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Photonic devices based on perovskite materials are considered promising alternatives for a wide range of these devices in the future because of their broad bandgaps and ability to contribute to light amplification. The current study investigates the possibility of improving the light amplification characteristics of CsPbBr3 perovskite quantum dot (PQD) films using the surface encapsulation technique. To further amplify emission within a perovskite layer, CsPbBr3 PQD films were sandwiched between two transparent layers of poly(methyl methacrylate) (PMMA) to create a highly flexible PMMA/PQD/PMMA waveguide film configuration. The prepared perovskite film, primed with a polymer layer coating, shows a marked improvement in both emission efficiency and amplified spontaneous emission (ASE)/laser threshold compared with bare perovskite films on glass substrates. Additionally, significantly improved photoluminescence (PL) and long decay lifetime were observed. Consequently, under pulse pumping in a picosecond duration, ASE with a reduction in ASE threshold of ~1.2 and 1.4 times the optical pumping threshold was observed for PQDs of films whose upper face was encapsulated and embedded within a cavity comprising two PMMA reflectors, respectively. Moreover, the exposure stability under laser pumping was greatly improved after adding the polymer coating to the top face of the perovskite film. Finally, this process improved the emission and PL in addition to enhancements in exposure stability. These results were ascribed in part to the passivation of defects in the perovskite top surface, accounting for the higher PL intensity, the slower PL relaxation, and for about 14 % of the ASE threshold decrease.
Saif Qaid; Hamid Ghaithan; Khulod AlHarbi; Bandar Al-Asbahi; Abdullah Aldwayyan. Enhancement of Light Amplification of CsPbBr3 Perovskite Quantum Dot Films via Surface Encapsulation by PMMA Polymer. Polymers 2021, 13, 2574 .
AMA StyleSaif Qaid, Hamid Ghaithan, Khulod AlHarbi, Bandar Al-Asbahi, Abdullah Aldwayyan. Enhancement of Light Amplification of CsPbBr3 Perovskite Quantum Dot Films via Surface Encapsulation by PMMA Polymer. Polymers. 2021; 13 (15):2574.
Chicago/Turabian StyleSaif Qaid; Hamid Ghaithan; Khulod AlHarbi; Bandar Al-Asbahi; Abdullah Aldwayyan. 2021. "Enhancement of Light Amplification of CsPbBr3 Perovskite Quantum Dot Films via Surface Encapsulation by PMMA Polymer." Polymers 13, no. 15: 2574.
Chromium oxide supported on mesoporous organo-silica (MOS) was synthesized with different Cr loading by an incipient method. The catalytic performance of a Cr(x)/MOS catalyst for CO2-based ethane dehydrogenation was investigated. The synthesized catalysts were characterized by XRD, BET, TEM, SEM, XPS, FTIR, and UV–Vis DR measurements. The textural properties of the prepared samples showed that the mesoporous nature of MOS sample was not disturbed by chromium impregnation. Among the prepared samples, Cr(8)/MOS catalyst exhibited good distribution of chromium species along with superior concentration of Cr6+ and the highest recorded Cr6+/Cr3+ ratio. The results revealed that the superior catalytic performance was reached at Cr(8)/MOS, with 50.4% and 90.1% of ethane conversion and ethylene selectivity, respectively. The catalytic activity decreased slowly over reaction time; it declined approximately 22% after 10 h of stream operation. The roles of CO2-based ethane dehydrogenation were also studied, where carbon dioxide can be a source of lattice oxygen and as a hydrogen consumer in reverse water–gas shift (RWGS) reaction. The effect of various catalytic factors, such as catalytic temperature, reaction time, space gas velocity, and CO2 partial pressure on the conversion of ethane, yield, and selectivity to ethylene, were investigated as well.
Abdulrhman Al-Awadi; Ahmed El-Toni; Joselito Labis; Aslam Khan; Hamid Ghaithan; Attiyah Al-Zahrani; Ahmed Abasaeed; Saeed Al-Zahrani. Mesoporous Organo-Silica Supported Chromium Oxide Catalyst for Oxidative Dehydrogenation of Ethane to Ethylene with CO2. Catalysts 2021, 11, 642 .
AMA StyleAbdulrhman Al-Awadi, Ahmed El-Toni, Joselito Labis, Aslam Khan, Hamid Ghaithan, Attiyah Al-Zahrani, Ahmed Abasaeed, Saeed Al-Zahrani. Mesoporous Organo-Silica Supported Chromium Oxide Catalyst for Oxidative Dehydrogenation of Ethane to Ethylene with CO2. Catalysts. 2021; 11 (5):642.
Chicago/Turabian StyleAbdulrhman Al-Awadi; Ahmed El-Toni; Joselito Labis; Aslam Khan; Hamid Ghaithan; Attiyah Al-Zahrani; Ahmed Abasaeed; Saeed Al-Zahrani. 2021. "Mesoporous Organo-Silica Supported Chromium Oxide Catalyst for Oxidative Dehydrogenation of Ethane to Ethylene with CO2." Catalysts 11, no. 5: 642.
