Na-doping CsPbBr3 quantum dots prepared via ion exchange for bright and stable blue-to-red photoluminescence

Abstract

The low photoluminescence (PL) efficiency and bad stability have been great attention for CsPbX3 quantum dots (QDs). In this work, sodium ions (Na+) derived ion exchange for CsPbBr3 QDs was tested to study the tunable PL and stability. After doping with Na+ ions, the PL quantum yields (PLQYs) of CsPbBr3 QDs was increased from 52.6 to 94.3%. Various characteristics confirm Na+ ions occupied the position of cesium (Cs) position in CsPbBr3. The blue-shifted PL peaks from Na:CsPbBr3 QDs further proved that Na+ ions were successfully incorporated into the lattices of CsPbBr3. The stability test indicates that the introduction of Na+ ions improved the chemical environment of CsPbBr3 QDs to prevent the PL quenched. Finally, the post-treatment of PbCl2 and PbI2 solution was used to conduct anion exchange reaction of Na:CsPbBr3. The PL in whole visible light region was obtained by controlling the exchange amount of I and Cl ions. The PLQYs and stability of the QDs was further improved especially for red-emitting perovskite QDs. The high PLQYs and the PL in whole visible light region make an important application in imaging. This work provides a new approach for getting high PLQYs and adjusting PL spectra from perovskite QDs.