Enhancement of optical properties of poly (9,9′-di-n-octylfluorenyl-2,7-diyl) in conjugated polymer/TiO2 nanocomposites

2014 ◽  
Vol 92 (9) ◽  
pp. 1021-1025 ◽  
Author(s):  
Bandar Ali Al-Asbahi ◽  
Mohammad Hafizuddin Haji Jumali
Keyword(s):  
Optical Properties ◽  
Conjugated Polymer ◽  
Emission Spectra ◽  
Treatment Temperature ◽  
Nanocomposite Films ◽  
Glass Substrates ◽  
Solution Blending ◽  
Heat Treated ◽  
Blending Method ◽  
Splitting Energy

The influence of colloidal TiO2 nanoparticle contents on the optical properties of poly (9,9′-di-n-octylfluorenyl-2,7-diyl) conjugated polymer (PFO) has been investigated. The solution blending method was used to prepare homogenous PFO/TiO2 nanocomposite. The nanocomposite films were prepared on glass substrates using the spin-coating technique. The films were divided into two groups, the first was left to dry at room temperature while the second was heat-treated at 120 °C for 1 h. Absorption and emission spectra showed that the PFO existed in α- and β-phases morphology having monomeric, excimeric, and double excimeric states. In addition, both spectra revealed that TiO2 contents and heat treatment temperature extended the conjugation length of PFO. Finally, emission spectra for both cases exhibited decreasing in the line width of zero-phonon emission spectra and increasing in the vibronic splitting energy, upon increment of the TiO2, led to a significant increase in π-electron delocalization and lower degree in chain disorder.

scholarly journals Tuning the Optical Properties of MEH–PPV/PFO Hybrid Thin Films via the Incorporation of CsPbBr3 Quantum Dots

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 154
Author(s):  
Saif M. H. Qaid ◽  
Bandar Ali Al-Asbahi ◽  
Hamid M. Ghaithan ◽  
Abdullah S. Aldwayyan
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Optical Properties ◽  
Composite Films ◽  
Localized States ◽  
Radiative Energy ◽  
Slight Reduction ◽  
Glass Substrates ◽  
Solution Blending ◽  
Blending Method

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.

Modification of Optophysical Properties of Poly[(9,9-Di-N-Octylfluorenyl-2,7-Diyl)-Alt-(Benzo[2,1,3]Thiadiazol-4,8-Diyl)] Thin Film via Additions of TiO2 Nanoparticles

2017 ◽  
Vol 888 ◽  
pp. 357-361
Author(s):  
Siti Aishah Ahmad Fuzi ◽  
Mohammad Hafizuddin Hj Jumali ◽  
Bandar Ali Al-Asbahi ◽  
Kuan Ying Kok ◽  
Nur Ubaidah Saidin
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
Emission Spectrum ◽  
Polymer Matrix ◽  
Energy Band ◽  
Intermediate Energy ◽  
Absorption Properties ◽  
Glass Substrates ◽  
Solution Blending ◽  
Vis Spectroscopy

The solution of poly [(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo [2,1,3] thiadiazol-4,8-diyl)] (F8BT) F8BT/TiO2 nanocomposites were prepared using solution blending methods. The TiO2 contents were fixed between 0 wt% - 35 wt%. Then, the solutions were spin coated at 1000 rpm for 30 s onto glass substrates to form thin film samples. The optical properties of the nanocomposites were determined using UV-Vis spectroscopy and photoluminescence spectroscopy. The absorption properties of the thin film increased due to existence of intermediate energy band which lead to higher space charge regions for electron insertion. Besides that, the λmax for absorption and emission spectrum were systematically shifted due to incorporation of TiO2 NPs indicating an interaction between nanoparticles and polymer matrix. Furthermore, the intensity of the emission spectrum were enhanced in the presence of TiO2 NPs. This is due to the existence of TiO2 NPs which trapped more electrons at the interface F8BT/TiO2, resulted production of higher number of exciton formation in the nanocomposirte samples.