Perovskite quantum dots (PQDs) have emerged as promising competitive materials for optoelectronics and future energy applications. In this work, high-quality PQD thin films fabricated directly from the powdered form of CsPb(Br1–xClx)3 compositions were investigated. Tunable light emission was achieved via (in general) composition modulation through a mixed halide (chloride/bromide) with different ratios of Cl-ion substitution of Br ions. The structural properties of the various compositions (alloys) as a function of the Cl content were investigated. These properties were correlated with the emitting colors and amplified spontaneous emission (ASE)/lasing performance, and the potential application of these properties in lighting devices and other optoelectronics devices was verified. These alloys consisted of a highly stable cubic phase that remained stable even at room temperature because of direct synthesis at a high temperature for all compositions. The Cl content had only a slight effect on the QD size. Moreover, the bandgaps of the alloys exhibited a strong dependence on the composition and increased rapidly with changing Br-to-Cl ratio through the halide ion exchange process. Furthermore, compositionally, the perovskite alloy was a photostable material and exhibited excellent photoluminescence quantum yields (PLQYs) and considerable photoluminescence. Alloys with a high Cl content underwent significant nonradiative decay, and the PLQYs decreased with increasing bandgap. These features were all dependent on ligand exchange from Br to Cl. In addition, ASE properties of these composition films were achieved and compared under long-term ambient conditions. Moreover, a low ASE threshold (21, 45, and 53 μJ/cm2 for x = 0, 0.25, and 0.40, respectively) was obtained under picosecond laser excitation.
Saif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. Tuning of Amplified Spontaneous Emission Wavelength for Green and Blue Light Emission through the Tunable Composition of CsPb(Br1–xClx)3 Inorganic Perovskite Quantum Dots. The Journal of Physical Chemistry C 2021, 125, 9441 -9452.
AMA StyleSaif M. H. Qaid, Hamid M. Ghaithan, Bandar Ali Al-Asbahi, Abdullah S. Aldwayyan. Tuning of Amplified Spontaneous Emission Wavelength for Green and Blue Light Emission through the Tunable Composition of CsPb(Br1–xClx)3 Inorganic Perovskite Quantum Dots. The Journal of Physical Chemistry C. 2021; 125 (17):9441-9452.
Chicago/Turabian StyleSaif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. 2021. "Tuning of Amplified Spontaneous Emission Wavelength for Green and Blue Light Emission through the Tunable Composition of CsPb(Br1–xClx)3 Inorganic Perovskite Quantum Dots." The Journal of Physical Chemistry C 125, no. 17: 9441-9452.
The influence of SiO2/TiO2 nanocomposites (STNCs) content on non-radiative energy transfer (Förster-type) from poly (9,9′-dioctylfluorene-2,7-diyl) (PFO) to poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) using steady-state and time-resolved photoluminescence spectroscopies was investigated at room temperature. The improved energy transfer from PFO to MEH-PPV upon an increment of the STNCs was achieved by examining absorbance, emission (PL) and photoluminescence excitation (PLE) spectra. The shorter values of the quantum yield (φDA) and lifetime (τDA) of the PFO in the hybrid thin films compared with the pure PFO, indicating efficient energy transfer from PFO to MEH-PPV with the increment of STNCs in the hybrid. The energy transfer parameters can be tuned by increment of the STNCs in the hybrid of PFO/MEH-PPV. The Stern–Volmer value (kSV), quenching rate value (kq), Förster radius (R0), distance between the molecules of PFO and MEH-PPV (RDA), energy transfer lifetime (τET), energy transfer rate (kET), total decay rate of the donor (TDR), critical concentration (Ao), and conjugation length (Aπ) were calculated. The gradually increasing donor lifetime and decreasing acceptor lifetime, upon increasing the STNCs content, prove the increase in conjugation length and meanwhile enhance in the energy transfer.
Bandar Al-Asbahi; Mohammad Hj. Jumali; M. AlSalhi; Saif Qaid; Amanullah Fatehmulla; Wafa Mujamammi; Hamid Ghaithan. Tuning Photophysical Properties of Donor/Acceptor Hybrid Thin- Film via Addition of SiO2/TiO2 Nanocomposites. Polymers 2021, 13, 611 .
AMA StyleBandar Al-Asbahi, Mohammad Hj. Jumali, M. AlSalhi, Saif Qaid, Amanullah Fatehmulla, Wafa Mujamammi, Hamid Ghaithan. Tuning Photophysical Properties of Donor/Acceptor Hybrid Thin- Film via Addition of SiO2/TiO2 Nanocomposites. Polymers. 2021; 13 (4):611.
Chicago/Turabian StyleBandar Al-Asbahi; Mohammad Hj. Jumali; M. AlSalhi; Saif Qaid; Amanullah Fatehmulla; Wafa Mujamammi; Hamid Ghaithan. 2021. "Tuning Photophysical Properties of Donor/Acceptor Hybrid Thin- Film via Addition of SiO2/TiO2 Nanocomposites." Polymers 13, no. 4: 611.
High-quality inorganic cesium lead halide perovskite quantum dot (CsPbBr3 PQD) thin films were successfully deposited directly from a powdered source and used as an active laser medium following the examination of their distinctive surface and structural properties. To determine the suitability of the CsPbBr3 PQDs as an active laser medium, amplified spontaneous emission (ASE) and optical gain properties were investigated under picosecond pulse excitation using the variable stripe length (VSL) method. The thin film of CsPbBr3 PQDs has exhibited a sufficient value of the optical absorption coefficient of ∼0.86 × 105 cm–1 near the band edge and a direct band gap energy Eg ∼2.38 eV. The samples showed enhanced emission, and ASE was successfully recorded at a low threshold. The light emitted from the edge was observed near 2.40 and 2.33 eV for the stimulated emission (SE) and ASE regimes, respectively. The nonradiative decay contributes excitons dominant over biexcitons in the sample edge emission above the ASE threshold, making it practical for CsPbBr3 PQDs to be used as optical gain media without undergoing repeated SE processes above the threshold over long periods. A high value of the optical gain coefficient was recorded at 346 cm–1.
