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The influence of electrode for electroluminescence devices based on all-inorganic halide perovskite CsPbBr<sub>3</sub>
摘要： Electroluminescence devices based all-inorganic halide perovskite material with the excellent luminescence performance have been studied extensively in recent years. However, the important role for the electrodes of electroluminescence devices is payed few attention by theoretical and experimental studies. Appropriate electrodes can reduce the Schottky barrier height to decrease the energy loss, and prevent the metal impurities from diffusing into the perovskite material to generate deep traps levels, which improves the luminous efficiency and lifetime of devices. In this paper, not only the interface effects between CsPbBr3 and common metal electrode (Ag, Au, Ni, Cu and Pt) are studied by first-principle calculations, but also the diffusion effects of metal electrode atom into the CsPbBr3 layer are also explored by nudged elastic band calculations. The calculated results show the metal Ag is more suitable for the cathode for CsPbBr3 electroluminescence devices, while the metal Pt is more applicable for the anode. Based on the overall consideration about the interface effects and diffusion effects of the CsPbBr3-metal electrode junctions, the essential principle provide a valuable reference how to select the suitable electrodes for other electroluminescence devices.
关键词： electroluminescence devices,diffusion effects,Schottky barrier height,CsPbBr3,all-inorganic halide perovskite,metal electrodes
更新于2025-09-23 15:19:57
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Lead-free all-inorganic cesium tin iodide perovskite for filamentary and interface-type resistive switching toward environment-friendly and temperature-tolerant nonvolatile memories
摘要： Recently, organometallic and all-inorganic halide perovskites (HPs) have become promising materials for resistive switching (RS) nonvolatile memory devices with low-power consumption, because they show current–voltage hysteresis caused by fast ion migration. However, the toxicity and environmental pollution potential of lead, a common constituent of HPs, has limited commercial applications of HP-based devices. Here, RS memory devices based on lead-free all-inorganic cesium tin iodide (CsSnI3) perovskites with temperature-tolerance are successfully fabricated. The devices exhibit reproducible and reliable bipolar RS characteristics in both Ag and Au top electrodes (TEs) with different switching mechanisms. The Ag TE devices show filamentary RS behavior with ultra-low operating voltages (< 0.15 V). In contrast, the Au TE devices have interface-type RS behavior with gradual resistance changes. This suggests that the RS characteristics are attributed to either the formation of metal filaments or the ion migration of defects in HPs under applied electric fields. These distinct mechanisms may permit the opportunity to design devices for specific purposes. This work will pave the way for lead-free all-inorganic HP-based nonvolatile memory for commercial applications of HP-based devices.
关键词： valence change mechanism,electrochemically metallization,all-inorganic halide perovskite,lead-free halide perovskite,resistive switching memory
更新于2025-09-19 17:15:36
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Zn-Alloyed All-Inorganic Halide Perovskite-Based White Light-Emitting Diodes with Superior Color Quality
摘要： Recently, lead halide perovskite nanocrystals (NCs) have gained tremendous attention in optoelectronic devices due to their excellent optical properties. However, the toxicity of lead limits their practical applications. Here, the synthesis of Zn2+-alloyed CsZnxPb1-xX3 (up to 15%) NCs is reported to achieve lead-reduced white light-emitting diodes (WLEDs). The incorporation of Zn2+ into CsPbX3 host NCs results in a lattice contraction, without altering the structure and morphology, which has a direct effect on the optical properties. The blue-shifts in the photoluminescence emission and increase in bandgap is observed while retaining high photoluminescence quantum yield. Then by engineering the different compositions of halides for 15% Zn2+-alloyed CsZnxPb1-xX3 NCs, tunable emission (411–636 nm) is obtained. Notably, the WLEDs are experimentally demonstrated employing the lead-reduced NCs (blue, green, yellow, and red). By varying the ratios of the amount of NCs, white lights with a tunable correlated-color temperature (2218–8335 K), an exemplary color-rendering index (up to 93) and high luminous efficacy of radiation (268–318 lm·W?1) are obtained. Best of our knowledge, these are superior to other reported WLEDs based on CsPbX3 NCs doped with transition metal ions. This work places the halide perovskite NCs one-step closer in designing the environmentally benign and energy-efficient WLEDs.
关键词： White Light-emitting Diodes,Zn-Alloyed,Color Quality,All-inorganic Halide perovskite
更新于2025-09-12 10:27:22
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High-Quality All-Inorganic Perovskite CsPbBr3 Quantum Dots Emitter Prepared by a Simple Purified Method and Applications of Light-Emitting Diodes
摘要： High-quality perovskite CsPbBr3 quantum dots (QDs-CsPbBr3) were prepared using the ultrasonic oscillation method, which is simple and provides variable yield according to requirements. The emission spectra over a large portion of the visible spectral region (450–650 nm) of QD-CsPbX3 (X = Cl, Br, and I) have tunable compositions that can be halide exchanged using the halide anion exchange technique and quantum size-effects. A strong peak with high intensity of (200) lattice plane of purified QDs-CsPbBr3 film is obtained, confirming the formation of an orthorhombic perovskite crystal structure of the Pnma space group. The photoluminescence of QDs-CsPbBr3 was characterized using a narrow line-width emission of 20 nm, with high quantum yields of up to 99.2%, and radioactive lifetime increasing to 26 ns. Finally, through the excellent advantages of QDs-CsPbBr3 mentioned above, purified perovskite QDs-CsPbBr3 as an active layer was utilized in perovskite quantum dot light-emitting diodes structure applications. As a result, the perovskite QDs-CsPbBr3 light-emitting diodes (LEDs) exhibits a turn-on voltage of 7 V and a maximum luminance of 5.1 cd/m2.
关键词： all-inorganic halide perovskite,perovskite CsPbBr3,quantum dot light-emitting diodes,quantum dots
更新于2025-09-11 14:15:04
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Design principle of all-inorganic halide perovskite-related nanocrystals
摘要： All-inorganic halide perovskite (AIHP)-related (e.g., CsPbBr3, Cs4PbBr6, and CsPb2Br5) nanocrystals have attracted great research interest in the recent three years, owing to their unique optical properties. However, rational structural and compositional control of these nanocrystals is still challenging, particularly using the room temperature saturated recrystallization (RTSR) method. Here, we revealed that the structure and the composition of the nanocrystals fabricated by the RTSR approach are highly dependent not only on the previously thought concentration ratio of PbBr2 and CsBr in N-dimethylformamide (DMF), but the previously neglected absolute concentration and reaction time. This is the reason why pure AIHP-related nanocrystals are usually difficult to prepare using the RTSR method. Through a series of carefully designed experiments, we obtained the evolution trend of the precipitation rate of PbBr2 and CsBr within a wide concentration range in DMF. Based on the understanding of the growth mechanism, we achieved preparation of pure or a mixture of CsPbBr3, Cs4PbBr6, and CsPb2Br5 nanocrystals through either control of the concentration of PbBr2 and CsBr or the reaction time. This study deepens our understanding of the growth mechanism of AIHP-related nanocrystals, paving the way for future engineering of nanocrystals with desired structures and compositions. These structures with desired compositions will definitely have promising applications in optical and optoelectronic devices.
关键词： nanocrystals,All-inorganic halide perovskite,room temperature saturated recrystallization,optical properties,optoelectronic devices
更新于2025-09-10 09:29:36