Metal halide perovskites (MHPs) have attracted extensive attention due to their excellent optoelectronic properties. Among them, layered two-dimensional (2D) metal halide materials with special structures have attracted extensive attention due to their superior stability and optoelectronic properties. Here, we report the 2D Ruddlesden–Popper (RP) phase Cs3Cd2Cl7 synthesized by a solvothermal method, and the photoluminescence quantum yields (PLQYs) of the pristine Cs3Cd2Cl7 sample (PLQY ∼ 10%) can be increased to 68 ± 5% through appropriate Sb3+ doping. This should be the highest PLQY of all reported all-inorganic RP-phase Cd-based perovskites so far. Our results indicate that the highly efficient cyan emission can be attributed to the common self-trapped exciton (STE) emission of the triplet states of Cd2+ and Sb3+ induced by strong electron–phonon coupling, and Sb3+:Cs3Cd2Cl7 has excellent structural and spectral stability. This new material should be a promising candidate for optoelectronic applications in the future.
Qilin Wei,Tongtong Kou,Tong Chang,Liang Wang,Xinxin Han,William W. Yu
Ruddlesden−Popper phases Cs2CdCl4 and Cs3Cd2Cl7 are widely used in experimental research of optoelectronics due to their excellent doping matrix properties, but their optoelectronic mechanisms have not been fully explored. This study uses first-principles calculations and experiments to analyze the differences in point defect crystal growth and optoelectronic properties caused by Sb doping of these two materials. Sb tends to replace the position of Cd in both structures. Additional doping energy levels are introduced in the Sb doping of Cs2CdCl4, and the flat band edge increases the local charge density and improves the electron-hole recombination efficiency. The photoluminescence quantum yield (PLQY) of 0.1% Sb:Cs2CdCl4 doping is as high as 79.09%. Molecular dynamics simulations show that the octahedral distortion of [SbCl6]3– in Cs2CdCl4 is highly sensitive to temperature, and the Jahn–Teller distortion causes the formation of self-trapped excitons, which is more conducive to the generation of exciton recombination luminescence. In contrast, Sb doping of Cs3Cd2Cl7 produces a lower PLQY, which can be explained by the more delocalized charge distribution at its band edges and the lower octahedral structural distortion. Sb:Cs2CdCl4 exhibits high-performance X-ray imaging capabilities. This work provides valuable insights and guidance for optimizing Sb-doped Cd-based optoelectronic materials.
危险品化学品经营许可证（带存储）