Saif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. Achieving Optical Gain of the CsPbBr3 Perovskite Quantum Dots and Influence of the Variable Stripe Length Method. ACS Omega 2021, 6, 5297 -5309.
AMA StyleSaif M. H. Qaid, Hamid M. Ghaithan, Bandar Ali Al-Asbahi, Abdullah S. Aldwayyan. Achieving Optical Gain of the CsPbBr3 Perovskite Quantum Dots and Influence of the Variable Stripe Length Method. ACS Omega. 2021; 6 (8):5297-5309.
Chicago/Turabian StyleSaif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. 2021. "Achieving Optical Gain of the CsPbBr3 Perovskite Quantum Dots and Influence of the Variable Stripe Length Method." ACS Omega 6, no. 8: 5297-5309.
The current work examines the effects of cesium lead bromide (CsPbBr3) perovskite quantum dots (PQDs) on the structural and optical properties of conjugated polymer blends of poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylene vinylene] (MEH–PPV) and poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO). MEH–PPV/PFO composite thin‑films containing PQDs with weight ratios between 0.5 wt.% and 10 wt.% were prepared via a solution-blending method prior to spin-coating on glass substrates. The MEH–PPV/PFO composites’ crystallinity was improved, and the roughness was dramatically increased with higher PQDs content, as confirmed by X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. Conversely, a higher PQDs content resulted in a gradual reduction of the Urbach tail and an increase in the steepness parameter, thereby reducing the localized density of the electronic states within the forbidden bandgap of the hybrids. Moreover, a slight reduction in the direct and indirect bandgaps was found in PQDs/(MEH–PPV/PFO) composite films containing a higher PQDs content and provided evidence of the low concentration of the localized states. The incorporation of the PQDs resulted in enhanced non-radiative energy transfer processes in the MEH–PPV/PFO hybrids, which are very important for the development of optimized optoelectronic devices.
Saif M. H. Qaid; Bandar Ali Al-Asbahi; Hamid M. Ghaithan; Abdullah S. Aldwayyan. Tuning the Optical Properties of MEH–PPV/PFO Hybrid Thin Films via the Incorporation of CsPbBr3 Quantum Dots. Coatings 2021, 11, 154 .
AMA StyleSaif M. H. Qaid, Bandar Ali Al-Asbahi, Hamid M. Ghaithan, Abdullah S. Aldwayyan. Tuning the Optical Properties of MEH–PPV/PFO Hybrid Thin Films via the Incorporation of CsPbBr3 Quantum Dots. Coatings. 2021; 11 (2):154.
Chicago/Turabian StyleSaif M. H. Qaid; Bandar Ali Al-Asbahi; Hamid M. Ghaithan; Abdullah S. Aldwayyan. 2021. "Tuning the Optical Properties of MEH–PPV/PFO Hybrid Thin Films via the Incorporation of CsPbBr3 Quantum Dots." Coatings 11, no. 2: 154.
The optical properties of inorganic cesium lead bromide perovskite quantum dots (CsPbBr3-PQDs) make them particularly suitable for use as semiconductors. However, surface defects limit the performance of PQDs-based materials and devices. Consequently, this study investigated a surface passivation approach using a special polymer coating under standard conditions. In encapsulation materials, one of the most critical requirements is that the polymer should possess transparency; optical applications require material transparency to avoid affecting optical properties. Additionally, for optical compatibility, a polymer's refractive indices must be significantly different from those of emission materials, and the polymer should be amorphous. Therefore, this study investigated the basic optical properties and parameters of a polymethyl methacrylate polymer-passivated CsPbBr3-PQDs surface and compared them with a bare CsPbBr3-PQDs surface. Optical properties such as absorbance, transmittance, and reflectance are associated with important optical constants, including bandgap, absorption coefficient, extinction coefficient, refractive index, and dielectric constant. With the surface passivation approach, the surface-modification-dependent optical properties of CsPbBr3-PQDs can suppress surface states and improve the surface quality of PQDs-based materials and devices without optical contribution or structural changes. Surface passivation results in enhanced emission, which is key to improving the performance of PQDs-based optoelectronic devices.
Saif M.H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. Investigation of the Surface Passivation Effect on the Optical Properties of CsPbBr3 Perovskite Quantum Dots. Surfaces and Interfaces 2021, 23, 100948 .
AMA StyleSaif M.H. Qaid, Hamid M. Ghaithan, Bandar Ali Al-Asbahi, Abdullah S. Aldwayyan. Investigation of the Surface Passivation Effect on the Optical Properties of CsPbBr3 Perovskite Quantum Dots. Surfaces and Interfaces. 2021; 23 ():100948.
Chicago/Turabian StyleSaif M.H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. 2021. "Investigation of the Surface Passivation Effect on the Optical Properties of CsPbBr3 Perovskite Quantum Dots." Surfaces and Interfaces 23, no. : 100948.
Several inorganic perovskites of iodine, bromine, and chlorine halides have emerged as candidates for various optoelectronic devices. High-quality CsPb(I1–xBrx)3 and CsPb(Br1–xClx)3 (x = 0.00, 0.25, 0.50, 0.75, and 1.00) inorganic perovskite thin films were prepared in this study using a thermal evaporation system. Experiments and first-principles calculations were conducted to elucidate the structural, electronic, and optical properties of the prepared films at room temperature. The thin-film perovskite band gap was tuned from 1.85 to 3.13 eV by replacing I– with Br– and then Cl–. Dominant excitonic effects on the onset of optical absorption led us to explicitly account for enhancing absorption through the Sommerfield factor, enabling us to extract the electronic band gap and the exciton binding energy correctly. We correlated our experimental results with the theory of first principles and gained insight into the lattice parameters, electronic structure, excitonic binding energy (Eb), dielectric constant (ε), and reduced effective mass (μ) of the carriers. With increasing concentration (x) of Br and Cl, the Eb increased from 39.44 meV for pure CsPbI3 to 63.04 and 96.73 meV for pure CsPbBr3 and CsPbCl3, respectively, because of a decrease in the dielectric constant and the almost constant value of μ at ∼0.051 me. The Urbach energy (EU) was calculated and found to fluctuate between 28 and 77 meV.