Enhancement of Poly(9,9'-di-n-octylfluorenyl-2.7-diyl) Optoelectronic Properties in Novel Conjugated Polymer/Laser Dye Hybrid OLEDs

2013 ◽  
Vol 756 ◽  
pp. 281-288 ◽  
Author(s):  
Bandar Ali Al-Asbahi ◽  
Mohammad Hafizuddin Haji Jumali ◽  
Chi Chin Yap ◽  
Muhamad Mat Salleh
Keyword(s):  
Energy Transfer ◽  
Indium Tin Oxide ◽  
Conjugated Polymer ◽  
Average Distance ◽  
Optoelectronic Properties ◽  
Laser Dye ◽  
Efficient Energy Transfer ◽  
Solution Blending ◽  
Blending Method ◽  
Donor And Acceptor

The effect of laser dye (Fluorol 7GA) content on the optoelectronic properties of Poly ( 9,9'-di-n-octylfluorenyl-2.7-diyl) conjugated polymer (PFO) based OLEDs has been investigated. The PFO/Fluorol 7GA hybrids with weight ratios between 0.1 and 5 wt. % were prepared using the solution blending method. The blends were deposited on ITO (Indium Tin Oxide) substrate using spin-coating technique. Thin layer of aluminum was deposited on top of the films to act as electrode. Absorption and photoluminescence techniques were used to investigate the energy transfer in the blend. The device performance was investigated in terms of electroluminescence, luminance, luminance efficiency and color measurements. The Förster energy transfer occurred in the blends as evidence from optical spectroscopy and average distance between donor and acceptor molecules. The optimum ratio was 0.5 wt. % where highest enhancement in OLEDs performance was observed. These were attributed to the synchronize effect of efficient energy transfer from PFO to Fluorol 7GA and carrier trapping processes.

scholarly journals Efficient Charge Transfer Mechanism in Polyfluorene/ZnO Nanocomposite Thin Films

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Bandar Ali Al-Asbahi ◽  
Mohammad Hafizuddin Haji Jumali ◽  
Rashad Al-Gaashani
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Charge Transfer ◽  
Zno Nanorods ◽  
Transfer Mechanism ◽  
Nanocomposite Films ◽  
Charge Transfer Mechanism ◽  
Blending Method ◽  
Nanocomposite Thin Films ◽  
Efficient Charge

The optical properties and charge transfer mechanism of poly (9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO)/ZnO thin films have been investigated. The ZnO nanorods (NRs) were prepared via a microwave technique. The solution blending method was used to prepare the PFO/ZnO nanocomposites. X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM) were used to determine the structural properties, while UV-Vis and photoluminescence (PL) were employed to investigate the optical properties of the films. XRD patterns confirmed that there was no variation in the structure of both PFO and ZnO NRs due to the blending process. FE-SEM micrographs displayed that ZnO NRs were well coated by PFO in all nanocomposite films. The absorption spectra of the nanocomposite thin films exhibited a red-shift indicating the increment in conjugation length of the PFO/ZnO nanocomposite. Significant quenching in the emission intensity of PFO was observed in fluorescence spectra of the nanocomposite films. This quenching was attributed to efficient charge transfer in the PFO/ZnO nanocomposites, which was further supported by the shorter PL lifetime of PFO/ZnO than that of the PFO thin film. The continuous decline in PL intensity of these nanocomposites is attributed to homogenous dynamic quenching between PFO and ZnO NRs.

