Excellent exciton luminescence of CsPbI3 red quantum dots in borate glass

Abstract

We have fabricated CsPbI3 perovskite quantum dots in a borate glass by melt-quenching technique. Three representative samples with different treatment conditions are investigated. As treatment condition enhances, energy gap is extracted as 1.75–1.76 eV, and photoluminescence peak is adjustable from 675 to 691 nm. Full width at half-maximum (FWHM) varies from 43 to 37 nm. PL intensity first increases and then decreases with increasing excitation wavelength, but the peak wavelength and line-shape are independent. High PLQY values of 23.8%–61.4% are obtained. The high PLQY values are attributed to good crystal quality and less energy dissipation. PL lifetime is fitted as 24.0–28.2 ns and 100.2–123.0 ns for short and long lifetime components in bi-exponential function. For temperature from 25 to 125 °C, PL intensity decreases, but it is reversible. Exciton binding energy is extracted in the level of 375–454 meV. The FWHM broadening from 39 to 49 nm and peak blue-shift from 690 to 685 nm are investigated.