Hamid M. Ghaithan; Saif M. H. Qaid; Zeyad A. AlAhmed; Mahmoud Hezam; Andreas Lyras; Mabrook Amer; Abdullah S. Aldwayyan. Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I1–xBrx)3 and CsPb(Br1–xClx)3 Perovskites: Theoretical and Experimental Approaches. The Journal of Physical Chemistry C 2021, 125, 886 -897.
AMA StyleHamid M. Ghaithan, Saif M. H. Qaid, Zeyad A. AlAhmed, Mahmoud Hezam, Andreas Lyras, Mabrook Amer, Abdullah S. Aldwayyan. Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I1–xBrx)3 and CsPb(Br1–xClx)3 Perovskites: Theoretical and Experimental Approaches. The Journal of Physical Chemistry C. 2021; 125 (1):886-897.
Chicago/Turabian StyleHamid M. Ghaithan; Saif M. H. Qaid; Zeyad A. AlAhmed; Mahmoud Hezam; Andreas Lyras; Mabrook Amer; Abdullah S. Aldwayyan. 2021. "Anion Substitution Effects on the Structural, Electronic, and Optical Properties of Inorganic CsPb(I1–xBrx)3 and CsPb(Br1–xClx)3 Perovskites: Theoretical and Experimental Approaches." The Journal of Physical Chemistry C 125, no. 1: 886-897.
High-quality inorganic cesium lead halide perovskite CsPb(Br0.5Cl0.5)3 thin films were successfully achieved through evaporation of the precursors and deposition sequentially by a single-source thermal evaporation system. The different melting points of the precursors were enabled us to evaporate precursors one by one in one trip. The resulting films through its fabrication were smooth and pinhole-free. Furthermore, this technique enabled complete surface coverage by high-quality perovskite crystallization and more moisture stability oppositely of that produce by solution-processed. Then the perovskite films were encapsulated by evaporated a polymethyl methacrylate (PMMA) polymer as a specialized surface passivation approach with various thicknesses. The blue emission, high photoluminescence quantum yield (PLQY), stable, and low threshold of amplified spontaneous emission (ASE) properties of CsPb(Br0.5Cl0.5)3 films in the bulk structure at room temperature were achieved. The effects of the surface-passivation layer and its thickness on the optical response were examined. Detailed analysis of the dependence of ASE properties on the surface passivation layer thickness was performed, and it was determined this achieves performance optimization. The ASE characteristics of bare perovskite thin film were influenced by the incorporation of the PMMA with various thicknesses. The improvement to the surface layer of perovskite thin films compared to that of the bare perovskite thin film was attributed to the combination of thermal evaporation deposition and surface encapsulation. The best results were achieved when using a low PMMA thickness up to 100 nm and reducing the ASE threshold by ~11 μJ/cm2 when compared with free-encapsulation and by ~13 μJ/cm2 when encapsulation occurs at 200 nm or thicker. Compared to the bare CsPb(Br0.5Cl0.5)3, ASE reduced 1.1 times when the PMMA thickness was 100 nm.
Saif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. Single-Source Thermal Evaporation Growth and the Tuning Surface Passivation Layer Thickness Effect in Enhanced Amplified Spontaneous Emission Properties of CsPb(Br0.5Cl0.5)3 Perovskite Films. Polymers 2020, 12, 2953 .
AMA StyleSaif M. H. Qaid, Hamid M. Ghaithan, Bandar Ali Al-Asbahi, Abdullah S. Aldwayyan. Single-Source Thermal Evaporation Growth and the Tuning Surface Passivation Layer Thickness Effect in Enhanced Amplified Spontaneous Emission Properties of CsPb(Br0.5Cl0.5)3 Perovskite Films. Polymers. 2020; 12 (12):2953.
Chicago/Turabian StyleSaif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. 2020. "Single-Source Thermal Evaporation Growth and the Tuning Surface Passivation Layer Thickness Effect in Enhanced Amplified Spontaneous Emission Properties of CsPb(Br0.5Cl0.5)3 Perovskite Films." Polymers 12, no. 12: 2953.
Organic–inorganic halide organometal perovskites have demonstrated very promising performance in optoelectronic applications, but their relatively poor chemical and colloidal stability hampers the further improvement of devices based on these materials. Perovskite material engineering is crucial for achieving high photoluminescence quantum yields (PLQYs) and long stability. Herein, these goals are attained by incorporating bulk-structure CsPbBr3, which prevents colloidal degradation, into polymethyl methacrylate (PMMA) polymer in thin-disk form. This technology can potentially realize future disk lasers with no optical and structural contributions from the polymer. The polycrystalline CsPbBr3 perovskite particles were simply obtained by using a mechanical processing technique. The CsPbBr3 was then incorporated into the PMMA polymer using a solution blending method. The polymer enhanced the PLQYs by removing the surface trap states and increasing the water resistance and stability under ambient conditions. In our experimental investigation, the CsPbBr3/PMMA composites were extraordinarily stable and remained strongly luminescent after water immersion for three months and air exposure for over one year, maintaining 80% of their initial photoluminescence intensity. The CsPbBr3/PMMA thin disk produced amplified spontaneous emission for a long time in air and for more than two weeks in water.
