No abstract

Indium phosphide (InP) core/shell quantum dots (QDs) without intrinsic toxicity have shown great potential to replace the widely applied cadmium‐containing QDs in next‐generation commercial display and lighting applications. However, it remains challenging to synthesize InP core/shell QDs with high quantum yields (QYs), uniform particle size, and simultaneously thicker shell thickness to reduce nonradiative Förster resonant energy transfer (FRET). Here, thick InP‐Based QLEDs shell InP/GaP/ZnS//ZnS core/shell QDs with high stability, high QY (≈70%), and large particle size (7.2 ± 1.3 nm) are successfully synthesized through extending the growth time of shell materials along with the timely replenishment of shelling precursor. The existence of GaP interface layer minimizes the lattice mismatch and reduces interfacial defects. While thick ZnS shell, which suppresses the FRET between closely packed QDs, ensures high PL QY and stability. The robustness of such properties is demonstrated by the fabrication of green electroluminescent LEDs based on InP core/shell QDs with the peak external quantum efficiency and current efficiency of 6.3% and 13.7 cd A−1, respectively, which are the most‐efficient InP‐based green quantum dot light‐emitting diodes (QLEDs) till now. This work provides an effective strategy to further improve heavy‐metal‐free QLED performance and moves a significant step toward the commercial application of InP‐based electroluminescent device.

Low-cost and efficient electrocatalysts are urgently required for the N 2 reduction reaction (NRR) to produce NH 3 under ambient conditions. By using first-principles calculation, we systematically investigated the NRR catalytic activity of the transition metal (TM, including Mn, Fe, Co, and Ni) monomer-, dimer-, and trimer-anchored graphdiyne (GDY) monolayers. It is shown that most of the TM monomer-and dimer-anchored GDY monolayers have enhanced NRR catalytic activity compared with the Ru(0001) stepped surface. Especially, the Co dimer-anchored GDY monolayer (Co 2 @GDY) exhibits the best NRR catalytic activity with the onset potential of −0.43 V and a high ability to suppress the competing hydrogen evolution reaction. The high NRR catalytic activity of Co 2 @GDY could be attributed to the localized electronic states near the Fermi level and the strong electron-donating ability of the GDY monolayer. Furthermore, an approximate linear trend between the predicted onset potential and the N adsorption energy is revealed, which may act as a simple descriptor for the intrinsic NRR catalytic activity of such catalysts. Our findings not only propose an efficient and low-cost double-atom catalyst for NRR but also provide a new clue for designing TM atomic catalysts based on GDY sheets for various electrocatalysis applications.

Nanoparticle/MOF materials usually have new or enhanced applications compared with bare MOF or NPs.