Dakshinamurthy Athrey C, Sudakar C
Multifunctional Materials Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India.
J Phys Chem Lett. 2022 Jan 20;13(2):433-439. doi: 10.1021/acs.jpclett.1c03862. Epub 2022 Jan 6.
Sublattice distortion resulting from alloying compositionally distinct double perovskites is shown to influence photoluminescence emission in CsAgNaBiCl (0 < < 1). The end members show negligible photoluminescence, whereas interestingly the alloys exhibit broad photoluminescence. These emissions are attributed to self-trapped excitons (STE) resulting from sublattice distortions arising due to the mismatch in [AgCl] and [BiCl] octahedra. Change in sublattice distortions plays significant role in the formation and recombination of STEs. The STE emission intensity and quantum yield greatly depend on , with highest intensity observed for = 0.75, consistent with a large change in sublattice found at this . Variation in photoluminescence properties with composition follows a similar trend as that of bandgap and phonon vibrational changes observed due to sublattice distortion. Temperature-dependent phonon vibrations and photoluminescence studies reveal a giant electron-phonon coupling. A strong synergy between STE emissions, electron-phonon coupling, bandgap, and phonon vibrations in double perovskites with sublattice distortions is demonstrated.
合金化成分不同的双钙钛矿所导致的亚晶格畸变被证明会影响CsAgNaBiCl（0 << 1）中的光致发光发射。端元显示出可忽略不计的光致发光，而有趣的是，合金表现出宽的光致发光。这些发射归因于[AgCl]和[BiCl]八面体失配引起的亚晶格畸变所产生的自陷激子（STE）。亚晶格畸变的变化在STE的形成和复合中起重要作用。STE发射强度和量子产率很大程度上取决于，在 = 0.75时观察到最高强度，这与此时发现的亚晶格的大变化一致。光致发光性质随成分的变化遵循与由于亚晶格畸变观察到的带隙和声子振动变化类似的趋势。温度依赖的声子振动和光致发光研究揭示了巨大的电子 - 声子耦合。证明了具有亚晶格畸变的双钙钛矿中STE发射、电子 - 声子耦合、带隙和声子振动之间的强协同作用。