Saif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. Ultra-Stable Polycrystalline CsPbBr3 Perovskite–Polymer Composite Thin Disk for Light-Emitting Applications. Nanomaterials 2020, 10, 2382 .
AMA StyleSaif M. H. Qaid, Hamid M. Ghaithan, Bandar Ali Al-Asbahi, Abdullah S. Aldwayyan. Ultra-Stable Polycrystalline CsPbBr3 Perovskite–Polymer Composite Thin Disk for Light-Emitting Applications. Nanomaterials. 2020; 10 (12):2382.
Chicago/Turabian StyleSaif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdullah S. Aldwayyan. 2020. "Ultra-Stable Polycrystalline CsPbBr3 Perovskite–Polymer Composite Thin Disk for Light-Emitting Applications." Nanomaterials 10, no. 12: 2382.
We developed a facile strategy to construct organic D–π–A dyes via sequential condensation reactions for dye-sensitized solar cells.
Hongjin Chen; Ashraful Islam; Towhid H. Chowdhury; Idriss Bedja; Hamid M. Ghaithan; Rui Zhang; Jian Liu. A facile approach to construct organic D–π–A dyes via sequential condensation reactions for dye-sensitized solar cells. Sustainable Energy & Fuels 2020, 5, 289 -296.
AMA StyleHongjin Chen, Ashraful Islam, Towhid H. Chowdhury, Idriss Bedja, Hamid M. Ghaithan, Rui Zhang, Jian Liu. A facile approach to construct organic D–π–A dyes via sequential condensation reactions for dye-sensitized solar cells. Sustainable Energy & Fuels. 2020; 5 (1):289-296.
Chicago/Turabian StyleHongjin Chen; Ashraful Islam; Towhid H. Chowdhury; Idriss Bedja; Hamid M. Ghaithan; Rui Zhang; Jian Liu. 2020. "A facile approach to construct organic D–π–A dyes via sequential condensation reactions for dye-sensitized solar cells." Sustainable Energy & Fuels 5, no. 1: 289-296.
High-quality thin films were obtained directly by spin-coating glass substrates with suspensions of powdered cesium lead bromide (CsPbBr3) perovskite quantum dots (PQDs). The structural properties of the films were characterized via transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis, and atomic force microscopy (AFM). The crystal structure of the CsPbBr3 PQDs was unique. The optical behavior of the CsPbBr3 PQDs, including absorption and emission, was then investigated to determine the absorption coefficient and band gap of the material. The CsPbBr3 PQDs were evaluated as active lasing media and irradiated with a pulsed laser under ambient conditions. The PQDs were laser-active when subjected to optical pumping for pulse durations of 70–80 ps at 15 Hz. Amplified spontaneous emission (ASE) by the CsPbBr3 PQD thin films was observed, and a narrow ASE band (∼5 nm) was generated at a low threshold energy of 22.25 μJ cm–2. The estimated ASE threshold carrier density (nth) was ∼7.06 × 1018 cm–3. Band-gap renormalization (BGR) was indicated by an ASE red shift and a BGR constant of ∼27.10 × 10–8 eV. A large optical absorption coefficient, photoluminescence (PL), and a substantial optical gain indicated that the CsPbBr3 PQD thin films could be embedded in a wide variety of cavity resonators to fabricate unique on-chip coherent light sources.
Saif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdulaziz Alqasem; Abdullah S. Aldwayyan. Fabrication of Thin Films from Powdered Cesium Lead Bromide (CsPbBr3) Perovskite Quantum Dots for Coherent Green Light Emission. ACS Omega 2020, 5, 30111 -30122.
AMA StyleSaif M. H. Qaid, Hamid M. Ghaithan, Bandar Ali Al-Asbahi, Abdulaziz Alqasem, Abdullah S. Aldwayyan. Fabrication of Thin Films from Powdered Cesium Lead Bromide (CsPbBr3) Perovskite Quantum Dots for Coherent Green Light Emission. ACS Omega. 2020; 5 (46):30111-30122.
Chicago/Turabian StyleSaif M. H. Qaid; Hamid M. Ghaithan; Bandar Ali Al-Asbahi; Abdulaziz Alqasem; Abdullah S. Aldwayyan. 2020. "Fabrication of Thin Films from Powdered Cesium Lead Bromide (CsPbBr3) Perovskite Quantum Dots for Coherent Green Light Emission." ACS Omega 5, no. 46: 30111-30122.
The effect of halide composition on the structural, electronic, and optical properties of CsPb(Br1−xClx)3 perovskite was investigated in this study. When the chloride (Cl) content of x was increased, the unit cell volume decreased with a linear function. Theoretical X-ray diffraction analyses showed that the peak (at 2θ = 30.4°) shifts to a larger angle (at 2θ = 31.9°) when the average fraction of the incorporated Cl increased. The energy bandgap (Eg) was observed to increase with the increase in Cl concentration. For x = 0.00, 0.25, 0.33, 0.50, 0.66, 0.75, and 1.00, the Eg values calculated using the Perdew–Burke–Ernzerhof potential were between 1.53 and 1.93 eV, while those calculated using the modified Becke−Johnson generalized gradient approximation (mBJ–GGA) potential were between 2.23 and 2.90 eV. The Eg calculated using the mBJ–GGA method best matched the experimental values reported. The effective masses decreased with a concentration increase of Cl to 0.33 and then increased with a further increase in the concentration of Cl. Calculated photoabsorption coefficients show a blue shift of absorption at higher Cl content. The calculations indicate that CsPb(Br1−xClx)3 perovskite could be used in optical and optoelectronic devices by partly replacing bromide with chloride.
