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1

Light scattering by horizontally oriented square pyramid in the Wentzel–Kramers–Brillouin approximation

Tari El Mostafa, Bahaoui Abdelhadi, Lamsoudi Redouane, Khouilid Mohammed, Ibnchaikh Mohamed

Optica Applicata

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2022

|

Vol. 52, nr 2

213--228

EN

In this research, we studied the sensitivity of the form factor of a pyramidal ice crystal in the Wentzel–Kramers–Brillouin (WKB) approximation to its geometrical characteristics: the shape, spatial orientation, aspect ratio and size parameter. Using the WKB method, we derive an analytical formula of the form factor of horizontally oriented square pyramid. We will begin this work by applying the WKB approximation to the case of a particle which rotates about its main axis. Then, we will move to deal with the case of a particle which rotates about an axis perpendicular to its main axis in a future work. In addition, the coefficient of extinction is also given. To illustrate our analytical results, some numerical examples are analyzed.

2

Light waves scattering from an anisotropic semi-soft boundary medium with spectral dependence

Huang Zhiru, Dai Qihang, Ji Xiaoling, Wang Tao

Optica Applicata

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2021

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Vol. 51, nr 2

271--280

EN

The far-zone behavior of polychromatic light waves on scattering from an anisotrophic semi-soft boundary medium with spectral dependence was considered, and the spectral density and the spectral degree of coherence of the far-zone scattered field were investigated. It is shown that the distributions of the spectral density and the spectral degree of coherence of scattered field are closely related with the rms width, the center wavelength, and the maximum value of the center wavelength of the scattering potential of the scattering medium.

3

Determination of the complex refractive index of a subwavelength-diameter spider thread on silver coating by light scattering

Morita Aya, Tajima Fumiaki, Yuji Toshifumi, Mamat Sarizam, Mungkung Narong

Przegląd Elektrotechniczny

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2020

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R. 96, nr 9

138--142

EN

In this study, we have created nano-scale silver pipes by sputtering the silver material which frequently shows negative or less-than 1 refractive index onto the spider thread thinner than optical wavelength with. As a part of the study to investigate distribution of the complex refractive index which indicates optical and electromagnetic properties of the resulting silver pipes, we used light scattering method using linearly polarized laser with wavelength of 660 nm and radiated it perpendicularly to the silver pipe to measure the angular distribution of the scattered light intensity. Using the numerical calculation with Coaxial cylinder model based on the values found through preceding studies, we calculated the angular distribution of the scattered light intensity, and fitted the calculation result to the measurement result. This allowed us to determine the complex refractive index and outer diameter of the silver pipe along with the error range. The silver pipe was observed with field emission scanning electron microscope (FE-SEM) and the outer diameter of the silver pipe was estimated. This outer diameter was compared with the outer diameter obtained by fitting the calculation result with the light scattering method to the measurement result to evaluate the validity of the measurement result. This revealed that the result obtained with light scattering method has showed good agreement with that measured using FE-SEM.

PL

W artykule przedstawiono metodę badania nanorurek srebrnych wytwarzanych metodą rozpylania. Do badania właściwości rurek, przede wszystkim ich grubości wykorzystano pomiar światła rozproszonego na długości nici. Do pomiaru wykorzystano światło laserowe o o długości 660 nm. Opracowano model matematyczny metody pomiar współczynnika załamania światła. Dokładność metody potwierdzono wykorzystując mikroskop typu FE-SEM.

4

Convergence of Monte Carlo algorithm for solving integral equations in light scattering simulations

Kraszewski Maciej, Pluciński Jerzy

Optica Applicata

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2020

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Vol. 50, nr 1

17--35

EN

The light scattering process can be modeled mathematically using the Fredholm integral equation. This equation is usually solved after its discretization and transformation into the system of algebraic equations. Volume integral equations can be also solved without discretization using the Monte Carlo algorithm, but its application to the light scattering simulations has not been sufficiently studied. Here we present the implementation of this algorithm for one and three-dimensional light scattering computations and discuss its applicability in this field. We show that the Monte Carlo algorithm can provide valid and accurate results but, due to its convergence properties, it might be difficult to apply for problems with large volumes or refractive indices of scattering objects.

