Locking Broadband Bi3+ Luminescence Color From 6 to 423 K

Wide-temperature color-stable luminescence is a critical requirement for high-performance phosphor-converted light-emitting diodes (pc-LEDs). However, broadband emitters, particularly Bi 3+ -activated phosphors, universally suffer from thermally induced spectral drift. This behavior originates from their intrinsic sensitivity to temperature-dependent crystal-field reconfiguration and electron–phonon coupling (EPC) under thermal cycling conditions. To overcome the above bottleneck, we propose a lattice engineering strategy grounded in an intrinsically low-thermal-expansion host, using Gd 2 Zr 2 O 7 (GZO) as a model system. Benefiting from its ultralow coefficient of thermal expansion (6.56 × 10 −6 K −1 ), the GZO host robustly suppresses lattice distortion and markedly attenuates EPC effects over an ultra-wide temperature range (6–423 K). Such unique structural characteristics decouple Bi 3+ emission from thermally driven lattice dynamics, endowing the phosphor with intrinsic thermal spectral stability. The optimized composition, Gd 2 Zr 2 O 7 : 0.03Bi 3+ , demonstrates outstanding chromatic stability across the entire temperature range, with negligible average CIE coordinate deviations of Δ Δ $\Delta $ x = 0.00987 and Δ Δ $\Delta $ y = 0.01205. Furthermore, it exhibits unique excitation- and temperature-responsive luminescence, enabling flexible dual-mode spectral modulation. This study transforms the design route of wide-temperature color-stable phosphors from passive external heat dissipation to active intrinsic low-expansion host engineering and provides a general strategy for exploiting anti-color-drift broadband luminescent materials.