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Insights into mechanism of size-controlled synthesis of CH3NH3PbBr3 perovskite quantum dots and large nanoparticles with tunable optical properties
摘要： There is a common phenomenon in the preparation of perovskite quantum dots (QDs) by reprecipitation method that large particles were always produced with desired QDs. Understanding the fabrication mechanism can contribute to improve this phenomenon. Herein, we demonstrate a two-step strategy for synthesis of perovskite QDs and large nanoparticles (LNPs), where the growth of QDs and LNPs involves two possible pathways, the quick intercalation reaction process and the dissolution-recrystallization process. Following two pathways, we have created QDs with high photoluminescence quantum yields (ca. 46–71%), tunable size (ca. 3.2–5.4 nm) and LNPs with tunable size from 25 to 300 nm, where their emission wavelength can be tuned from 500 nm to 534 nm. Importantly, based on the comprehensive insight into the formation mechanism, we have achieved the conversion from LNPs to QDs partly through adding surfactants properly, which is expected to pave the way for the development of pure production of perovskite QDs.
关键词： Surfactant ligands,Quantum dots,Optical properties,Hybrid organic-inorganic perovskite,Size-controlled
更新于2025-09-23 15:21:01
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Secondary Grain Growth in Organica??Inorganic Perovskite Films with Ethylamine Hydrochloride Additives for Highly Efficient Solar Cells
摘要： The grain boundaries of perovskite polycrystalline are regarded as a defect region that not only provides carrier recombination sites but also introduces device degradation pathways. Efforts to enlarging the grain size of perovskite film and reducing its grain boundary are crucial for highly efficient and stable PSCs. Some effective methods that facilitate grain growth are post-deposition thermal annealing and solvent vapor annealing. However, a detailed understanding of grain growth mechanisms in perovskite films is lacking. In this study, perovskite films were prepared by adding ethylamine hydrochloride (EACl) to the precursor solution. This additive strategy promotes a new grain growth mode, secondary grain growth, in perovskite films. Secondary grain growth leads to much larger grains with high crystallographic orientation. These excellent properties lead to reduced grain boundaries and the densities of boundary defects. The improved film quality results in a prolonged charge–carrier lifetime and a significantly enhanced PCE. Compared with the PCE 18.42% of the control device, the PCE of the device with EACl additives reaches 21.07%.
关键词： Organic-inorganic perovskite,crystallographic orientation,grain growth,power conversion efficiency,solar cells
更新于2025-09-19 17:13:59
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Multiple Resistive Switching Behaviours of CH3NH3PbI3 Perovskite film with Different Metal Electrodes
摘要： The utilization of defects in organic-inorganic hybrid perovskite materials such as CH3NH3PbI3 is beneficial for memory applications. In this work, a simple CH3NH3PbI3 memory device with various commonly used electrodes such as aluminium (Al), silver (Ag), and gold (Au) yielded different switching behaviours. Using Al in ITO/CH3NH3PbI3/Al device reveals Resistive Random Access Memory (ReRAM) behaviour with a SET voltage of 4.5 V and can be RESET by applying a negative sweep voltage above 1.3 V due to the formation of iodide vacancy filament. Interestingly, by using Ag and Au cathodes to replace Al, yielded Write-Once-Read-Many (WORM) resistive switching characteristics. The conversion process from OFF to ON occur at around 4.7 V and 4.0 V for Ag and Au, respectively. The “shorting effect” remains even though a reverse voltage was applied indicating data retention. These fabricated devices could contribute to further understanding of selecting the right electrodes and open up new possibility of studies in the direction of resistive switching memory applications.
关键词： organic-inorganic perovskite,resistive switching,filamentary conduction,charge trapping
更新于2025-09-04 15:30:14