Organic–inorganic hybrid perovskites (OIHP) are developing rapidly as high-performance semiconductors for solid-state solar cells and light emitting devices. Recently, lead-halide two-dimensional (2D) OIHP were found to present bright broadband visible emission, thus, highlighting their potential as single component white-light (WL) emitters. This contribution deals with the preparation of a new Cd-based 2D hybrid perovskite, of the chemical formula (C₆H₁₁NH₃)₂CdBr₄ (abbreviated as compound 1), of which structural and optical properties have been studied and analyzed. Room temperature optical absorption (OA) measurements, performed on spin-coated film of compound 1, revealed a sharp excitonic absorption peak at 3.24 eV, and a large exciton binding energy of 377 meV, estimated from low temperature OA spectrum. Upon 325 nm irradiation, compound 1 showed a very broadband WL emission consisting of one peak at 2.94 eV, attributed to exciton confined in the [CdBr₄]^2– inorganic layers, and a second peak at 2.53 eV resulting from the cyclohexylammonium cations emission. Temperature dependence of PL spectra evidenced anomalous behavior accompanied by singularities around 50 and 150 K in the integrated intensity, the full width at half-maximum and the PL peaks positions. These singularities have been traced back to structural phase transitions, from temperature dependence powder and single crystal X-ray diffraction investigations, from which strong correlations had emerged between the structural distortion of the CdBr₆ pseudo-octahedron and the broadening characteristics of the WL emission band. These hitherto unrecognized properties turn this and similar OIHP into perspective candidates for potential applications as WL-emitting diodes.

中文翻译：

---

新的基于镉的二维杂化钙钛矿中的宽带发射

有机-无机杂化钙钛矿（OIHP）作为用于固态太阳能电池和发光器件的高性能半导体，正在迅速发展。最近，发现卤化铅二维（2D）OIHP呈现明亮的宽带可见光发射，因此，突出了它们作为单组分白光（WL）发射器的潜力。该贡献涉及化学式（C ₆ H ₁₁ NH ₃）₂ CdBr ₄（缩写为化合物1）的新的基于Cd的二维杂化钙钛矿的制备，已经对其结构和光学性质进行了研究和分析。在化合物1的旋涂膜上进行室温光吸收（OA）测量，根据低温OA光谱估计，在3.24 eV处显示出一个尖锐的激子吸收峰，在377 meV处有一个大的激子结合能。在325 nm的辐射下，化合物1显示出非常宽的WL发射，该发射由2.94 eV处的一个峰组成，这归因于[CdBr ₄ ] ^2–无机层，以及由于环己基铵阳离子发射而在2.53 eV处出现的第二个峰。PL光谱的温度依赖性证明了异常行为，并伴随着积分强度，半峰全宽和PL峰位置的奇异性，积分强度在50和150 K附近。这些奇异性可追溯到结构相变，从温度依赖性粉末和单晶X射线衍射研究开始，由此发现CdBr ₆伪八面体的结构变形与WL发射谱带的展宽特性之间具有很强的相关性。。这些迄今无法识别的特性将这种OIHP和类似的OIHP变成了潜在的潜在候选物，可用作WL发射二极管。