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Solvent-Assisted Tuning the Size and Shape of CsPbBr3 Nanocrystals via Re-Dispersion Process at Ambient Condition
摘要： All-inorganic CsPbBr3 perovskite nanocrystals are emerging as a new class of semiconductors with outstanding optoelectronic properties and great potential for various applications, such as, lasing, photon detection, photovoltaics etc. This article provides the effect of solvents on the re-precipitation of CsPbBr3 perovskite at room temperature. The results observed for CsPbBr3 perovskite in various anti-solvent showed various cubes (nano to micro size), self-assembly of nanocubes and nanorods. In addition, all the various size (nano to micro), self-assembly of nanocubes and shape-controlled nanorods exhibited band-gap tuning at the green light region. The corresponding microscopy (FE-SEM and HR-TEM) images and photoluminescence quantum yield as well as lifetime decay are presented. To the best of our literature knowledge this is the first report on various solvent assisted studies on CsPbBr3 perovskite nanocrystals.
关键词： CsPbBr3 Nanocrystals,nanocubes,effect of solvents,lifetime decay,nanorods,self-assembly
更新于2025-09-10 09:29:36
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Aqueous synthesis of lead halide perovskite nanocrystals with high water stability and bright photoluminescence
摘要： Lead halide perovskites nanocrystals (NCs) have attracted intense attentions because of their excellent optoelectronic properties. The ionic nature of halide perovskites makes them highly vulnerable to water. Encapsulation of perovskite NCs with inorganic or organic materials have been reported to enhance the stability, however they often suffer from large aggregation size, low water-solubility and difficulty for further surface functionalization. Here, we report a facile aqueous process to synthesize water-soluble CsPbBr3/Cs4PbBr6 NCs with the assistance of fluorocarbon agent, which features a novel mechanism of the perovskite crystallization at oil/water interface and direct perovskite NCs/fluorocarbon agent self-assembly in aqueous environment. The products exhibit a high absolute photoluminescence quantum yield (PLQY) of ~80% in water with the photoluminescence lasting for weeks. Through successive ionic layer adsorption and reaction (SILAR), BaSO4 was further applied to encapsulate the NCs, and greatly enhanced their stability in phosphate buffered saline solutions. The high stability in water and saline solution, high PLQY and tunable emission wavelength, together with the successful demonstration of brain tissue labelling and photoluminescence under X-ray excitation, make our perovskite NCs a promising choice for X-ray fluorescent bio-labels.
关键词： CsPbBr3,water soluble,multicolor,perovskite,nanocrystals
更新于2025-09-09 09:28:46
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Rationalizing and Controlling the Surface Structure and Electronic Passivation of Cesium Lead Halide Nanocrystals
摘要： Colloidal lead halide perovskite nanocrystals (NCs) have recently emerged as versatile photonic sources. Their processing and luminescent properties are challenged by the lability of their surfaces, i.e. the interface of the NC core and the ligand shell. On the example of CsPbBr3 NCs, we model the nanocrystal surface structure and its effect on the emergence of trap states using density functional theory. We rationalize the typical observation of a degraded luminescence upon aging or the luminescence recovery upon post-synthesis surface treatments. The conclusions are corroborated by the elemental analysis. We then propose a strategy for healing the surface trap states and for improving the colloidal stability by the combined treatment with didodecyldimethyl ammonium bromide and lead bromide and validate this approach experimentally. This simple procedure results in robust colloids, which are both highly pure and exhibit high photoluminescence quantum yields of up to 95-98%, retained even after 3-4 rounds of washing.
关键词： trap states,didodecyldimethyl ammonium bromide,luminescence recovery,photoluminescence quantum yields,lead bromide,CsPbBr3 NCs,density functional theory,Colloidal lead halide perovskite nanocrystals,surface structure
更新于2025-09-09 09:28:46
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Boosting the efficiency of carbon-based planar CsPbBr3 perovskite solar cells by a modified multistep spin-coating technique and interface engineering
摘要： All-inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted tremendous attentions in the photovoltaic field these days in view of their outstanding stability, especially thermal stability. However, the bromide-rich perovskite, such as CsPbBr3, always suffer from a low phase-purity and poor morphology synthesized by traditional two-step deposition route. Herein, we demonstrate a facile multistep spin-coating strategy to fabricate high-quality CsPbBr3 films on the low-temperature processed compact TiO2 (c-TiO2) electron transport layer (ETL) of the carbon-based PSCs. As-prepared films exhibit more homogeneous with higher CsPbBr3-phase purity and larger average grain sizes up to 1 μm, compared to those prepared through traditional two-step deposition process. The champion power conversion efficiency (PCE) of the planar CsPbBr3 PSC is boosted from 7.05% to 8.12%, getting an increase by 15.2%, due to the increased crystallinity and light-harvesting ability as well as reduced trap states of the CsPbBr3 film. To further enhance the device performance, a SnO2 thin layer with much higher carrier mobility than TiO2 is introduced to passivate the c-TiO2 ETL. It is found that the SnO2 layer can not only improve the surface morphology of the ETL, but also reduce the current shunting pathways in the c-TiO2. The TiO2/SnO2 bilayered ETL possesses a superior electron extraction capability, beneficial to the charge transport and suppression of the interfacial trap-assisted recombination. The best-performing TiO2/SnO2-based CsPbBr3 PSC delivers an excellent fill factor of 0.817 and a high PCE of 8.79%, which is the highest efficiency for planar CsPbBr3 PSCs reported to date. More importantly, the unencapsulated all-inorganic PSCs show a promising humidity and thermal stability with no decline in efficiency when stored in ambient air at room temperature (25 oC) for over 1000 h and 60 oC for one month, respectively. Our work pave the ways for practical applications of cost-effective, highly efficient and stable all-inorganic PSCs.
关键词： carbon-based,TiO2/SnO2,low cost,CsPbBr3,multistep spin-coating,high efficiency and stability
更新于2025-09-09 09:28:46