Efficient solid-state photoluminescence based on sodium citrate and CsPbI3 quantum dots

The development of pure red-emitting CsPbI 3 quantum dots (QDs) has been hindered by challenges including long-term instability, low yield and photoluminescence quantum yields (PLQYs), and self-absorption issues in solid-state applications. Herein, sodium citrate (SC) passivated CsPbI 3 QDs are prepared by using a simple post-treatment method, which is also applicable to other CsPbX 3 QDs. Due to the chelating coordination role of citrate, the PLQY of red SC-CsPbI 3 can reach 96 %. In addition to its passivating role, SC also acts as a matrix to increase inter-particle distances, reducing self-absorption and acquiring high PL intensity. Furthermore, SC treatment can also increase the yield of smaller QDs, which are typically challenging to isolate using conventional centrifugation methods. The passivation afforded by SC results in enhanced thermal and air stability in the samples. We utilized this narrow-band red phosphor to fabricate white light-emitting diodes (WLEDs) for lighting and display applications. Upon incorporating the red phosphor into the commercial WLED, there is a notable enhancement in the color rendering index (CRI), signifying its substantial impact on lighting WLED. For display application, the perovskite-based WLED achieves a color gamut coverage reaching up to 120 % of the National Television System Committee (NTSC) standard. This remarkable performance also underscores its significant potential for applications in display area.