Bandgap Engineering of Sr2+/Cl– Co-Doped CsPbBr3 Quantum Dot-Based Glass with Narrow Stokes Shift for Blue-Violet-Excited Color-Conversion Displays

CsPbX 3 (X = I, Br, Cl) perovskite quantum dots (PQDs) are promising for optoelectronic applications owing to their tunable bandgap, high photoluminescence (PL) quantum yield, and narrow emission bandwidth. However, CsPbBr 3 PQDs exhibit a large Stokes shift (>155 nm) and are mainly excited by near-ultraviolet light (∼365 nm), resulting in substantial energy loss and limiting their compatibility with blue light-emitting diodes (LEDs) excitation. Herein, Sr 2+ /Cl – codoped CsPbBr 3 PQDs embedded in zinc borosilicate (ZBS) glass powders were developed to regulate the band structure. Sr 2+ incorporation significantly enhances PL performance. Notably, CsPb 0.5 Sr 0.5 Br 3 PQDs exhibit ∼1.6 times higher PL intensity than undoped samples with a slight red-shift (∼5 nm). Meanwhile, the bandgap of CsPb 0.1 Sr 0.9 Br 3 PQDs is widened to 3.12 eV compared to 2.36 eV for CsPbBr 3 . Totally different with undoped PQDs, the excitation peak of CsPb 0.1 Sr 0.9 Br 3 PQDs covers the desired blue-violet region in the range of 400–480 nm and the maximum peak is located at 414 nm, which displays a narrow Stokes shift of 106 nm. Further, Cl – ions substitution in Sr-doped host materials enables the blueshift of the PL emission from 521 nm (green light) to 448 nm (blue light) via bandgap engineering accompanied by ultranarrow Stokes shift of ∼34 nm for CsPb 0.1 Sr 0.9 BrCl 2 sample. The Sr-doped PQDs embedded in ZBS glass also demonstrate excellent water resistance, retaining ∼96% of their initial PL intensity after immersion in deionized water for more than 60 days. Thus, the ultrastable PQDs glass powders can be effectively excited by the blue-violet light chip (410 nm-460 nm) via bandgap engineering possess and demonstrate promising application potential in color-conversion display devices, wide-color-gamut backlight systems and screen-printable emissive display films.