Localized Surface Plasmon Enhanced All‐Inorganic Perovskite Quantum Dot Light‐Emitting Diodes Based on Coaxial Core/Shell Heterojunction Architecture

Abstract

This work presents a strategy of combining the concepts of localized surface plasmons (LSPs) and core/shell nanostructure configuration in a single perovskite light-emitting diode (PeLED) to addresses simultaneously the emission efficiency and stability issues facing current PeLEDs' challenges. Wide bandgap n-ZnO nanowires and p-NiO are employed as the carrier injectors, and also the bottom/upper protection layers to construct coaxial core/shell heterostructured CsPbBr 3 quantum dots LEDs. Through embedding plasmonic Au nanoparticles into the device and thickness optimization of the MgZnO spacer layer, an emission enhancement ratio of 1.55 is achieved. The best-performing plasmonic PeLED reaches up a luminance of 10 206 cd m −2 , an external quantum efficiency of ≈4.626%, and a current efficiency of 8.736 cd A −1 . The underlying mechanisms for electroluminescence enhancement are associated with the increased spontaneous emission rate and improved internal quantum efficiency induced by exciton-LSP coupling. More importantly, the proposed PeLEDs, even without encapsulation, present a substantially improved operation stability against water and oxygen degradation (30-day storage in air ambient, 85% humidity) compared with any previous reports. It is believed that the experimental results obtained will provide an effective strategy to enhance the performance of PeLEDs, which may push forward the application of such kind of LEDs.

Hole-Injection Layer-Free Perovskite Light-Emitting Diodes

“…As shown in Figure 2a, two characteristic diffractions can be observed at 14.89°and 30.35°, which are indexed to the (100) and (200) diffractions of cubic CsPbBr 3 (space group Pm3̅ m, a = 2.95 Å). 24 By using the Debye− Scherrer equation, the grain size was calculated to be ∼352 nm, well consistent with the observations in the top-view SEM image of CsPbBr 3 thin films. The measured X-ray photoelectron spectroscopy (XPS) results of the produced CsPbBr 3 are displayed in Figure 2b, in which Cs, Br, Pb, N, and C elements were detected with a stoichiometric ratio of 1.00:0.93:2.79 for Cs, Pb, and Br elements.…”

“…Here, sample A was taken as an example because three samples share almost the same spectra characteristics. As shown in Figure a, two characteristic diffractions can be observed at 14.89° and 30.35°, which are indexed to the (100) and (200) diffractions of cubic CsPbBr 3 (space group Pm 3̅ m , a = 2.95 Å) . By using the Debye–Scherrer equation, the grain size was calculated to be ∼352 nm, well consistent with the observations in the top-view SEM image of CsPbBr 3 thin films.…”

Textured Inorganic Perovskite Interlayer Enhances Carrier Extraction for Organic Solar Cells

“…The characteristic diffraction peaks at 15.2°, 21.5°, 30.4°, 35.2°, and 37.7°correspond to the (100), ( 110), (200), (210), and (211) planes, respectively, confirming the formation of a cubic phase. 30 Ultraviolet−visible (UV−vis) absorption spectroscopy and steady-state photoluminescence (PL) spectra reveal an excitonic absorption peak and a narrow emission peak at 515 nm (Figure S1b), consistent with a wide optical bandgap (E g ) of 2.34 eV derived from Tauc plot analysis (Figure S1c). Time-resolved photoluminescence (TRPL) decay dynamics yield an average carrier lifetime (τ avg ) of 14.31 ns (Figure S1d).…”

Boosting the Efficiency of High-Resolution Quantum Dot Light-Emitting Devices Based on Localized Surface Plasmon Resonance

“…It has also been reported that the coupling process between LSPR and excitons is much faster than the spontaneous recombination, thus the exciton lifetime in LSPR-enhanced devices is reduced. 27,28 Accordingly, as shown in Figure 3d, the PL intensity of QDs with the Au LSPR structure is visibly raised. Figure 3e presents the ratio of PL enhancement by LSPR versus the emission wavelength.…”