Hamid M. Ghaithan; Zeyad. A. Alahmed; Saif M. H. Qaid; Abdullah S. Aldwayyan. Structural, Electronic, and Optical Properties of CsPb(Br1−xClx)3 Perovskite: First-Principles Study with PBE–GGA and mBJ–GGA Methods. Materials 2020, 13, 4944 .
AMA StyleHamid M. Ghaithan, Zeyad. A. Alahmed, Saif M. H. Qaid, Abdullah S. Aldwayyan. Structural, Electronic, and Optical Properties of CsPb(Br1−xClx)3 Perovskite: First-Principles Study with PBE–GGA and mBJ–GGA Methods. Materials. 2020; 13 (21):4944.
Chicago/Turabian StyleHamid M. Ghaithan; Zeyad. A. Alahmed; Saif M. H. Qaid; Abdullah S. Aldwayyan. 2020. "Structural, Electronic, and Optical Properties of CsPb(Br1−xClx)3 Perovskite: First-Principles Study with PBE–GGA and mBJ–GGA Methods." Materials 13, no. 21: 4944.
The triplet energy transfer mechanism of novel poly(9,9-di-n-octylflourenyl-2,7-diyl) (PFO)/poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)/CsPbBr3 perovskite quantum dot (PQD) hybrid thin films was comprehensively investigated. The concentrations of PFO and MEH-PPV in all the specimens were fixed, while the PQD content was varied with various weight ratios and premixed by a solution blending method before it was spin-coated onto glass substrates. The triplet non-radiative Förster resonance energy transfers (FRETs) in the PFO/MEH-PPV/PQDs ternary blend, the dual FRET from PFO to both PQDs and MEH-PPV, and the secondary FRET from PQDs to MEH-PPV were observed. The values of the Förster radius (Ro) of FRET from PFO to MEH-PPV in the presence of various PQD contents (Case I) increased from 92.3 to 104.7 Å, and they decreased gradually from 68.0 to 39.5 Å for FRET from PFO to PQDs in the presence of MEH-PPV (Case II). These Ro values in both cases confirmed the dominance of FRET in ternary hybrid thin films. Upon increasing the PQD content, the distance between the donor and acceptor molecules (RDA) and the conjugation length (Aπ) in both cases gradually decreased. The small values of Ro, RDA, and Aπ with a decrease in the energy transfer lifetime (τET) due to an increase in the PQD contents in both Cases I and II confirmed the efficient FRET in the hybrid. To prevent intermolecular transfer in PFO, the concentrations of MEH-PPV (Case I) and PQDs (Case II) should be decreased to a range of 0.57–0.39 mM and increased in the range of 1.42–7.25 mM.
Bandar Al-Asbahi; Saif Qaid; Hamid Ghaithan; Abdullah Aldwayyan. Triplet Energy Transfer Mechanism of Ternary Organic Hybrid Thin Films of PFO/MEH-PPV/CsPbBr3 Perovskite Quantum Dots. Nanomaterials 2020, 10, 2094 .
AMA StyleBandar Al-Asbahi, Saif Qaid, Hamid Ghaithan, Abdullah Aldwayyan. Triplet Energy Transfer Mechanism of Ternary Organic Hybrid Thin Films of PFO/MEH-PPV/CsPbBr3 Perovskite Quantum Dots. Nanomaterials. 2020; 10 (11):2094.
Chicago/Turabian StyleBandar Al-Asbahi; Saif Qaid; Hamid Ghaithan; Abdullah Aldwayyan. 2020. "Triplet Energy Transfer Mechanism of Ternary Organic Hybrid Thin Films of PFO/MEH-PPV/CsPbBr3 Perovskite Quantum Dots." Nanomaterials 10, no. 11: 2094.
The effect of TiO2 nanoparticles on the photophysical properties of ternary conjugated polymer (CP) blends of poly(9,9-dioctylfluorene-2,7-diyl) (PFO), poly 9,9-dioctylfluorene-alt-benzothiadiazole (F8BT) and poly(2-methoxy-5(2-ethylhexyl)-1,4 -phenylenevinylene (MEH-PPV) thin films was investigated. This ternary blend used a fixed amount of PFO as the donor with MEH-PPV and F8BT in various ratios as the acceptors. The solution-blending method and the spin-coating technique were used to prepare the blends and the thin films, respectively. Through efficient Förster Resonance Energy Transfer (FRET), the desired white emission was achieved with PFO/0.3 wt.% F8BT/0.5 wt.% MEH-PPV ternary blend thin film. Additions of nanoparticles up to 10 wt.% dramatically intensified the white emission which then dimmed at higher contents due to agglomerations. The current density–voltage characteristics of the nanocomposite thin films exhibited dependency on the content and distributions of the nanoparticles. Finally, a possible underlying mechanism for the intensification of emission is proposed.
Sameer Al-Bati; Mohammad Hafizuddin Hj. Jumali; Bandar Ali Al-Asbahi; Khatatbeh Ibtehaj; Chi Chin Yap; Saif M. H. Qaid; Hamid M. Ghaithan; W. A. Farooq. Improving Photophysical Properties of White Emitting Ternary Conjugated Polymer Blend Thin Film via Additions of TiO2 Nanoparticles. Polymers 2020, 12, 2154 .
AMA StyleSameer Al-Bati, Mohammad Hafizuddin Hj. Jumali, Bandar Ali Al-Asbahi, Khatatbeh Ibtehaj, Chi Chin Yap, Saif M. H. Qaid, Hamid M. Ghaithan, W. A. Farooq. Improving Photophysical Properties of White Emitting Ternary Conjugated Polymer Blend Thin Film via Additions of TiO2 Nanoparticles. Polymers. 2020; 12 (9):2154.