5

Application of the Monte Carlo algorithm for solving volume integral equation in light scattering simulations

Kraszewski Maciej, Pluciński Jerzy

Optica Applicata

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2020

|

Vol. 50, nr 1

1--15

EN

Various numerical methods were proposed for analysis of the light scattering phenomenon. An important group of these methods is based on solving the volume integral equation describing the light scattering process. The popular method from this group is the discrete dipole approximation. Discrete dipole approximation uses various numerical algorithms to solve the discretized integral equation. In the recent years, the application of the Monte Carlo algorithm as one of them was proposed. In this research, we analyze the application of the Monte Carlo algorithm for two cases: the light scattering by large particles and by random conglomerates of small particles. We show that if proper preconditioning of the numerical problem is applied, the Monte Carlo algorithm can solve the underlying systems of linear equations. We also show that the efficiency of the Monte Carlo algorithm can be increased by reusing performed computations for various incident electromagnetic waves and the applicability of the Monte Carlo algorithm depends on the particular use case. It is unlikely to be used in the case of light scattering by the large particles due to computational times inferior comparing with the other numerical methods but may become useful in the case of light scattering by the random conglomerates of small scattering particles.

6

Reciprocity relations for light wave scattered by a particulate collection

Jiang Z., Zhu Z., Wang T.

Optica Applicata

|

2018

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Vol. 48, nr 4

661--670

EN

Two Fourier relations of light waves scattered by a random-distributed particulate medium have been investigated. We find that the scattered field and the particulate collection satisfy two Fourier relations, i.e. the spectral density is directly proportional to a Fourier transform of a convolution of correlation coefficient of each particle and correlation coefficient of distribution function of the whole collection, and the spectral degree of coherence is directly proportional to a Fourier transform of a convolution of strength of the scattering potential of each particle and strength of the distribution function of the whole collection. To illustrate these relations, behaviors of the far-field generated by Gaussian-correlated particles with Gaussian-correlated distributions have been discussed.

7

Wykorzystanie zjawiska rozpraszania światła do oceny stanu powierzchni tnących ostrzy technicznych

Łukianowicz C., Kapłonek W., Radomska E.

Stal, Metale & Nowe Technologie

|

2017

|

nr 3-4

36--39

PL

W artykule przedstawiono możliwości wykorzystania zjawiska rozpraszania światła do szybkiej bezstykowej oceny stanu powierzchni tnących przemysłowych ostrzy technicznych. Pomysł opiera się na obserwacji i ocenie ilościowej rozkładu kątowego natężenia światła rozproszonego przez powierzchnie ostrza.

EN

The paper presents the possibilities of the use of the light scattering phenomenon for the rapid non-contact assessment of the surface condition of the cutting edges of industrial cutting blades. The idea is based on the observation and quantitative evaluation of the angular distribution of the intensity of light scattered by the surfaces of a cutting blade.

8

Metody rozpraszania światła w ocenie jakości środków smarowych

Woch J., Iłowska J., Dejnega B., Korasiak K., Gniady J.

Nafta-Gaz

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2017

|

R. 73, nr 10

784--792

PL

Metody analityczne wykorzystujące zjawisko rozpraszania światła (ang. light scattering, LS) są narzędziem do charakterystyki mikrostruktury układów koloidalnych i oceny ich stabilności w czasie, użytecznymi w ocenie jakości środków smarowych i eksploatacyjnych. Dynamiczne rozpraszanie światła (ang. dynamic light scattering, DLS) w sposób nieinwazyjny umożliwia pomiar wielkości cząstek w dyspersji. Parametry interakcji dynamicznego i statycznego rozpraszania światła (SLS) są pomocne przy szybkim określaniu i porównywaniu stabilności rozcieńczonych koloidów. Obserwacja zmian natężenia światła rozproszonego przez cząstki na różnych wysokościach próbki informuje o charakterze występującej utraty stabilności i umożliwia wcześniejsze wykrycie zmian niż metody klasyczne. W artykule przedstawiono metodyki wykorzystywane w ICSO wraz z przykładami ich zastosowania w praktyce do oceny jakości przemysłowych układów koloidalnych.

