Passivation of Surface Defects by X-type Short-Chain Ligands for High Quantum Yield and Stable CsPbX₃ Quantum Dots Synthesis and Application in WLEDs

Abstract

All-inorganic CsPbX3 perovskite quantum dots have excellent optoelectronic properties and are excellent candidates for optoelectronic applications. However, the surface ligands (oleyl ammonium, oleic acid) commonly used in traditional inorganic perovskite quantum dots easily fall off from the quantum dots and their protective power is relatively weak, resulting in poor quantum yield and stability of the quantum dots, limiting their application. In this paper, we introduce an X-type short-chain ligand (DDEAB) passivation strategy to enhance the optoelectronic properties of CsPbX3 quantum dots through a facile room-temperature synthesis method and the strong affinity of X-type ligands for surface atoms. The results of TRPL and X-ray photoelectron spectroscopy showed longer lifetime and stronger surface affinity. This result confirms that didecyldimethylammonium bromide (DDEAB) has better binding to CsPbBr3 QDs and can effectively reduce surface defects and improve quantum yield. As a result, the introduction of short-chain ligands can more effectively passivate the surface halogen defects of CsPbX3 QDs, achieving high quantum yield (>90%) and long-term storage environmental stability. In addition, DDEAB-passivated CsPbBr3 QDs have been successfully applied in white light emitting diodes (WLEDs) with wider color gamut (123%), and good EL stability compared to NTSC TV color standard. Our proposed short-chain ligand DDEAB passivation strategy may provide a reference guideline for the preparation of quantum dots and photovoltaic devices with high photoluminescence and environmental stability.

Aluminum Carboxylate Modification Enabled Efficient and Stable Perovskite-Polystyrene Thin Films for Light-Emitting Applications

“…The investigation involved subjecting both samples to continuous irradiation under a high-power UV LED (5W, 365 nm). Figure d illustrates that the PL intensity of the PNCs-PS film experienced a rapid decline within 30 h. In contrast, the PNCs-Al­(PA) 2 -PS film exhibited a decrease to 78% of its initial value within the first 10 h, after which the light intensity showed a gradual drop of only 10% until 500 h. We compared our method with recently reported surface modification methods in terms of the optical properties and stability of PNCs as outlined in Table S2, which underscores the remarkable optical quality and stability of the PNCs-Al­(PA) 2 -PS film. − The polymer cladding has the dual function of acting as a waterproof barrier and enhancing the machinability of the composite films, making them suitable for use in LED backlights and other optoelectronic applications.…”

Application of a Perovskite NIR-LED with Highly Stable FAPbI3@SiO2 Core–Shell Nanocomposites in a SPR Sensing Platform

“…The effective passivation of surface defects on FAPbI 3 NIPQDs by TOPO ligands reduced trap-state radiation and enhanced the PLQY. 31 Once the concentration of TOPO reached 0.07 mmol, even the τ avg continued to increase, and the weight factors indicated that the increase was due to an increase in A 2 . This can be attributed to the quantum confinement effect brought about by an excess of TOPO ligands, which resulted in the formation of additional surface vacancies and quenching.…”

“…These results indicate that with increasing TOPO concentration, the weight percentage of radiative transitions from the band edge increased. The effective passivation of surface defects on FAPbI 3 NIPQDs by TOPO ligands reduced trap-state radiation and enhanced the PLQY . Once the concentration of TOPO reached 0.07 mmol, even the τ avg continued to increase, and the weight factors indicated that the increase was due to an increase in A 2 .…”

“…The difference in peak area between the two samples indicates that an inclusion of TOPO ligand reduces the size of FAPbI 3 NIPQDs, resulting in a larger specific surface area and a greater number of ligands bound to the surface of FAPbI 3 NIPQDs. In addition, the chemical interaction between TOPO and FAPbI 3 NIPQDs was analyzed using 31 P NMR, as shown in Figure S4. No significant chemical shift was observed in the characteristic peak of TOPO at 42.5 ppm when the FA precursor and TOPO were dissolved in d-8 toluene (blue line), indicating the absence of a significant chemical interaction between TOPO and the FA precursor.…”

“…X-ray photoelectron (XPS) spectroscopy was conducted using a PHI 5000 instrument (Versa Probe). 31 P nuclear magnetic resonance (NMR) spectroscopy was performed using a 600 MHz NMR spectrometer (BRUKER AVANCE III).…”