Tuning luminescence wavelength of CsPbI3 quantum dots glasses using Sn doping and rapid thermal treatment for wide gamut display

CsPbI3 quantum dots (QDs) glasses (QDGs) may have excellent photoluminescence (PL) characteristics and stability, which is suitable for wide gamut backlight display. The key problem is to tune the long PL peak to a suitable range of 635-645 nm, and to keep good PL quantum yield (PLQY). We have fabricated CsPbI3 and Sndoped CsPbI3 QDGs in borogermanate glass matrix by melt quenching and thermal treatment. The nanocrystal QDs are confirmed as PL active cubic CsPbI3 by TEM. To tune the PL peak, small amount of Sn was doped, and two kinds of thermal treatment were used, that were conventional thermal treatment (CTT) and rapid thermal treatment (RTT). For both CTT and RTT, the PL intensity slightly decreases with increasing Sn doping concentration. The peak wavelength can meet the requirement only by RTT. The treatment conditions 540 degrees C 10 min and Sn doping concentration of 0.3-0.7 % are suitable. Excitation wavelength with strong PL intensity is located at 450 nm, which matches commercial blue LED. PL decay shows average lifetime has strong correlation with the peak wavelength. For the RTT samples of 540 degrees C/10 min, PL decay lifetime decreases with increasing Sn. The transition wavelengths of transmittance and absorption spectra correlate to the PL peak wavelength. PL peak tuning mechanism is considered as bandgap adjusting effect by B-site CsPb1-xSnxI3 QDs and quantum confinement. By using the Sn-doped CsPbI3 QDGs with suitable PL peak, color gamut can be improved by 4%-8%. The temperature characteristics of PL spectra have been fitted for CTT and RTT samples with large exciton binding energy of 349-408 meV. Temperature cycle characteristics are excellent. The fabricated Sn-doped CsPbI3 QDGs are suitable for wide gamut display applications.