Effect of flow dynamics on the growth kinetics of CdS thin films in chemical bath deposition

Erkan, Mehmet Eray; Jin, Michael H.‐C.

doi:10.1016/j.matchemphys.2012.01.093

Cited by 9 publications

(3 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was because the viscosity and density (see Table S4) of the solution decreased with the increase in temperature. With the increase of stirring speed, the Reynolds number increases and the thickness of the diffusion boundary layer (δ) decreases (see Table S5), which means that the diffusion length of dissolved APIs to the seed is reduced, thus increasing the deposition rate . As shown in Figure b, the crystal growth rate of allopurinol at 300 rpm was markedly higher than that at 100 rpm.…”

Section: Resultsmentioning

confidence: 98%

“…With the increase of stirring speed, the Reynolds number increases and the thickness of the diffusion boundary layer (δ) decreases (see Table S5), which means that the diffusion length of dissolved APIs to the seed is reduced, thus increasing the deposition rate. 45 As shown in Figure 4b, the crystal growth rate of allopurinol at 300 rpm was markedly higher than that at 100 rpm. However, as presented in Figure 4a, the stirring speed has only a small influence on the crystal growth kinetics of mesalazine and the crystal growth rate of mesalazine at 300 rpm was slightly higher than that at 100 rpm.…”

Section: Experimental Strategymentioning

confidence: 84%

See 1 more Smart Citation

Influence Mechanism of Polymeric Excipients on Drug Crystallization: Experimental Investigation and Chemical Potential Gradient Model Analysis and Prediction

Qiao

Weng

Sadowski

et al. 2023

Crystal Growth & Design

View full text Add to dashboard Cite

In this work, the influence of temperature, stirring speed, and polymeric excipients on crystal growth kinetics of active pharmaceutical ingredients (APIs) mesalazine and allopurinol was systematically investigated through experimental measurement and chemical potential gradient model. The results indicated that the two-step chemical potential gradient model showed good performance in modeling API crystal growth kinetics within the average relative deviations (ARDs) of 5%. Excipients (poly(ethylene glycol) (PEG), hydroxypropyl methyl cellulose (HPMC), and poly(vinyl pyrrolidone) (PVP)) played a crucial role in inhibiting the API crystal growth in all of the investigated systems. On one hand, excipients improved the API solubility, and on the other hand, the crystal growth rate of APIs was reduced remarkably by excipients. By comparing the diffusion rate constant (k d ) and the surface reaction rate constant (k s ) within the two-step chemical potential gradient model, it was found that the controlling step of mesalazine and allopurinol crystal growth was the surface reaction. Because of the presence of excipients, the diffusion rate constant was markedly decreased and the surface reaction order increased. Excipients hinder the surface reaction and decrease the crystal growth rate. Meanwhile, the crystal growth kinetics of mesalazine and allopurinol were predicted successfully with the ARDs of 2.5 and 6.5% under a certain temperature and stirring speed by the two-step chemical potential gradient model. This work provided a mechanistic understanding of how polymers inhibit API crystal growth.

show abstract

Section: Resultsmentioning

confidence: 98%

Section: Experimental Strategymentioning

confidence: 84%

Influence Mechanism of Polymeric Excipients on Drug Crystallization: Experimental Investigation and Chemical Potential Gradient Model Analysis and Prediction

Qiao

Weng

Sadowski

et al. 2023

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…However, several authors have reported explicitly or implicitly that the lower the reaction temperature the lower the thin film growth rate [12,15,20,21,23,28,34,35,54,[77][78][79][80][81]84,87,90,[103][104][105][106][107][108][109][110][111][112][113][114][115][116][117][118][119][120][121]. Thus, without delving into the cases in which homogeneous precipitation is favored, which limits the maximum d-a limit which was directly reported [12,15,21] or simply evident in the results reported [115,118,120] by some authors-the use of low temperatures lengthens the time required to achieve a thin film with determined d compared to the time required at higher temperatures.…”

Section: Selection Of a Convenient Temperaturementioning

confidence: 99%

Detailed Analysis of Five Aspects Addressed to Minimize Costs and Waste in the Chemical Bath Deposition of CdS Films Using the CdB–AC6H5O7–AOH–(NH2)2CS System

García-Valenzuela¹,

Castelo-González²,

Baez-Gaxiola³

et al. 2013

MSA

View full text Add to dashboard Cite

Five studies were conducted in order to produce less waste and economize the application of a CdCl 2 -Na 3 C 6 H 5 O 7 -KOH-H 3 BO 3 /NaOH/KCl-(NH 2 ) 2 CS definite aqueous system in the chemical bath deposition of CdS thin films, as well as to generate supporting information helpful to explain the effects of varying certain parameters established for the use of this formulation. These studies are related to the utility of the pH 10 borate buffer, to the selection of the appropriate OH -concentration, commercial alkali, and reaction temperature, and to the reusing of the residual solution. These studies were conducted by means of optical characterization, pH measurements, energy consumption tests, and chemical analysis; and all possible implications were analyzed in detail and widely supported by the literature. It is observed that the addition of 5.0 mL of pH 10 borate buffer in the reaction solutions only causes a slight reduction in the pH value and, therefore, in the thickness of the resulted films. It is observed that a decrease in CdCl 2 concentration causes an increase in the pH values, and when such reagent concentration is varied it is necessary to determine the pH value at which the best CdS films can be obtained; this indicates the existence of an optimum pH of deposition, depending on the used reagent concentrations. It is demonstrated that the use of KOH and NaOH is interchangeable, and the advantages of NaOH are evaluated in the context of hygroscopicity, CO 2 absorption, purity, and price. It is observed that the energy consumption when depositing a determined film is lower at high temperatures, and it is concluded that the time and energy savings at high temperatures are undoubtedly advantages in the deposition process of CdS thin films. A formulation to recycle the residual solution is presented, which is very important for the reducing of residual volume, and, therefore, in the minimizing of the environmental impact. An indirect objective of this work is to generate interest in identifying those points that could be modified in other chemical formulations to minimize costs and waste.

show abstract

Quantum confinement effects in Gd-doped CdS nanoparticles prepared by chemical precipitation technique

Thambidurai

Muthukumarasamy²,

Velauthapillai

et al. 2013

J Mater Sci: Mater Electron

View full text Add to dashboard Cite

Effect of flow dynamics on the growth kinetics of CdS thin films in chemical bath deposition

Cited by 9 publications

References 11 publications

Influence Mechanism of Polymeric Excipients on Drug Crystallization: Experimental Investigation and Chemical Potential Gradient Model Analysis and Prediction

Influence Mechanism of Polymeric Excipients on Drug Crystallization: Experimental Investigation and Chemical Potential Gradient Model Analysis and Prediction

Detailed Analysis of Five Aspects Addressed to Minimize Costs and Waste in the Chemical Bath Deposition of CdS Films Using the Cd<i>B</i>–<i>A</i>C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>–<i>A</i>OH–(NH<sub>2</sub>)<sub>2</sub>CS System

Quantum confinement effects in Gd-doped CdS nanoparticles prepared by chemical precipitation technique

Contact Info

Product

Resources

About