Chicago/Turabian StyleSameer Al-Bati; Mohammad Hafizuddin Hj. Jumali; Bandar Ali Al-Asbahi; Khatatbeh Ibtehaj; Chi Chin Yap; Saif M. H. Qaid; Hamid M. Ghaithan; W. A. Farooq. 2020. "Improving Photophysical Properties of White Emitting Ternary Conjugated Polymer Blend Thin Film via Additions of TiO2 Nanoparticles." Polymers 12, no. 9: 2154.
This paper reports the preparation of cadmium sulfide (CdS) thin films using a nebulizer spray pyrolysis technique by varying gadolinium content in the range of 0–5 wt.%; their characterization is also described. In this study, the effect of Gd concentration on structure, vibrational, optical linear, and nonlinear properties is investigated. The XRD examination of undoped and Gd-doped CdS films shows the crystalline nature toward the (002) plane. Other important parameters, such as crystalline size (D), strain (ɛ), and dislocations density (δ), were evaluated by XRD, and these results are thoroughly discussed. The SEM studies show the morphology of grains. It was observed that the size of grains increased with an increase in doping concentration. Owing to Gd doping in CdS, the optical energy gap is observed to be lower than that of pure film, which is in the range of 2.416–2.283 eV. The linear and nonlinear properties of CdS: Gd films indicated that Gd doping affected optical properties. The observed enhancement in opto-electrical properties, changes in crystalline quality, and optical property enhancements are caused by an increase in Gd doping concentration.
Mohd Shkir; Kamlesh V. Chandekar; Aslam Khan; Ahmed Mohamed El-Toni; I.M. Ashraf; M. Benghanem; Syed Farooq Adil; Anees A. Ansari; Hamid M. Ghaithan; S. AlFaify. Structural, morphological, vibrational, optical, and nonlinear characteristics of spray pyrolyzed CdS thin films: Effect of Gd doping content. Materials Chemistry and Physics 2020, 255, 123615 .
AMA StyleMohd Shkir, Kamlesh V. Chandekar, Aslam Khan, Ahmed Mohamed El-Toni, I.M. Ashraf, M. Benghanem, Syed Farooq Adil, Anees A. Ansari, Hamid M. Ghaithan, S. AlFaify. Structural, morphological, vibrational, optical, and nonlinear characteristics of spray pyrolyzed CdS thin films: Effect of Gd doping content. Materials Chemistry and Physics. 2020; 255 ():123615.
Chicago/Turabian StyleMohd Shkir; Kamlesh V. Chandekar; Aslam Khan; Ahmed Mohamed El-Toni; I.M. Ashraf; M. Benghanem; Syed Farooq Adil; Anees A. Ansari; Hamid M. Ghaithan; S. AlFaify. 2020. "Structural, morphological, vibrational, optical, and nonlinear characteristics of spray pyrolyzed CdS thin films: Effect of Gd doping content." Materials Chemistry and Physics 255, no. : 123615.
Lead free CsBi3I10 based thin films has been developed for perovskite solar cells by introducing antisolvent method with photo conversion efficiency up to 740 nm.
Pandiyarajan Mariyappan; Towhid Hossain Chowdhury; Shanthi Subashchandran; Idriss Bedja; Hamid M. Ghaithan; Ashraful Islam. Fabrication of lead-free CsBi3I10 based compact perovskite thin films by employing solvent engineering and anti-solvent treatment techniques: an efficient photo-conversion efficiency up to 740 nm. Sustainable Energy & Fuels 2020, 4, 1 .
AMA StylePandiyarajan Mariyappan, Towhid Hossain Chowdhury, Shanthi Subashchandran, Idriss Bedja, Hamid M. Ghaithan, Ashraful Islam. Fabrication of lead-free CsBi3I10 based compact perovskite thin films by employing solvent engineering and anti-solvent treatment techniques: an efficient photo-conversion efficiency up to 740 nm. Sustainable Energy & Fuels. 2020; 4 (10):1.
Chicago/Turabian StylePandiyarajan Mariyappan; Towhid Hossain Chowdhury; Shanthi Subashchandran; Idriss Bedja; Hamid M. Ghaithan; Ashraful Islam. 2020. "Fabrication of lead-free CsBi3I10 based compact perovskite thin films by employing solvent engineering and anti-solvent treatment techniques: an efficient photo-conversion efficiency up to 740 nm." Sustainable Energy & Fuels 4, no. 10: 1.
The structural, electronic, and optical properties of inorganic CsPb(I1−xBrx)3 compounds were investigated using the full-potential linear augmented-plane wave (FP-LAPW) scheme with a generalized gradient approximation (GGA). Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA) and modified Becke–Johnson GGA (mBJ-GGA) potentials were used to study the electronic and optical properties. The band gaps calculated using the mBJ-GGA method gave the best agreement with experimentally reported values. CsPb(I1−xBrx)3 compounds were wide and direct band gap semiconductors, with a band gap located at the M point. The spectral weight (SW) approach was used to unfold the band structure. By substituting iodide with bromide, an increase in the band gap energy (Eg) values of 0.30 and 0.55 eV, using PBE-GGA and mBJ-GGA potentials, respectively, was observed, whereas the optical property parameters, which were also investigated, demonstrated the reverse effect. The high absorption spectra in the ultraviolet−visible energy range demonstrated that CsPb(I1−xBrx)3 perovskite could be used in optical and optoelectronic devices by partly replacing iodide with bromide.
