• • Sb3+-doped (ETPP)2ZnBr4 achieves 55.4% quantum efficiency at 763 nm under 450 nm excitation, directly matching commercial blue LED chips (440–480 nm), which eliminates the need for UV pumps and reduces system cost for NIR spectroscopy applications.
• • Ambient synthesis yields 14.5 g of Sb3+-doped (ETPP)2ZnBr4 in a single batch with 80% yield, demonstrating scalability for industrial production; this contrasts with typical laboratory-scale syntheses that yield <1 g, addressing a critical bottleneck in phosphor manufacturing.
• • Sb3+-doped (ETPP)2ZnCl4 exhibits 95.3% quantum efficiency at 702 nm but requires UV excitation (376 nm), highlighting a trade-off between efficiency and excitation wavelength; Br/Cl substitution enables tunable emission from 702 to 763 nm, allowing spectral tailoring for specific applications.
• • The phosphor exhibits excellent air, photo, and thermal stability, with no reported degradation under ambient conditions; this is essential for practical NIR LED devices, as many lead-free halides suffer from moisture-induced degradation, limiting operational lifetime.