Bi3+/Te4+ co-doped Cs2SnCl6 with dual emission spectrum (i.e., 450 and 575 nm) was achieved by a modified solution method, which can overcome the phase separation in the previous method for Cs2SnCl6 crystal growth. The two emission peaks arising from the two dopants Bi3+ and Te4+ have distinct photoluminescence (PL) lifetimes. Thus, the control of dopant ratio or PL delay time will regulate the PL intensity ratio between 450 and 575 nm peaks leading to adjustable emission color. The energy transfer between the two emission centers, which is confirmed by the optical spectra and PL lifetime, has a critical distance around 7.8 nm with a maximum of 50% transfer efficiency. The Bi3+/Te4+ co-doped Cs2SnCl6 with superior stability in water and aqua regia was fabricated into a single-phase white light-emitting diode. In the meantime, various luminescent heterostructures were obtained by epitaxial Cs2SnCl6 crystal growth with different dopants, which can broaden the study of composition engineering in halide perovskites.

Two hybrid organic−inorganic metal halides with room-temperature phosphorescence (RTP) have been designed and synthesized. The aromatic organic ligands in the hybrid structures give rise to the phosphorescent property, while the rigid inorganic frameworks in the hybrid structures enhance the RTP efficiency. Pb 2 (PLA)(H 2 O) 2 Br 2 (PLA, 1,4-phenylenediacetic acid) shows the anti-Kasha's rule RTP, which has been rarely reported before. The twisted intramolecular charge transfer (TICT) in a flexible PLA ligand might be the origination of the anti-Kasha's rule RTP according to the photoluminescence study under the variables of temperature, excitation wavelength, and ligands. A method that combined the calculations from Platon and CrystalExplorer has been built to analyze the packing mode and interaction of the ligands. The compact face-to-face packing of aromatic ligands leads to the highest RTP efficiency in Pb 4 (TPA) 3 Br 2 . Due to the strong covalent bonding, Pb 4 (TPA) 3 Br 2 exhibits superior thermal stability and water resistance, which can serve as an efficient LED underwater.

The authors Yang-Peng Lin and Bing Xia contributed equally.

No abstract

No abstract