Tailoring the refractive index and surface defects of CsPbBr3 quantum dots via alkyl cation-engineering for efficient perovskite light-emitting diodes

Water-Assisted Perovskite Quantum Dots with High Optical Properties

“…On the other hand, in the prepared MAPbBr 3 PeQDs with assisted water over 5 µL, the excess water worked to collapse MAPbBr 3 PeQDs because of their polarity, and it caused the increasing of MAPbBr 3 PeQD surface defects, resulting in a shorter τ ave . From the XPS analysis, the ratio of Br/Pb showed the near unity ideal values of 2.90 on the MAPbBr 3 PeQDs with water compared with the value of 2.75 for that without water [31]. In addition, the Br 3d 5/2 and Br 3d 3/2 peaks on the Br 3d spectra shifted to higher binding energies by 0.1 eV, which means that Pb-Br interactions on the MAPbBr 3 PeQDs were stronger after assisting water (Figures 6b and S6b) [31].…”

“…From the XPS analysis, the ratio of Br/Pb showed the near unity ideal values of 2.90 on the MAPbBr 3 PeQDs with water compared with the value of 2.75 for that without water [31]. In addition, the Br 3d 5/2 and Br 3d 3/2 peaks on the Br 3d spectra shifted to higher binding energies by 0.1 eV, which means that Pb-Br interactions on the MAPbBr 3 PeQDs were stronger after assisting water (Figures 6b and S6b) [31]. It was confirmed that the surface defects of MAPbBr 3 PeQDs were passivated due to the longer τ ave in the PL lifetime and the improvement ratio of Br/Pb by XPS measurement, which resulted in a significant improvement in PLQY.…”

Surface ligand engineering involving fluorophenethyl ammonium for stable and strong emission CsPbBr3 quantum dots and high-performance QLEDs

“…In terms of these issues, different strategies have been developed in recent years, 30–33 among which introducing new surface ligands in the synthesis of PQDs has been considered an effective strategy. Most of these new surface ligands have shorter chains than OAm and OA and are more stable in combination with PQDs.…”

“…Furthermore, compared to the linear alkyl chain ligand, phenylalkyl ammonium bromides possessing an aromatic ring were expected to promote charge transfer and thus be favorable for the improvement of the performance of QDs. 33,37 In particular, enhanced optoelectronic properties and stability of PQDs are achieved using phenylalkyl ammonium bromides such as phenylmethyl ammonium bromide (PMABr) and phenylethyl ammonium bromide (PEABr) owing to their excellent surface passivation ability. Thus, the optoelectronic performance of PQDs was significantly enhanced via a ligand exchange strategy.…”

Achieving Matrix Quantum Dot Light-Emitting Display Based on All-Inorganic CsPbBr₃ Perovskite Nanocrystal Composites

“…In particular, perovskite NCs can provide high color purity and high luminescence efficiency, which were considered to be very promising characteristics in displays [5]− [7]. In addition, the low cost and easy solution processability of perovskite materials should be expected to become cost-effective light-emitting diode (LED) applications [8]− [11]. Although the perovskite NCs was an excellent luminophore, the cesium ions and halogen ions in the perovskite NCs were all water-soluble ions, and the crystal structure was easily damaged.…”