Perovskite light-emitting diodes (PeLEDs) have drawn great research attention because of their outstanding electroluminescence performance by solution processing. PeLEDs made by thermal evaporation are relatively rarely explored but are compatible to existing organic light-emitting diode industrial lines. Blue-emitting PeLEDs are all based on organic-containing perovskites, rather than more stable all-inorganic perovskites because of their poor solubility, too fast crystallization, uneven discrete films, and unattainable pure blue emission. Here, we report all-inorganic, vacuum-processed blue PeLEDs. High-throughput combinatorial approaches are employed to optimize Cs-Pb-Br-Cl composition in our dual-source co-evaporation system to achieve the balance between film photoluminescence and injection efficiency. The as-deposited perovskite films demonstrated excellent intrinsic stability against heat, UV-light, and humidity attack. A series of PeLEDs were obtained covering the standard blue spectral region with a best luminance of 121 cd/m and an external quantum efficiency of 0.38%. We believe that the vacuum processing strategy demonstrated here provides a very promising alternative way to produce efficient and stable all-inorganic blue-emitting PeLEDs.
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http://dx.doi.org/10.1021/acsami.9b17164 | DOI Listing |
Nanoscale
January 2025
Department of Photonics and Institute of Electro-Optical Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Electroluminescent (EL) devices consisting of a single metal-semiconductor contact and a gate effect structure have garnered significant attention in the field of perovskite light-emitting devices. This interest is largely due to the thermal stability of the active layer and the simplicity of the device structure. However, the application of these devices in large-area light-emitting applications is hindered by the inherently low carrier mobility in perovskite materials.
View Article and Find Full Text PDFSmall
January 2025
Department of Chemistry, National Taiwan University, Taipei, 10617, Taiwan.
Addressing the challenges of the efficiency and stability of red perovskite nanocrystals is imperative for the successful deployment of these materials in displays and lighting applications. the structural dynamic changes of red perovskite quantum dots (PQDs) are explored using a flow chemistry system to solve the above hurdles. First, the ultrabright red-emitting PQDs of CsPb(Br,I) are achieved by adjusting ligand distribution (oleic acid and oleyamine) in combination with different flow rates and equivalence ratios.
View Article and Find Full Text PDFNano Lett
January 2025
Key Laboratory of Materials Physics of Ministry of Education, School of Physics, Zhengzhou University, Daxue Road 75, Zhengzhou 450052, China.
Ternary copper halides with an eco-friendly property have emerged as attractive candidates to replace toxic lead-containing perovskites for light-emitting diodes (LEDs), yet achieving long-wavelength electroluminescence remains unexplored. Herein, we report the first realization of orange-emitting LEDs (595 nm) based on nontoxic organic-inorganic PEACuI (PEA = β-phenylethylamine) films enabled by a nonionic surfactant poly(propylene glycol) bis(2-aminopropyl ether) (APPG) chemisorption. Experimental and theoretical analyses rationalize that the APPG additive has strong chemisorption with the Cu-I framework within the grain boundaries of PEACuI films, which not only improves the film's morphology but also passivates the iodine vacancy defects.
View Article and Find Full Text PDFAdv Mater
January 2025
Department of Physics, SUNY University at Buffalo, Buffalo, NY, 14220, USA.
Quasi-2D perovskite made with organic spacers co-crystallized with inorganic cesium lead bromide inorganics is demonstrated for near unity photoluminescence quantum yield at room temperature. However, light emitting diodes made with quasi-2D perovskites rapidly degrade which remains a major bottleneck in this field. In this work, It is shown that the bright emission originates from finely tuned multi-component 2D nano-crystalline phases that are thermodynamically unstable.
View Article and Find Full Text PDFSmall
January 2025
Department of Materials Science and Engineering, and Center for Functional Photonics (CFP), City University of Hong Kong, Hong Kong SAR, 999077, P. R. China.
Metal halide perovskite nanoplatelets (NPls) possess ultra-narrow photoluminescence (PL) bands tunable over the entire visible spectral range, which makes them promising for utilization in light-emitting diodes (LEDs) with spectrally pure emission colors. This calls for development of synthetic methods toward perovskite NPls with a high degree of control over both their thickness and lateral dimensions. A general strategy is developed to obtain such monodisperse CsPbI NPls through the control over the halide-to-lead ratio during heating-up reaction.
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