- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
On the Mechanism for the Extremely Efficient Sensitization of Yb3+ Luminescence in CsPbCl3 Nanocrystals
摘要： Rare earth (RE3+) doped inorganic CsPbX3 (X=Cl or Cl/Br) nanocrystals have been presented as promising materials for applications in solar-energy-conversion technology. An extremely efficient sensitization of Yb3+ luminescence in CsPbCl3 nanoparticles (NCs) was very recently demonstrated where quantum cutting is responsible for photoluminescence quantum yields over 100% (T. J. Milstein, et al., Nano Letters 2018, 18, 3792). In the present work, based on cubic phase of inorganic perovskite, we seek atom-level-insight into the basic mechanisms behind these observations in order to boost the further development of RE3+ doped CsPbX3 NCs for optoelectronics. In our calculations of cubic crystal structure, we do not find any energy level formed in the middle of the band gap, which disfavors a mechanism of step-wise energy transfer from the perovskite host to two Yb3+ ions. Our work indicates that the configuration with 'right-angle' Yb3+-VPb-Yb3+ couple are most likely to form in Yb3+-doped CsPbCl3. Associated with this 'right-angle' couple, the 'right-angle' Pb atom with trapped excited states would localize the photogenerated electrons and could act as the energy donor in a quantum cutting process, which achieves simultaneous sensitization of two neighboring Yb3+ ions.
关键词： Quantum cutting,Ytterbium-Doped inorganic perovskite,density function theory (DFT)
更新于2025-09-23 15:22:29
-
Study the electronic properties and magnetization of rutile polymorph CoxTi1-xO2 super cell at various cobalt (Co) concentrations using first principle calculation
摘要： First principle calculation has been performed to study the electronic properties and magnetization of CoxTi1-xO2 at different cobalt concentration. Equilibrium lattice constant of CoxTi1-xO2 at 0.0% cobalt concentration was obtained about 4.81?. The obtained value is slightly larger than the experimental value. The calculated band gap of CoxTi1-xO2 at 0.0% cobalt concentration is 3.0 eV which consistent with other reports. The calculated band gap for 16.6% is 0.5 eV, for 33.3% is 0.1 eV and for 50.0% is approximately 0.0 eV. The calculated band gap of CoxTi1-xO2 decreased with increased cobalt concentration. On the other hand at 0.0% cobalt concentration, the magnetization is zero and at 50.0% cobalt concentration, magnetization is 3.36 Bohr mag/cell. The density of states calculation for spins up and spins down are symmetric at 16.6% and 33.3% cobalt concentration. At 50.0% cobalt concentration the density of states shows asymmetric for spin up and spin down which indicates the ferromagnetic nature.
关键词： Band structure,Magnetization,Equilibrium lattice constant,Density function theory (DFT),Density of State (DOS)
更新于2025-09-23 15:21:01