Considerably enhanced exciton emission of CsPbCl3 perovskite quantum dots by the introduction of potassium and lanthanide ions

Abstract

The photoluminescence quantum yield (PLQY) of blue-violet emission of CsPbCl₃ quantum dots (QDs) is still low, which has limited their application in multi-colour displays. It is important to search for efficient perovskite phosphors within this wavelength range. In this work, we first considerably enhanced the photoluminescence quantum yield (PLQY) of the CsPbCl₃ QDs from 3.2 to 10.3% by the introduction of potassium ions (K⁺). Then, various lanthanide elements (La, Y, Eu, Lu) were further doped into K_xCs_1−xPbCl₃ QDs. The lanthanide doped K_xCs_1−xPbCl₃ QDs still demonstrated emissions around 408 nm and the PLQY was further improved to 31%. Finally, we carried out anion exchange by gradually substituting chlorine with bromine. Efficient and tunable emissions ranging from 408–495 nm were obtained, with a maximum PLQY of 90%. This work provides a new approach to improve the efficiency of the blue-violet light of perovskite QDs.