Cation substitution induced highly symmetric crystal structure in cyan-green-emitting Ca2La1-Lu Hf2Al3O12:Ce3+ solid-solution phosphors with enhanced photoluminescence emission and thermal stability: Toward full-visible-spectrum white LEDs

Regulating Luminescence Thermal Quenching of Praseodymium-Doped Niobo-Tantalate Phosphor through Intervalence Charge Transfer Band Displacement

“…The more stable the 1 D 2 emission indicates that the larger the Δ E 2 value, the larger the IVCT energy level. Figures c–e and S4 show the Arrhenius formula – for calculating the thermal quenching activation energy Δ E 2 for LiNb 1– x Ta x O 3 :0.005Pr 3+ ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0). where the constants I 0 and I ( T ) are the parameters for initial temperature and any temperature ( T ) emission intensity, E represents the activation energy Δ E 2 , and A and K B (Boltzmann’s constant 8.629 × 10 –5 eV·K –1 ) are constants. With the increase of x ( x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0), the calculated values of Δ E 2 are 0.38052, 0.41274, 0.43540, 0.46734, 0.53585, and 0.62716 eV, respectively.…”

Overcoming the cyan gap for full‐spectrum lighting using cation‐substitution‐induced rigid Ca2YZr2Al3O12:Ce3+

“…As the energy difference between the lowest and highest 5d energy levels, crystal field splitting (ε cfs ) plays a significant role in spectral modulation and can be expressed as follows 57 : $$$$\begin{equation}{\varepsilon _{{\mathrm{cfs}}}} = \beta _{{\mathrm{poly}}}^Q\ R_{{\mathrm{av}}}^{ - 2}\end{equation}$$$$ $$$$\begin{equation}{R_{{\mathrm{av}}}} = \frac{1}{N}\ \mathop \sum \limits_{i\ = \ 1}^N \left( {{R_i} - 0.6\Delta R} \right)\end{equation}$$$$where $$\beta _{{\mathrm{poly}}}^Q$$ is a constant, depending on the type of coordination polyhedron. Therefore, the crystal field splitting (ε cfs ) is negatively correlated with R av .…”

“…(ii) Thermally activated 5d → 4f crossover based on the electron–phonon coupling mechanism, in which the excited state electrons can be vibrationally relaxed and returned to the 4f ground state with no light emission. (iii) Thermally activated non‐radiative relaxation enhancement with widespread non‐radiative transition between Ce 3+ in the phosphor, and thermal excitation of phonon modes increases the probability of the energy migration process making it easier for photons to enter the killer center 57,62,65,66 …”

An efficient blue–violet phosphor: an advanced material designed for high-quality full-spectrum lighting

“…The lighting and display industry heavily relies on phosphor-converted white light emitting diodes (pc-WLEDs) due to their outstanding efficiency, energy conservation capabilities, environmental friendliness, rapid response times, and long lifetime. 1–9 Presently, the key components in commercially available WLEDs are green phosphors like (Lu,Y) 3 Al 5 O 12 :Ce 3+ /Y 3 (Ga,Al) 5 O 12 :Ce 3+ , red phosphors such as (Ca,Sr)AlSiN 3 :Eu 2+ , and blue InGaN chips. Although the WLEDs obtained through this method have some advantages of simplicity and low cost, they cannot meet the requirements of healthy lighting.…”