Locking Broadband Bi 3+ Luminescence Color From 6 to 423 K

ABSTRACT 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 x = 0.00987 and 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.