Fei Chen

Abstract The performance of red InP and blue ZnTeSe-based quantum dots (QDs) and corresponding QD light emitting diodes (QLEDs) has already been improved significantly, whose external quantum efficiencies (EQEs) and luminances have exceeded 20% and 80 000 cd m −2 , respectively. However, the inferior performance of the green InP-based device hinders the commercialization of full-color Cd-free QLED technology. The ease of oxidation of the highly reactive InP cores leads to high non-radiative recombination and poor photoluminescence quantum yield (PL QY) of the InP-based core/shell QDs, limiting the performance of the relevant QLEDs. Here, we proposed a fluoride-free synthesis strategy to in-situ passivate the InP cores, in which zinc myristate reacted with phosphine dangling bonds to form Zn–P protective layer and protect InP cores from the water and oxygen in the environment. The resultant InP/ZnSe/ZnS core/shell QDs demonstrated a high PL QY of 91%. The corresponding green-emitting electroluminescence devices exhibited a maximum EQE of 12.74%, along with a luminance of over 175 000 cd m −2 and a long T 50 @100 cd m −2 lifetime of over 20 000 h.

Abstract The external quantum efficiencies (EQE) and luminances of red InP‐based and blue ZnTeSe‐based quantum dot light‐emitting diodes (QLEDs) have exceeded 20% and 80 000 cd m −2 , respectively, and the T 50 @100 cd m −2 (time for the luminance decreasing by 50%) operational lifetime of red InP‐based QLEDs also have exceeded 1 000 000 h, nearing industrial application standards. However, the low EQE, luminance, and inferior lifetime of green InP‐based QLEDs restrict the application for their full‐color Cd‐free display and lighting applications. The large electron injection barrier and severe exciton quenching caused by defect states of ZnMgO (ZMO) nanoparticles (NPs) lead to lower electron concentration in the emitting layer, which results in reduced radiative recombination. Here, with the surface passivation of MgCl 2 , the exciton quenching sites are significantly suppressed, and the electron injection barrier is reduced owing to the conduction band minimum (CBM) levels upshift of ZMO. As a result, a high EQE of 21.43%, maximum luminance of 25 5985 cd m −2 , along with a long T 50 @1000 cd m −2 (over 4 600 h) and T 50 @100 cd m −2 (over 290 000 h) operational lifetime is achieved for green InP‐based QLEDs. These values have all exceeded the previous best values of green InP‐based QLEDs.

Abstract InP quantum dots (QDs), without heavy metals, show great potential for display and lightening applications. However, achieving efficient InP‐based quantum dot light‐emitting diodes (QLEDs) with extended operational lifetime remains challenging due to unbalanced carrier injection within the device. In this study, polyvinyl pyrrolidone (PVP) is introduced as an intermediate layer between the QDs emitting layer (EML) and the ZnMgO electron transport layer (ETL). This intermediate layer is designed to block excess electron injection into the QDs layer and simultaneously reduce leakage current. Additionally, the introduction of PVP can passivate QDs/ETL interface defects and inhibit exciton quenching of QDs by the ZnMgO ETL. The optimized device achieves a peak external quantum efficiency (EQE) of 23.5% and a long T 95 operational lifetime of over 800 h at an initial luminance of 1000 cd m −2 for red InP‐based QLEDs emitting at 624 nm. Both the EQE and the T 95 operational lifetime represent the highest values achieved for red InP‐based QLEDs to date.

Abstract Indium phosphide (InP)‐based quantum dots (QDs) have emerged as highly‐promising, environmentally friendly emitting materials for displays. However, the commonly used phosphorus precursor, tris(trimethylsilyl)phosphine ((TMS) 3 P), is expensive, flammable, and explosive, hindering its commercialization. Although tris(dimethylamino)phosphine ((DMA) 3 P) offers a more economical alternative, the resulting QDs and quantum dot light‐emitting diodes (QLEDs) have low performance because of core surface traps and ligand instability. In this study, a dual‐surface treatment strategy is developed that combines NH 4 PF 6 pre‐treatment of InP cores and OT‐based shell growth. First, NH 4 PF 6 is employed to passivate the In/P dangling bonds and remove the oxidation defects, thereby improving size uniformity. Then, 1‐octanethiol (OT) served as both sulfur source and short‐chain ligand to enhance QD stability. The optimized QDs exhibit a near‐unity photoluminescence quantum yield (PL QY) of 96% and exceptional stability, retaining 98% of their initial PL QY after 1 month in ambient air. Moreover, the OT ligand facilitates an elevated energy‐level alignment, reducing the hole injection barrier and boosting radiative recombination. As a result, the OT‐based red QLEDs achieve a record external quantum efficiency (EQE) of 21.55%, maximum luminance of 95,327 cd m −2 , and long T 50 lifetime (time for the luminance to drop to half of the initial value) of 50,066 h, setting a new state‐of‐the‐art performance for (DMA) 3 P‐based QLEDs.