EN

Light scattering (LS) analytical methods are used to characterize the microstructure of colloidal systems and to evaluate their stability over time, useful in assessing the quality of lubricants and operating fluids. DLS (dynamic light scattering) is a non-invasive method for the determination of the size of the particles in dispersion. Interaction parameters for dynamic and static light scattering (SLS) are helpful in the rapid determination and comparison of the stability of diluted colloids. Observation of changes in light intensity scattered by particles at different heights of the sample indicates the nature of the resulting loss of stability and allows earlier detection of changes than classical methods. The paper presents methodologies for three LS methods applied in ICSO and the correlation of their results for practical application. The evaluation of the quality of various industrial lubricants is presented for formulations analyzed and developed in ICSO.

9

Calculation methods of interaction of electromagnetic waves with objects of complex geometries

Shopa M.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2016

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Vol. 20, No 2

231--240

EN

Modeling of the electromagnetic interaction with different homogeneous or inhomogeneous objects is a fundamental and important problem. It is relatively easy to solve Maxwell equations analytically when the scattering object is spherical or cylindrical, for example. However, when it loses these properties all that is left for us is to use approximation models, to acquire the solution we need. Modeling of complex, non-spherical, asymmetric particles is used to study cosmic, cometary dust, aerosols, atmospheric pollution etc. Few analytical, surface-based and volume-based methods of light scattering modeling, most commonly used by scientists, are reviewed here.

10

Właściwości i cechy geometryczne współwytłaczanych rur oświetleniowych

Sikora J. W., Żelazek K., Nowicki M.

Przetwórstwo Tworzyw

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2016

|

T. 22, Nr 3 (171)

132--141

PL

Za pomocą linii technologicznej do współwytłaczania otrzymano dwuwarstwowe rury o różnej grubości warstwy zewnętrznej i wewnętrznej, wykorzystywane w branży reklamy świetlnej. Celem takiej budowy wytłoczyny jest przede wszystkim zwiększenie odkształcalności, jak i uzyskanie odpowiedniego rozproszenia światła. Otrzymane rury poddano badaniom, określając ich wymiary poprzeczne - grubość poszczególnych warstw, wytrzymałość na zginanie i kąt ugięcia z wykorzystaniem aparatu Dynstat. Próbki wycięte z otrzymanych wytłoczyn poddano również badaniom pomiaru natężenia barwy przepuszczanego światła z użyciem spektrofotometru.

EN

Using a line for double-layer co-extrusion to give pipes of different thicknesses inner and outer layer, used in the field of illuminated advertising. The purpose of this design of the extrudate is mainly to increase the deformability and achieve proper dispersion of the light. The resulting pipe was tested, the dimensions of the cross - thickness of the individual layers, the bending strength and the deflection angle using a Dynstat device. Samples cut from the extrudate were subjected to the tests measuring the color intensity of the light transmitted by a spectrophotometer.

11

Estimation size of aerosol droplets produced by explosion

Śmigielski G., Dygdała R., Serejko G., Kaczorowski M.

Przegląd Elektrotechniczny

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2016

|

R. 92, nr 11

91--94

EN

This paper presents methodology of droplet diameter measurement with a recorder designed to catch droplets from an aerosol jet produced by explosion. A substantial part of the paper is devoted to the problem of determination of the scaling coefficient allowing to recalculate the diameters of droplet traces left on the recorder’s glass plate into the diameters of droplets while in the air. In this context the methodology of determination of diameters of droplets in laboratory using diffraction images of the laser light beam scattered on the aerosol droplets is discussed.

