Efficient and large-area all vacuum-deposited perovskite light-emitting diodes via spatial confinement

Abstract

With rapid advances of perovskite light-emitting diodes (PeLEDs), the large-scale fabrication of patterned PeLEDs towards display panels is of increasing importance. However, most state-of-the-art PeLEDs are fabricated by solution-processed techniques, which are difficult to simultaneously achieve high-resolution pixels and large-scale production. To this end, we construct efficient CsPbBr3 PeLEDs employing a vacuum deposition technique, which has been demonstrated as the most successful route for commercial organic LED displays. By carefully controlling the strength of the spatial confinement in CsPbBr3 film, its radiative recombination is greatly enhanced while the nonradiative recombination is suppressed. As a result, the external quantum efficiency (EQE) of thermally evaporated PeLED reaches 8.0%, a record for vacuum processed PeLEDs. Benefitting from the excellent uniformity and scalability of the thermal evaporation, we demonstrate PeLED with a functional area up to 40.2 cm2 and a peak EQE of 7.1%, representing one of the most efficient large-area PeLEDs. We further achieve high-resolution patterned perovskite film with 100 μm pixels using fine metal masks, laying the foundation for potential display applications. We believe the strategy of confinement strength regulation in thermally evaporated perovskites provides an effective way to process high-efficiency and large-area PeLEDs towards commercial display panels.

Polymer additive engineering of K2CuBr3 nanocrystalline films to achieve efficient and stable deep-blue emission

“…The fitting results show a value of E b = 139.4 ± 7.9 meV for the treated K 2 CuBr 3 films, higher than that of the control sample (113.6 ± 0.5 meV), as shown in figures 4(b)-(e). The higher E b of PMMA-treated K 2 CuBr 3 films may result from an enhanced quantum confinement induced by grain size reduction, as observed in lead-based perovskite nanostructures [36]. Such a higher E b in PMMA-treated films favors an efficient radiative recombination and leads to a brighter blue emission, which is consistent with the changing trends of PLQY and PL decay discussed above.…”

Enhanced Ultraviolet Spontaneous and Lasing Emission Through Interface Engineering of Patterned Vertically Aligned ZnO Nanowires

“…[36][37][38] Through surface/interface engineering, it is believed that ZnO NW emission devices could be optimized through light-matter interaction modulation for tailoring the optical process. [33,[39][40][41] Here, light confinement modulation was realized based on ZnO NWs through interface engineering end facets through introducing Pt metal, optimized UV spontaneous and lasing emission was realized, supporting an effective optical path through interface engineering for photon extraction, thus a larger internal gain was realized for enhanced spontaneous and lasing emissions. As proven by experimental results, through interface integration with Pt metal for ZnO NWs, 170% photoluminescence (PL) emission enhancement accompanied by 145% broaden emission spectra width (FWHM) in the UV region was obtained.…”

“…[ 36–38 ] Through surface/interface engineering, it is believed that ZnO NW emission devices could be optimized through light‐matter interaction modulation for tailoring the optical process. [ 33,39–41 ]…”

Large‐Area and Efficient Sky‐Blue Perovskite Light‐Emitting Diodes via Blade‐Coating

“…[14,16,[19][20][21] Recently, large-area PeLEDs have attracted growing attentions due to their potential applications in solid-state lighting, and a number of breakthroughs have been made. [24][25][26][27] For example, spin coating was tried to make large-area nearinfrared and green PeLEDs with device areas of 9 cm 2 . [24,25] A thermal evaporation method was also utilized to fabricate largearea green PeLEDs up to 40.2 cm 2 with a peak EQE of 7.1%.…”

“…[24,25] A thermal evaporation method was also utilized to fabricate largearea green PeLEDs up to 40.2 cm 2 with a peak EQE of 7.1%. [26] We recently developed a robust blade-coating technique to fabricate large-area and efficient infrared/ red PeLEDs. [27] Diluted and organoammonium-excessed precursors were adopted to increase the film formation speed, which resulted in ultra-flat films with roughness around 1 nm.…”