Hamid M. Ghaithan; Zeyad A. AlAhmed; Andreas Lyras; Saif M. H. Qaid; Abdullah S. Aldwayyan. Computational Investigation of the Folded and Unfolded Band Structure and Structural and Optical Properties of CsPb(I1−xBrx)3 Perovskites. Crystals 2020, 10, 342 .
AMA StyleHamid M. Ghaithan, Zeyad A. AlAhmed, Andreas Lyras, Saif M. H. Qaid, Abdullah S. Aldwayyan. Computational Investigation of the Folded and Unfolded Band Structure and Structural and Optical Properties of CsPb(I1−xBrx)3 Perovskites. Crystals. 2020; 10 (5):342.
Chicago/Turabian StyleHamid M. Ghaithan; Zeyad A. AlAhmed; Andreas Lyras; Saif M. H. Qaid; Abdullah S. Aldwayyan. 2020. "Computational Investigation of the Folded and Unfolded Band Structure and Structural and Optical Properties of CsPb(I1−xBrx)3 Perovskites." Crystals 10, no. 5: 342.
In this study, methyl ammonium lead Iodide perovskite (CH3NH3PbI3≡MAPbI3) was deposited as a thin planar film on a glass substrate at room temperature using one-step and two-step methods. The effect of each method of preparation on the structural, morphological, and optical properties was investigated. The results show that the average size of the MAPbI3 crystallites are ~57.3 nm and 25.8 nm for the one and two-step methods, respectively. The pore-filling of the perovskite film is incomplete when using the one-step process but completely filled when two-step method was used. Therefore, both one-step and two-step methods lead to perovskite islands and void-free perovskite layers, respectively. Scanning emission microscopy images show that the quality of the film produced by two-step is much better than that formed via one-step. Moreover, the perovskite film prepared via one-step method tends to produce a higher pinhole density than two-step, and thus lower coverage that leads to a low absorption and a low absorption coefficient. Parameters such as optical absorption coefficient, refractive index, extinction coefficient, dielectric constant, and optical conductivity were also estimated. The intensities of both photoluminescence and amplified spontaneous emission spectra of MAPbI3 sample prepared via one-step method were found to be lower than those prepared via two-step.
Bandar Ali Al-Asbahi; Saif M.H. Qaid; Mahmoud Hezam; Idriss Bedja; Hamid M. Ghaithan; Abdullah S. Aldwayyan. Effect of deposition method on the structural and optical properties of CH3NH3PbI3 perovskite thin films. Optical Materials 2020, 103, 109836 .
AMA StyleBandar Ali Al-Asbahi, Saif M.H. Qaid, Mahmoud Hezam, Idriss Bedja, Hamid M. Ghaithan, Abdullah S. Aldwayyan. Effect of deposition method on the structural and optical properties of CH3NH3PbI3 perovskite thin films. Optical Materials. 2020; 103 ():109836.
Chicago/Turabian StyleBandar Ali Al-Asbahi; Saif M.H. Qaid; Mahmoud Hezam; Idriss Bedja; Hamid M. Ghaithan; Abdullah S. Aldwayyan. 2020. "Effect of deposition method on the structural and optical properties of CH3NH3PbI3 perovskite thin films." Optical Materials 103, no. : 109836.
Cesium lead bromide (CsPbBr3) perovskite has recently gained significance owing to its rapidly increasing performance when used for light-emitting devices. In this study, we used density functional theory to determine the structural, electronic, and optical properties of the cubic, tetragonal, and orthorhombic temperature-dependent phases of CsPbBr3 perovskite using the full-potential linear augmented plane wave method. The electronic properties of CsPbBr3 perovskite have been investigated by evaluating their changes upon exerting spin-orbit coupling (SOC). The following exchange potentials were used: the local density approximation (LDA), Perdew–Burke–Ernzerhof generalized gradient approximation (PBE-GGA), Engel–Vosko GGA (EV-GGA), Perdew–Burke–Ernzerhof GGA revised for solids (PBEsol-GGA), modified Becke–Johnson GGA (mBJ-GGA), new modified Becke–Johnson GGA (nmBJ-GGA), and unmodified Becke–Johnson GGA (umBJ-GGA). Our band structure results indicated that the cubic, tetragonal, and orthorhombic phases have direct energy bandgaps. By including the SOC effect in the calculations, the bandgaps computed with mBJ-GGA and nmBJ-GGA were found to be in good agreement with the experimental results. Additionally, despite the large variations in their lattice constants, the three CsPbBr3 phases possessed similar optical properties. These results demonstrate a wide temperature range of operation for CsPbBr3.
Hamid M. Ghaithan; Zeyad A. AlAhmed; Saif M. H. Qaid; Mahmoud Hezam; Abdullah S. Aldwayyan. Density Functional Study of Cubic, Tetragonal, and Orthorhombic CsPbBr3 Perovskite. ACS Omega 2020, 5, 7468 -7480.
AMA StyleHamid M. Ghaithan, Zeyad A. AlAhmed, Saif M. H. Qaid, Mahmoud Hezam, Abdullah S. Aldwayyan. Density Functional Study of Cubic, Tetragonal, and Orthorhombic CsPbBr3 Perovskite. ACS Omega. 2020; 5 (13):7468-7480.
Chicago/Turabian StyleHamid M. Ghaithan; Zeyad A. AlAhmed; Saif M. H. Qaid; Mahmoud Hezam; Abdullah S. Aldwayyan. 2020. "Density Functional Study of Cubic, Tetragonal, and Orthorhombic CsPbBr3 Perovskite." ACS Omega 5, no. 13: 7468-7480.