field is enhanced because of crystal compression, leading to the spectral redshift. In this study, theoretical calculations were also used to investigate the relationship between luminescent materials and structures. We propose a general rule applicable to the structure and quantum efficiency of organic-inorganic hybrid manganese halides. This investigation provides deep insights into the luminescent properties of hybrid manganese halides and finds an optimized way to increase the application of materials through the analysis mentioned above and the spectroscopic mechanism.