Fig. 4. (a) PL spectra of TCP:Ce and TCSP:Ce (0 < x ≤ 3) under 310 nm excitation. (b) IQE under 310 nm excitation. (c) Debye temperature (ΘD) estimated with DFT calculations. (d) Top: high-resolution XPS energy spectra Ce in TCSP:Ce (x = 1.5) and bottom: ratio of Ce3+ in TCP:Ce and TCSP:Ce (0 < x ≤ 3). (e) Schematic diagram of improving performance by forming Solid solution-biphasic system, increasing entropy and enhancing the rigid host-structure.