Preparation and Optical Absorption Properties of CuO/SiO2 Nanocomposite Films Fabricated by Sol-Gel Technique

2009 ◽  
Vol 60-61 ◽  
pp. 283-287
Author(s):  
Jia Qin Liu ◽  
Yu Cheng Wu ◽  
Guang Hai Li ◽  
Li De Zhan
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Sol Gel ◽  
Dip Coating ◽  
Treatment Temperature ◽  
Nanocomposite Films ◽  
Sio2 Matrix ◽  
Heat Treated ◽  
Mesoporous Sio2 ◽  
Dip Coating Technique

CuO/SiO2 nanocomposite films were prepared by sol-gel process combined with the dip-coating technique. The mean diameter of CuO nanoparticles formed during the heat treatment process and mainly lay in the pores of mesoporous SiO2 matrix increased by increasing the heat treatment temperature. Consequently, compared with mesoporous SiO2 matrix, the pore volume and specific surface area of prepared samples descend. The diffraction peaks of Cu and CuO and the crystalline diffraction ring of CuO with body centered cubic structure can be clearly observed after heat-treated in air and H2 at 800 oC for 1h. By increasing the heat treatment temperature and concentration of CuO, a slightly red-shift could be observed.

scholarly journals Effect of Donor-Acceptor Concentration Ratios on Non-Radiative Energy Transfer in Zero-Dimensional Cs4PbBr6 Perovskite/MEH-PPV Nanocomposite Thin Films

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 444 ◽  
Author(s):  
Bandar Ali Al-Asbahi ◽  
Saif M. H. Qaid ◽  
Abdullah S. Aldwayyan
Keyword(s):  
Thin Films ◽  
Energy Transfer ◽  
Critical Concentration ◽  
Critical Distance ◽  
Radiative Energy ◽  
Glass Substrates ◽  
Solution Blending ◽  
Radiative Energy Transfer ◽  
Blending Method ◽  
Concentration Ratios

Composite materials with different concentration ratios of a hybrid of zero-dimensional (0-D) Cs4PbBr6 perovskite, which acts as a donor (D), and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), which acts as an acceptor (A), were successfully prepared via a solution blending method prior to being deposited onto glass substrates by a spin-coating technique. The influence of acceptor content on the structural, optical, and energy transfer properties of the donor was investigated. The perovskite nanocrystals formed thin films without any chemical interactions within a matrix of MEH-PPV in the blend. The possibility of dipole–dipole (non-radiative) energy transfer from the 0-D Cs4PbBr6 to the MEH-PPV was proven. The energy transfer parameters such as Ro (critical distance of the energy transfer), kapp (apparent quenching constant), ∅ D A (quantum yield of D in the presence of A), τ D A (lifetime of D in the presence of A), PDA (probability of energy transfer), η (efficiency of energy transfer), RDA (energy transfer radius), kET (energy transfer rate constant), TDR (total decay rate), Ao (critical concentration of A), and Aπ (conjugation length) were calculated based on the absorption and emission measurements.

Sol-gel growth of Ni doped CdS on glass substrates: effect of spin coating speed and dopant concentration

2020 ◽  
Vol 10 ◽  
Author(s):  
Atefeh Nazari Setayesh ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spin Coating ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Rotation Speed ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Glass Substrates

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.

Deposition time dependent study of structural and optical properties of PbS thin films grown by CBD method

2020 ◽  
Vol 13 ◽  
Author(s):  
Minakshi Chaudhary ◽  
Yogesh Hase ◽  
Ashwini Punde ◽  
Pratibha Shinde ◽  
Ashish Waghmare ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Deposition Time ◽  
Secondary Growth ◽  
Cost Effective ◽  
Xrd Analysis ◽  
Structural Morphology ◽  
Glass Substrates ◽  
Cbd Method

: Thin films of PbS were prepared onto glass substrates by using a simple and cost effective CBD method. Influence of deposition time on structural, morphology and optical properties have been investigated systematically. The XRD analysis revealed that PbS films are polycrystalline with preferred orientation in (200) direction. Enhancement in crystallinity and PbS crystallite size has been observed with increase in deposition time. Formation of single phase PbS thin films has been further confirmed by Raman spectroscopy. The surface morphology analysis revealed the formation of prismatic and pebble-like PbS particles and with increase in deposition time these PbS particles are separated from each other without secondary growth. The data obtained from the EDX spectra shows the formation of high-quality but slightly sulfur rich PbS thin films over the entire range of deposition time studied. All films show increase in absorption with increase in deposition time and a strong absorption in the visible and sub-band gap regime of NIR range of the spectrum with red shift in band edge. The optical band gap shows decreasing trend, as deposition time increases but it is higher than the band gap of bulk PbS.

