Herein, the emission characteristics of diammonium N,N,N′,N′-tetramethyl-1,4-phenylenediammonium (TMPDA) are investigated based on lead iodide (TMPDA)PbI₄ perovskite single crystals correlated with the localized lattice vibrations. Dual emission characteristics are ascribed to the existence of free exciton and bound exciton. The photoluminescence spectra as a function of excitation power and temperature show that structural distortion and exciton-phonon coupling impact emission characteristics substantially. The coupling strength between excitons and phonons in (TMPDA)PbI₄ is estimated as γ_ac = 308.96 µeV and γ_LO = 62.3 meV, which is much higher than inorganic semiconductors. Further, bound exciton band recombination is significantly suppressed at lower temperatures due to increased localization of carriers. Specific heat deviation from the Dulong–Petit law indicates strong coupling in the lattice. The Debye-Einstein model reveals multiple low-energy localized independent vibrations, leading to phonon coupling with bound excitons. This interplay, along with Bosonic features, significantly influences emission properties. Further, it is observed that photocurrent as a function of the incident intensity follows a law ∝ I₀^α with α = 0.54, attributed to substantial bimolecular recombination of carriers. The findings of the study provide an in-depth understanding of emission characteristics, lattice distortion, and interplay of electron-phonon coupling in DJ phase 2D perovskite system.

中文翻译：

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二维 Dion-Jacobson 钙钛矿中的局部振动和结合激子介导的发射


在此，基于碘化铅 （TMPDA）PbI₄ 钙钛矿单晶与局部晶格振动相关，研究了二铵 N，N，N′，N′-四甲基-1,4-苯二铵 （TMPDA） 的发射特性。双重发射特性归因于自由激子和结合激子的存在。光致发光光谱作为激发功率和温度的函数表明，结构畸变和激子-声子耦合对发射特性有很大影响。（TMPDA）PbI₄ 中激子和声子之间的耦合强度估计为 γ_ac = 308.96 μeV 和 γ_LO = 62.3 meV，远高于无机半导体。此外，由于载体定位的增加，结合的激子带复合在较低温度下被显着抑制。比热与 Dulong-Petit 定律的偏差表明晶格中有很强的耦合。Debye-Einstein 模型揭示了多个低能量的局部独立振动，导致声子与结合激子耦合。这种相互作用以及 Bosonic 特征会显著影响发射特性。此外，据观察，作为入射强度的函数∝光电流遵循 I₀^α 的定律，其中 α = 0.54，这归因于载流子的大量双分子复合。研究结果提供了对 DJ 相 2D 钙钛矿系统中发射特性、晶格失真和电子-声子耦合相互作用的深入理解。