As a proof of concept, we evaluated the purity of the electroluminescence. Both 1 and 2 showed pure deep blue electroluminescence (456 nm, FWHM 16.5 nm and 464 nm, FWHM 15 nm, respectively) essentially at the same wavelength as photoluminescence (455 nm, FWHM 14.9 nm and 463 nm, FWHM 14.7 nm; Fig. ), emitting very close to the Rec.2020 target blue on the Commission internationale de l'éclairage (CIE) 1931 chromaticity diagram (Fig. ). We found the stability of electroluminescence of the MLA•QDs noteworthy (Fig. ). 1 electroluminesced at 456 nm with a turn-on voltage of »6 V and continued to emit at the same wavelength even at 11 V. Similarly, 2 remained stable under the same operating conditions. The high PLQY, low knr, color purity, and stability suggest that the MLA•QD4 has excellent size uniformity and minimum structural defects. Taken together with the simplicity of the procedure and the mildness of the synthetic conditions, the data illustrate the advantages of the room-temperature self-organization approach for preparing structurally homogeneous magic-sized nanoclusters. Finally, we addressed questions seldom asked in QD research on the number and location of Br atoms, MLA, and OAMH + on an individual QD4 particle. The high purity and structural homogeneity of the isolated QD4 nanoclusters allowed us to answer these questions using infrared (IR), energy-dispersive X-ray spectroscopy (EDX), and SMART-EM. IR analysis of a QD film on glass indicated that MLA is fully deprotonated (Figure ). EDX analysis of the same sample on a graphene sheet revealed the elemental composition of the QD (Fig. , Figure ). The first row in this figure shows a prototypical neutral QD4, Cs112Pb64Br240 (Fig. ). Of its 112 Cs cations, 27 are located in the crystal lattice and 85 on the surface. Among 240 Br atoms, 96 monovalent Br ions are located on the surface. The second row shows the experimental composition of MLA•Cs•QD4 (2). EDX analysis revealed that it has a total of 58 Cs, hence suggesting that only 31 Cs atoms are located on the surface; that is, 5 Cs atoms on each face. It has lost 3 ± 6 surface Br atoms, and gained 9.6 ± 2 MLA molecules, suggesting that one MLA replaced one Br atom on each of the eight corners. The third row shows MLA•MA•QD4 (1). It has lost 29 ± 6 surface Br atoms replaced by 9 ± 1 MLA, suggesting that one MLA acts as a tridentate ligand to replace three Br atoms on each corner 34 (cf Fig. ). Interestingly, the nanoclusters synthesized with 15 equiv of added OA also had 8 acid molecules/nanocluster, suggesting that one OA anion is located also on each corner. The OA•QD4 lacks as many as 48 Br atoms, leaving many defective Pb coordination sites.