PL

W artykule przedstawiono metodologię pomiaru kropel aerozolu wodnego wytworzonego metodą wybuchową w zaprojektowanym rejestratorze. Znaczna część artykułu skupia się na określeniu współczynnika skali między kroplami schwytanymi przez rejestrator, a tymi będącymi w powietrzu tuż po wytworzeniu aerozolu. Określenie współczynnika skali wielkości kropel wykonano w laboratorium za pomocą lasera I analizy obrazów dyfrakcyjnych.

12

Optical diagnostics of a single evaporating droplet using fast parallel computing on graphics processing units

Jakubczyk D., Migacz S., Derkachov G., Woźniak M., Archer J., Kolwas K.

Opto-Electronics Review

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2016

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Vol. 24, No. 3

108--116

EN

We report on the first application of the graphics processing units (GPUs) accelerated computing technology to improve performance of numerical methods used for the optical characterization of evaporating microdroplets. Single microdroplets of various liquids with different volatility and molecular weight (glycerine, glycols, water, etc.), as well as mixtures of liquids and diverse suspensions evaporate inside the electrodynamic trap under the chosen temperature and composition of atmosphere. The series of scattering patterns recorded from the evaporating microdroplets are processed by fitting complete Mie theory predictions with gradientless lookup table method. We showed that computations on GPUs can be effectively applied to inverse scattering problems. In particular, our technique accelerated calculations of the Mie scattering theory on a single-core processor in a Matlab environment over 800 times and almost 100 times comparing to the corresponding code in C language. Additionally, we overcame problems of the time-consuming data post-processing when some of the parameters (particularly the refractive index) of an investigated liquid are uncertain. Our program allows us to track the parameters characterizing the evaporating droplet nearly simultaneously with the progress of evaporation.

13

Niestandardowe metody optyczne w badaniach powierzchni elektrochemicznie spasywowanego stopu Ti6Al7Nb

Wolska N., Jaglarz J, Szewczenko J

Ochrona przed Korozją

|

2016

|

nr 3

74--78

PL

Celem pracy jest przedstawienie możliwości zastosowania metod optycznych do wyznaczenia parametrów topograficznych powierzchni stopu Ti przed i po procesie pasywacji, jak również określenie wpływu wstępnych obróbek modyfikujących powierzchnie stopu na grubość tworzonych warstw pasywnych. Zastosowana w niniejszej pracy metodyka pomiarowa, wykorzystująca klasyczne i niestandardowe techniki badań optycznych, pozwoliła na wyznaczenie grubości warstw, chropowatość, długość autokorelacyjną i inne parametry statystyczne opisujące topografię powierzchni. Zaletą przedstawionych niestandardowych technik jest ich nie-inwazyjność i bezkontaktowość.

EN

The aim of this work is presentation of optical techniques applied for the measurements of topographic parameters of Ti alloy before and after its passivation, as well as determination of the influence of pre-treatment methods on the thickness of passive films. The applied methodology is non destructive and it includes standard and non-standard optical techniques to determine the thickness, roughness, autocorrelation length and other statistic parameters of film. Advantage of presented non-standard techniques is their non-destructive and non-invasive character.

14

Zadanie proste i odwrotne w skaterometrii nierówności powierzchni

Łukianowicz C.

Mechanik

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2016

|

R. 89, nr 11

1614--1615

PL

Przedstawiono dwa podstawowe problemy związane z zastosowaniem w pomiarach nierówności powierzchni zjawiska rozpraszania światła. Przybliżono ideę rozwiązania zadania odwrotnego w pomiarach wykorzystujących optyczne przekształcenie Fouriera

EN

Two major problems associated with the use phenomenon of light scattering for the measurement of surface roughness are outlined briefly. Idea solve the inverse problem in the measurements using optical Fourier transform is shown.

15

Przegląd metod skaterometrycznych stosowanych do aktywnej kontroli nierówności powierzchni

Łukianowicz Cz.

Mechanik

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2016

|

R. 89, nr 11

1670--1671

PL

W artykule dokonano przeglądu metod aktywnej kontroli nierówności powierzchni części maszyn wykorzystujących zjawisko rozpraszania światła. Dokonano krótkiej charakterystyki wybranych metod aktywnej kontroli chropowatości powierzchni.

