Effects of solvent vapor pressure and spin-coating speed on morphology of thin polymer blend films

Kamanyi, Albert E.; Ngwa, Wilfred; Luo, Weili; Grill, Wolfgang

doi:10.1117/12.776274

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…In the other set (i.e., Sol), the CBP layer was made by spin coating in a glovebox with a dry nitrogen atmosphere utilizing CBP solutions with solvents of different boiling points; MC (40 °C), chloroform (61 °C), and toluene (111 °C). Because differences in solvent boiling points have different vapor pressure that lead to differences in film thicknesses, the CBP concentration in the solutions was adjusted in the various solutions so as to obtain a final film thickness of ∼30 nm in each case. Aside from the CBP layer, the other layers were fabricated via vacuum deposition.…”

Section: Resultsmentioning

confidence: 99%

Root Causes of the Limited Electroluminescence Stability of Organic Light-Emitting Devices Made by Solution-Coating

Cho

Aziz

2018

ACS Appl. Mater. Interfaces

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Although organic electroluminescent materials have long promised the prospect of making organic light emitting devices (OLEDs) via low-cost solution-coating techniques, the electroluminescence stability of devices made by such techniques continues to be rather limited making them unsuitable for commercialization. The root causes of the lower stability of OLEDs made by solution-coating versus the more conventional vacuum-deposition remain unknown. In this work, we investigate and compare between solution-coated and vacuum-deposited materials under prolonged excitation, using the archetypical host material 4,4'-bis( N-carbazolyl)-1,1'-biphenyl as a model OLED material. Results show that solution-coated films are more susceptible to degradation by excitons in comparison to their vacuum-deposited counterparts, resulting in a faster decrease in their luminescent quantum yield. The degradation rate also depends on the choice of solvent that was used in the solution-coating process. Results also show that the decrease in quantum yield is caused by exciton-induced chemical decomposition in the material as well as some possible molecular reorganization or aggregation, both of which are induced by excitons and proceed more quickly in case of solution-coated films. The faster degradation in the solution-coated films appears to originate primarily from their different morphological makeup and not due to chemical impurities. The findings uncover what appears to be one of the fundamental root causes of the lower stability of solution-coated OLEDs in general.

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Section: Resultsmentioning

confidence: 99%

Root Causes of the Limited Electroluminescence Stability of Organic Light-Emitting Devices Made by Solution-Coating

Cho

Aziz

2018

ACS Appl. Mater. Interfaces

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“…In addition, when using solvent casting methods, the choice of solvent may be important, as differences in vapor pressure of the solvent will result in different rates of vaporization speed and ultimately alter the morphology and characteristics of the resulting film (Kamanyi, Ngwa, Luo, & Grill, 2008). In addition, when using solvent casting methods, the choice of solvent may be important, as differences in vapor pressure of the solvent will result in different rates of vaporization speed and ultimately alter the morphology and characteristics of the resulting film (Kamanyi, Ngwa, Luo, & Grill, 2008).…”

Section: Spin-coatingmentioning

confidence: 99%

Surface modification of magnesium by functional polymer coatings for neural applications

Augello

Liu

2015

Surface Modification of Magnesium and Its Alloys for Biomedical Applications

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“…Moreover, the properties (such as the boiling point, vapor pressure, and evaporation rate) of the solvent implied in the fabrication of the mixed layers have a great impact on their morphology and roughness [ 37 ]. Thus, films deposited by spin-coating from blend solutions containing solvents with a high vapor pressure display an increased surface roughness because the evaporation occurs faster [ 38 ], whereas films deposited from slowly evaporating solvents feature a smooth surface [ 39 ].…”

Section: Introductionmentioning

confidence: 99%

Macrocyclic Compounds: Metal Oxide Particles Nanocomposite Thin Films Deposited by MAPLE

et al. 2023

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Nanocomposite films based on macrocyclic compounds (zinc phthalocyanine (ZnPc) and 5,10,15,20-tetra(4-pyridyl) 21H,23H-porphyrin (TPyP)) and metal oxide nanoparticles (ZnO or CuO) were deposited by matrix-assisted pulsed laser evaporation (MAPLE). 1,4-dioxane was used as a solvent in the preparation of MAPLE targets that favor the deposition of films with a low roughness, which is a key feature for their integration in structures for optoelectronic applications. The influence of the addition of ZnO nanoparticles (~20 nm in size) or CuO nanoparticles (~5 nm in size) in the ZnPc:TPyP mixture and the impact of the added metal oxide amount on the properties of the obtained composite films were evaluated in comparison to a reference layer based only on an organic blend. Thus, in the case of nanocomposite films, the vibrational fingerprints of both organic compounds were identified in the infrared spectra, their specific strong absorption bands were observed in the UV–Vis spectra, and a quenching of the TPyP emission band was visible in the photoluminescence spectra. The morphological analysis evidenced agglomerated particles on the composite film surface, but their presence has no significant impact on the roughness of the MAPLE deposited layers. The current density–voltage (J-V) characteristics of the structures based on the nanocomposite films deposited by MAPLE revealed the critical role played by the layer composition and component ratio, an improvement in the electrical parameters values being achieved only for the films with a certain type and optimum amount of metal oxide nanoparticles.

show abstract

Effects of solvent vapor pressure and spin-coating speed on morphology of thin polymer blend films

Cited by 4 publications

References 8 publications

Root Causes of the Limited Electroluminescence Stability of Organic Light-Emitting Devices Made by Solution-Coating

Root Causes of the Limited Electroluminescence Stability of Organic Light-Emitting Devices Made by Solution-Coating

Surface modification of magnesium by functional polymer coatings for neural applications

Macrocyclic Compounds: Metal Oxide Particles Nanocomposite Thin Films Deposited by MAPLE

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