CHNHPbBr perovskite nanocrystals (NCs) suffer from poor stability because of their high sensitivity to environmental moisture and water. To solve this problem, previous works mainly focus on embedding perovskite NCs into water-resistant matrix to form large composites (size of microns or larger). As an alternative solution without serious changing of NC size, enhancing the stability of perovskite NCs themselves by ligand engineering is rarely reported. In this work, we used hyperbranched polyamidoamine (PAMAM) dendrimers with two different generations (G0 and G4) to synthesize CHNHPbBr perovskite NCs with high photoluminescence (PL) quantum yields (QY) above 70% and a new record stability. A novel dendrimers generation-dependent stability of perovskite NCs was observed. The water-resistance time is 18 h (27 h) for perovskite NCs capped by G0 (G4) generation of PAMAM, which is 7 times (11 times) longer than that of traditional oleic acid-capped NCs. Similar PAMAM generation-related stability is also observed in moisture-resistance tests. The stability time against moisture is 500 h (800 h) for G0 (G4) generation of PAMAM-capped perovskite NCs, which is a new record stability time against moisture for CHNHPbBr perovskite NCs. In addition, our results also indicate that PAMAM ligands outside perovskite NCs can dramatically slow down the speed of halide exchange. Even for the mixture of perovskite NCs with two different halide composition, the original luminescence properties of PAMAM-capped perovskite NCs can retain after mixing. In view of slow halide exchange speed, excellent water and moisture stability, PAMAM dendrimers-capped perovskite NCs and their mixture are available as color conversion single layer in fabrication of light-emitting diodes (LED).
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http://dx.doi.org/10.1088/1361-6528/aab93b | DOI Listing |
Anal Chem
January 2025
Key Laboratory of Optic-Electric Sensing and Analytical Chemistry for Life Science, MOE; College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042, PR China.
ACS Nano
January 2025
Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, LIFM, GBRCE for Functional Molecular Engineering, School of Chemistry, IGCME, Sun Yat-Sen University, Guangzhou 510275, China.
Lead halide perovskite nanocrystal materials such as CsPbX (X = Cl, Br, and I) have triggered an intense research upsurge due to their excellent scintillation performance. Herein, an crystallization strategy is developed to grow CsPbBr nanocrystals (NCs) within a low-melting-point (280 °C) coordination polymer (CP) glass. The viscosity of coordination glass is reduced through a low-temperature (e.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain.
So far, the striking sign reversal in the near-ambient slope of the gap temperature dependence of colloidal CsPbCl perovskite nanocrystals (NCs) compared to its Br counterpart remains unresolved. Pure bromide NCs exhibit a linear gap increase with increasing temperature, to which thermal expansion and electron-phonon interaction equally contribute. In contrast, the temperature slope for the chlorine compound gap is clearly negative.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi'an, 710072, P. R. China.
Mn ions doped CsPbCl perovskite nanocrystals (NCs) exhibit superiority of spin-associated optical and electrical properties. However, precisely controlling the doping concentration, doping location, and the mono-distribution of Mn ions in the large-micro-size CsPbCl perovskite host is a formidable challenge. Here, the micro size CsPbCl perovskite crystals (MCs) are reported with uniform Mn ions doping by self-assembly of Mn ions doped CsPbCl perovskite NCs.
View Article and Find Full Text PDFChem Asian J
January 2025
JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research, New Chemistry Unit, Jakkur, 560064, Bangalore, INDIA.
This study investigates the photophysical behaviour of Mn/Fe and Mn/Sn co-doped CsPbCl3 perovskite nanocrystals (NCs) to explore carrier dynamics and dopant interactions. Using gated photoluminescence (PL) and temperature-dependent measurements, we elucidate the impact of dopant chemistry on exciton behaviour, focusing on vibrationally assisted delayed fluorescence (VADF) and energy transfer mechanisms. The efficiency of VADF is influenced by factors such as the bandgap, temperature, quantum confinement, and host composition.
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