EN

The in-process inspection of surface texture of machine elements by methods that use light scattering is analysed. A brief characterization of selected methods of in-process inspection of surface roughness was presented.

16

Ultrasonic-assisted synthesis of reactive carboxymethyl cellulose stabilized nano zero-valent iron and its application for removal of Cr6+ and Cu2+ ions

Ayob A., Santiagoo R., Amneera W. A., Ismail N., Abdullah A. Z.

Environment Protection Engineering

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2016

|

Vol. 42, nr 2

55--79

EN

Carboxymethyl cellulose (CMC) was used in the chemical reduction using sodium borohydride to yield dispersive nano zero-valent iron (nZVI) particles as reactive and stable adsorbents. CMC- -stabilized nZVI particles were characterized via UV-visible light spectroscopy, X-ray diffraction, dynamic light scattering, transmission electron microscopy, and specific surface area assisted using a probe ultrasonication dispersing tool at 50% amplitude power. High catalytic reactivity obtained in pseudo-first order reaction for Cr6+ (rate constant K1 = 0.0311 min–1) and pseudo-second order for Cu2+ (rate constant K2 = 0.0946 g·mg–1·min–1) indicated that colloidal stability of nZVI particles can be achieved with a stabilizer for the removal of toxic contaminants.

17

Using the DDA (Discrete Dipole Approximation) Method in Determining the Extinction Cross Section of Black Carbon

Skorupski K.

Metrology and Measurement Systems

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2015

|

Vol. 22, nr 1

153--164

EN

BC (Black Carbon), which can be found in the atmosphere, is characterized by a large value of the imaginary part of the complex refractive index and, therefore, might have an impact on the global warming effect. To study the interaction of BC with light often computer simulations are used. One of the methods, which are capable of performing light scattering simulations by any shape, is DDA (Discrete Dipole Approximation). In this work its accuracy was estimated in respect to BC structures using the latest stable version of the ADDA (vr. 1.2) algorithm. As the reference algorithm the GMM (Generalized Multiparticle Mie-Solution) code was used. The study shows that the number of volume elements (dipoles) is the main parameter that defines the quality of results. However, they can be improved by a proper polarizability expression. The most accurate, and least time consuming, simulations were observed for IGT_SO. When an aggregate consists of particles composed of ca. 750 volume elements (dipoles), the averaged relative extinction error should not exceed ca. 4.5%.

18

Analiza rozpraszania światła na powierzchniach jednowarstwowych ściernych materiałów nasypowych z ziarnami ściernymi typu Trizact ™

Kapłonek W., Nadolny K., Baran J.

Mechanik

|

2015

|

R. 88, nr 8-9CD1

185--189

PL

W pracy przedstawiono zastosowanie metody rozpraszania światła do oceny stanu czynnej powierzchni jednowarstwowych ściernych materiałów nasypowych z ziarnami typu Trizact™. Analizie poddano siedem dysków ściernych o ziarnistości A160, A100, A65, A45, A30, A16, A6, które oświetlano wiązką laserową o długości fali λ = 660 nm. Światło odbite i rozproszone przez elementy powierzchni tworzyło obraz optyczny widoczny w płaszczyźnie obserwacji. Do analizy zastosowano oprogramowanie Image Pro®-Plus, w którym, dla zarejestrowanych obrazów, wyznaczano wybrane parametry geo i fotometryczne.

EN

The condition of surface of the abrasive tools is an important factor, which guaranteed the proper course and results of the machining process. Detection of fracture and abrasive wear of the grains as well as localization and analysis of smears of the work piece material can be assessed by the use of non-contact optical methods. In the work, the use of light scattering methods for assessment of condition of active surface of the monolayer abrasive grains Trizact™ was presented. Analysis were conducted on seven 7 Trizact™ abrasive discs with different gradations of agglomerate: A160, A100, A65, A45, A30, A16, A6, which were illuminated by a laser beam (wavelength λ = 660 nm). The light reflected and scattered by the surface elements has formed a characteristic pattern visible in a observation plan. For analysis of acquired images and determining selected geo- and photometric parameters was used the Image Pro® Plus software. The obtained results were compared with the analyses carried out for abrasive sheets with: Cubitron™ II grains, silicon carbide SiC grains as well as Al2O3 grains with sputtered layer of gold by PVD method.

