The efficiency of two-dimensional Dion–Jacobson-type materials relies on the complex interplay between electronic and lattice dynamics; however, questions remain about the functional role of exciton–phonon interactions. Here we establish the robust polaronic nature of the excitons in these materials at room temperature by combining ultrafast spectroscopy and electronic structure calculations. We show that polaronic distortion is associated with low-frequency (30–60 cm⁻¹) lead iodide octahedral lattice motions. More importantly, we discover how targeted ligand modification of this two-dimensional perovskite structure manipulates exciton–phonon coupling, exciton polaron population and carrier cooling. At high excitation density, stronger exciton–phonon coupling increases the hot-carrier lifetime, forming a hot-phonon bottleneck. Our study provides detailed insight into the exciton–phonon coupling and its role in carrier cooling in two-dimensional perovskites relevant for developing emerging hybrid semiconductor materials with tailored properties.

二维迪翁-雅各布森型材料的效率依赖于电子和晶格动力学之间复杂的相互作用；然而，关于激子-声子相互作用的功能作用仍然存在疑问。在这里，我们通过结合超快光谱和电子结构计算，在室温下建立了这些材料中激子的鲁棒极化性质。我们表明，极化畸变与低频（30-60 cm ^-1 ）碘化铅八面体晶格运动相关。更重要的是，我们发现了这种二维钙钛矿结构的靶向配体修饰如何操纵激子-声子耦合、激子极化子群体和载流子冷却。在高激发密度下，更强的激子-声子耦合会增加热载流子寿命，形成热声子瓶颈。我们的研究提供了对激子-声子耦合及其在二维钙钛矿载流子冷却中的作用的详细见解，这与开发具有定制特性的新兴混合半导体材料相关。