Effect of gamma radiation on the structural, thermal and optical properties of PMMA/Sn0.75Fe0.25S2 nanocomposite

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali A. Alhazime ◽  
Nesreen T. El-Shamy ◽  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Thermal Stability ◽  
Optical Properties ◽  
Gamma Irradiation ◽  
Optical Band Gap ◽  
Color Variation ◽  
Nanocomposite Films ◽  
Color Changes ◽  
Gamma Irradiated ◽  
Intermolecular Crosslinking ◽  
Amorphous Part

AbstractNanocomposite films of polymethylmethacrylate PMMA with Sn0.75Fe0.25S2 nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Changes in PMMA/Sn0.75Fe0.25S2 nanocomposite (NCP) due to gamma irradiation have been measured. XRD results indicate that the gamma doses of 10–80 kGy cause intermolecular crosslinking that reduces the ordered portion in the NPs. Bonding between the NPs and the host PMMA was confirmed by FTIR. TGA results indicate an enhancement in thermal stability in the NCP films irradiated with doses 20–80 kGy. The optical band gap was reduced from 3.23 to 2.47 eV upon gamma irradiation up to 80 kGy due bonding between the NPs and PMMA which enhanced the amorphous part of the NPs. Finally, the color variation between the blank and irradiated films (ΔE) was determined. Color changes immensely when the PMMA/Sn0.75Fe0.25S2 NCP films are gamma irradiated. Values of ΔE were as much as 31.6 which is an acceptable match in commercial reproduction on printing presses.

scholarly journals Enhancing Graphene Retention and Electrical Conductivity of Plasma-Sprayed Alumina/Graphene Nanoplatelets Coating by Powder Heat Treatment

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 643
Author(s):  
Xiaoyu Wu ◽  
Shufeng Xie ◽  
Kangwei Xu ◽  
Lei Huang ◽  
Daling Wei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Structural Integrity ◽  
Ceramic Coatings ◽  
Treatment Temperature ◽  
Graphene Nanoplatelets ◽  
Structural Defects ◽  
Temperature Plasma ◽  
Heat Treated ◽  
Plasma Sprayed

Burning loss of graphene in the high-temperature plasma-spraying process is a critical issue, significantly limiting the remarkable performance improvement in graphene reinforced ceramic coatings. Here, we reported an effective approach to enhance the graphene retention, and thus improve the performance of plasma-sprayed alumina/graphene nanoplatelets (Al2O3/GNPs) coatings by heat treatment of agglomerated Al2O3/GNPs powders. The effect of powder heat treatment on the microstructure, GNPs retention, and electrical conductivity of Al2O3/GNPs coatings were systematically investigated. The results indicated that, with the increase in the powder heat treatment temperature, the plasma-sprayed Al2O3/GNPs coatings exhibited decreased porosity and improved adhesive strength. Thermogravimetric analysis and Raman spectra results indicated that increased GNPs retention from 12.9% to 28.4%, and further to 37.4%, as well as decreased structural defects, were obtained for the AG, AG850, and AG1280 coatings, respectively, which were fabricated by using AG powders without heat treatment, powders heat-treated at 850 °C, and powders heat-treated at 1280 °C. Moreover, the electrical conductivities of AG, AG850, and AG1280 coatings exhibited 3 orders, 4 orders, and 7 orders of magnitude higher than that of Al2O3 coating, respectively. Powder heat treatment is considered to increase the melting degree of agglomerated alumina particles, eventually leaving less thermal energy for GNPs to burn; thus, a high retention amount and structural integrity of GNPs and significantly enhanced electrical conductivity were achieved for the plasma-sprayed Al2O3/GNPs coatings.

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