Publications by authors named "Muhammad Amin Padhiar"

4 Publications

  • Page 1 of 1

Tuning optical properties of CsPbBr3 by mixing Nd3+trivalent lanthanide halide cations for blue light emitting devices.

Nanotechnology 2022 Jan 13. Epub 2022 Jan 13.

Department of Physics, COMSATS Institute of Information Technology, Center for Micro and Nano Devices, Park Road, Islamabad, 44000, PAKISTAN.

In recent years, significant progress has been made in the red and green perovskite quantum dots (PQDs) based light-emitting devices. However, a scarcity of blue-emitting devices that are extremely efficient precludes their research and development for optoelectronic applications. Taking advantage of tunable bandgaps of PQDs over the entire visible spectrum, herein we tune optical properties of CSPbBr3 by mixing Nd3+ trivalent lanthanide halide cations for blue light-emitting devices. The CsPbBr3 PQDs doped with Nd3+ trivalent lanthanide halide cations emitted strong photoemission from green into the blue region. By adjusting their doping concentration, a tunable wavelength from (515 nm) to (450 nm) was achieved with FWHM from (37.83 nm) to (16.6 nm). We simultaneously observed PL linewidth broadening thermal quenching of PL and the blue shift of the optical bandgap from temperature-dependent PL studies. The Nd3+ cations into CsPbBr3 PQDs more efficiently reduced non-radiative recombination. As a result of the efficient removal of defects from PQDs, the photoluminescence quantum yield (PLQY) has been significantly increased to 91% in the blue-emitting region. Significantly, Nd3+ PQDs exhibit excellent long-term stability against the external environment, including water, temperature, and ultraviolet light irradiation. Moreover, we successfully transformed Nd3+ doped PQDs into highly fluorescent nanocomposites. Incorporating these findings, we fabricate and test a stable blue light-emitting LED with EL emission at (462 nm), (475 nm), and successfully produce white light emission from Nd3+ doped nanocomposites with a CIE at (0.32, 0.34), respectively. The findings imply that low-cost Nd3+ doped perovskites may be attractive as light converters in LCDs with a broad color gamut.
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http://dx.doi.org/10.1088/1361-6528/ac4b2eDOI Listing
January 2022

Trioctylphosphine-Assisted Pre-protection Low-Temperature Solvothermal Synthesis of Highly Stable CsPbBr/TiO Nanocomposites.

J Phys Chem Lett 2021 Apr 13;12(15):3786-3794. Epub 2021 Apr 13.

Centre for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Islamabad 44500, Pakistan.

Lead halide perovskite quantum dots (PQDs) are reported as a promising branch of perovskites, which have recently emerged as a field in luminescent materials research. However, before the practical applications of PQDs can be realized, the problem of poor stability has not yet been solved. Herein, we propose a trioctylphosphine (TOP)-assisted pre-protection low-temperature solvothermal synthesis of highly stable CsPbBr/TiO nanocomposites. Due to the protection of branched ligands and the lower temperature of shell formation, these TOP-modified CsPbBr PQDs are successfully incorporated into a TiO monolith without a loss of fluorescence intensity. Because the excellent nature of both parent materials is preserved in CsPbBr/TiO nanocomposites, it is found that the as-prepared CsPbBr/TiO nanocomposites not only display excellent photocatalytic activity but also yield improved PL stability, enabling us to build highly stable white light-emitting diodes and to photodegrade rhodamine B.
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http://dx.doi.org/10.1021/acs.jpclett.1c00693DOI Listing
April 2021

A versatile approach for shape-controlled synthesis of ultrathin perovskite nanostructures.

Dalton Trans 2021 Mar;50(9):3308-3314

Centre for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Islamabad, 44500, Pakistan.

Very recently, ultrathin perovskite nanostructures, with the advantages of perovskite and ultrathin properties, have received an enormous level of interest due to their many fascinating properties, such as a strong quantum confinement effect and a large specific surface area. In spite of this incredible success of perovskite nanocrystals (NCs), the development of perovskite NCs is still in its infancy, and the production of high-quality ultrathin perovskite nanostructures has been a hot topic in the fields of nanoscience and nanotechnology. Herein, we demonstrate that ultrathin CsPbBr3 perovskite nanosheets (NSs) can be obtained by a simple mixing of precursor-ligand complexes under ambient conditions. It was found that the formation of NSs is ascribed to the stepwise self-assembly of the initially formed different types of ultrathin nanostructures. Due to the disappearance of grain boundaries and protection of branched ligands, these NSs exhibit enhanced optical properties compared to other types of samples. This direct synthesis method opens up a promising road for the synthesis of ultrathin NSs and guides the fabrication of other ultrathin nanostructures.
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http://dx.doi.org/10.1039/d0dt04203jDOI Listing
March 2021

Pressure-Driven Transformation of CsPbBrI Nanoparticles into Stable Nanosheets in Solution through Self-Assembly.

J Phys Chem Lett 2020 Nov 10;11(22):9862-9868. Epub 2020 Nov 10.

Belarusian State University of Informatics and Radioelectronics, P. Browki St. 6, 220013 Minsk, Belarus.

Very recently, two-dimensional (2D) perovskite nanosheets (PNSs), taking the advantages of perovskite as well as the 2D structure properties, have received an enormous level of interest throughout the scientific community. In spite of this incredible success in perovskite nanocrystals (NCs), self-assembly of many nanostructures in metal halide perovskites has not yet been realized, and producing highly efficient red-emitting PNSs remains challenging. In this Letter, we show that by using CsPbBrI perovskite nanoparticles (NPs) as a building block, PNSs can emerge spontaneously under high ambient pressure via template-free self-assembly without additional complicated operation. It is found that the formation of PNSs is ascribed to the high pressure that provides the driving force for the alignment of NPs in solution. Because of the disappearance of the grain boundaries between the adjacent NPs and increased crystallinity, these PNSs self-assembled from NPs exhibit enhanced properties compared to the initial NPs, including higher PL intensity and remarkable chemical stability toward light and water.
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http://dx.doi.org/10.1021/acs.jpclett.0c02747DOI Listing
November 2020
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