19

Zastosowanie hybrydowego systemu pomiarowego wykorzystującego obrazowanie i analizę światła rozproszonego do oceny stanu powierzchni szlifowanych

Kapłonek W., Sutowski P., Nadolny K.

Inżynieria Maszyn

|

2015

|

R. 20, z. 1

89--103

PL

Jednym z niezwykle ważnych zagadnień we współczesnym przemyśle wytwórczym jest zapewnienie odpowiedniej oceny stanu powierzchni przedmiotów obrobionych. Ocena taka, z wielu względów, musi być realizowana w sposób bezstykowy, w stosunkowo krótkim czasie, nawet podczas ruchu badanej powierzchni względem czujnika pomiarowego. Takie wymagania skłaniają do stosowania tzw. systemów hybrydowych, łączących optyczne metody pomiarowe z technikami przetwarzania i analizy obrazu cyfrowego. W pracy przedstawiono jeden z takich systemów opracowany na Politechnice Koszalińskiej. Podano szczegółowy opis jego konstrukcji i konfiguracji oraz przedstawiono wybrane rezultaty uzyskane podczas prowadzonych badań eksperymentalnych, w których oceniano szlifowane powierzchnie próbek płaskich i walcowych o wysokościach nierówności w zakresie od 0,07 do 3,7 μm (parametr Ra) oraz od 0,8 do 25 μm (parametr Rz). Pozytywne rezultaty badań skłaniają do kontynuowania prac zarówno nad modyfikacją konstrukcji systemu, jak i nad określeniem zakresu jego dalszych zastosowań.

EN

One of the very important issues in the modern manufacturing industry is to ensure adequate assessment of the workpieces surfaces. Such an assessment, for many reasons, must be carried out in a non-contact way in a relatively short time, even while the examined surface is in movement. These requirements can be fulfilled by application of hybrid systems that combine optical measurement methods with techniques of digital image processing and analysis. In the work, one of such a hybrid systems developed in the Koszalin University of Technology has been presented. A brief description of its construction and configuration were given in Section 2. The selected results obtained in a frame of experimental investigations carried out during assessment of ground surfaces of flat and cylindrical samples were presented and discussed in Section 3. They were characterized by a surface roughness in a range from 0.07 to 3.7 μm (Ra parameter) as well as from 0.8 to 25 μm (Rz parameter). Positive results of investigations give a chance to continue the work, which will be focused on modification of the system construction as well as on searching for the areas of its further applications.

20

Improved Light Conversion Efficiency Of Dye-Sensitized Solar Cell By Dispersing Submicron-Sized Granules Into The Nano-Sized TiO2 Layer

Song S. A., Lim M. J., Jung K. Y., So W.-W., Moon S.-J.

Archives of Metallurgy and Materials

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2015

|

Vol. 60, iss. 2B

1467--1471

EN

In this work, TiO2 nanoparticles and submicron-sized granules were synthesized by a hydrothermal method and spray pyrolysis, respectively. Submicron-sized granules were dispersed into the nano-sized TiO2 layer to improve the light conversion efficiency. Granules showed better light scattering, but lower in terms of the dye-loading quantity and recombination resistance compared with nanoparticles. Consequently, the nano-sized TiO2 layer had higher cell efficiency than the granulized TiO2 layer. When dispersed granules into the nanoparticle layer, the light scattering was enhanced without the loss of dye-loading quantities. The dispersion of granulized TiO2 led to increase the cell efficiency up to 6.51%, which was about 5.2 % higher than that of the electrode consisting of only TiO2 nanoparticles. Finally, the optimal hydrothermal temperature and dispersing quantity of granules were found to be 200°C and 20 wt%, respectively.