Organic–inorganic hybrid metal halides have become enormously important in optoelectronics, sensing, photosensitization, etc. In this study, we report a structural transition from a staircase configuration to a cubane configuration in Cu(I) iodide-based polymers influenced by the coordination behavior of two different π*-acceptor ligands. The staircase polymer structure, coordinated with 3-cyanopyridine, demonstrates efficient thermally activated delayed fluorescence from (metal+halide)-to-ligand charge transfer [^1/3(M+X)LCT] states, with a singlet–triplet energy splitting of ∼9 meV. Conversely, upon replacement of the cyano with an amino group at the same position, a one-dimensional polymeric structure of Cu₄I₄ cubane-type clusters is formed, which shows strong cluster-centered (³CC) orange emission at room temperature. Temperature-dependent photoluminescence studies indicate that the ³CC state behaves as a self-trapped excitonic state with significant exciton–phonon coupling having a Huang–Rhys factor of 58.6. Additionally, we report this cubane-type cluster polymer acts as an efficient nonlinear optical material showing third harmonic generation with a χ⁽³⁾ value of 1.32 × 10^–18 m² V^–2 and a laser-induced damage threshold of 25.87 GW/cm².

中文翻译：

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通过配体工程控制 Cu（I） 碘化物基聚合物中的三重态捕获途径和非线性光学特性


有机-无机杂化金属卤化物在光电子学、传感、光敏化等方面变得非常重要。在这项研究中，我们报道了 Cu（I） 碘化物基聚合物中从阶梯构型到立方烷构型的结构转变，受两种不同 π*-受体配体的配位行为的影响。与 3-氰基吡啶配位的阶梯聚合物结构表现出从（金属 + 卤化物）到配体电荷转移 [^1/3（M+X）LCT] 状态的高效热激活延迟荧光，单重态-三重态能量分裂为 ∼9 meV。相反，当在同一位置用氨基取代氰基时，会形成 Cu₄I₄ 立方烷型团簇的一维聚合物结构，在室温下表现出强烈的团簇中心 （³CC） 橙色发射。温度依赖性光致发光研究表明，³CC 态表现为自捕获激子态，具有显著的激子-声子耦合，Huang-Rhys 因子为 58.6。此外，我们报道了这种立方烷型团簇聚合物作为一种高效的非线性光学材料，显示出 χ^（3） 值为 1.32 × 10^–18 m² V^–2 和 25.87 GW/cm² 激光诱导损伤阈值的三次谐波产生。