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"ABSTRAKMolekul DNA, sebagai devais elektronik molekular memiliki sifat yang sangat sensitif terhadap lingkungan baik itu lingkungan eksternal maupun internal. DNA dapat berada dalam kondisi tidak seimbang dan itu akan berpengaruh pada proses transpor muatan di DNA. Molekul DNA dapat berifat sebagai konduktor, semikonduktor atau isolator yang kemungkinan disebabkan dari lingkungannya. Oleh karena itu, pada studi ini penulis akan mempelajari pengaruh medan magnet dan konstanta hopping di pasangan Watson-Crick terhadap sifat transpor muatan di DNA Poly dA -Poly dT . Hamiltonian tight binding dan teori semi empirik Slater-Koster digunakan dalam memodelkan molekul. Dalam studi ini, semua jalur loncatan elektron dimungkinkan terjadi termasuk jalur loncatan antar-backbone. Transpor muatan di molekul DNA dipelajari dari menghitung density of state DOS , panjang lokalisasi, probabilitas transmisi, dan karaktristik I-V. DOS dihitung dengan menggunakan fungsi Green yang mempertimbangkan elektoda di kedua ujung molekul DNA. Panjang lokalisasi dihitung menggunakan metode transfer matriks dan ortonormalisasi Gram-Schmidt. Probabilitas transmisi dihitung menggunakan metode transfer matriks dan matriks hamburan, kemudian hasilnya digunakan untuk menghitung karakteristik I-V dengan menggunakan formula Landuer-Buttiker. Pengaruh medan magnet pada transpor muatan di molekul DNA dapat dilihat dari perubahan nilai panjang lokalisasi dan DOS elektron di DNA dengan perubahan nilai medan magnet. Konstanta hopping di pasangan Watson-Crick tidak memberikan pengaruh secara signifikan terhadap transpor muatan di molekul DNA. Hal ini ditandai dengan tidak banyaknya perubahan yang terjadi pada probabilitas transmisi dan karakteristik I-V ketika nilai konstanta hopping divariasikan.

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ABSTRAKDNA molekul, an element of molecular electronic device is very sensitive to the environment both external and internal environment. DNA may be in unequilibrium condition and it will affect charge transport process in DNA. DNA molecule can behave as a conductor, semiconductor or insulator which is maybe caused by the environment. Therefore, in this study we will study the effect of magnetic field and hopping constant on the Watson Crick pairs in the charge transport of DNA poly dA poly dT . Tight binding Hamiltonian and the empirical Slater Koster theory are used in modeling the molecule. In this study, all electron hopping paths are considered, including backbone backbone hopping paths. Charge transport DNA is studied by calculating density of state DOS , localization length, transmission probability, and I V characteristic. DOS is calculated using Green function by considering the electodes at both ends of the DNA molecule. The localization length is calculated using the matrix transfer method along with Gram Schmidt orthonormalization. The transmission probability is calculated using matrix transfer and scattering matrix method, then it is used in calculating the I V characteristic by using Landuer Buttiker formula. The effect of the magnetic field on charges transport in DNA molecule can be seen from the decreasing and increasing of the value of localization length and electron rsquo s DOS in DNA as magnetic field is varied. Hopping constant on the Watson Crick pairs does not have a significant effect on the charge transport DNA molecule. This characteristic is indicated by the lack of changes in the transmission probability and the I V characteristic when the value of the hopping constants is varied."

"Sifat transportasi elektron di molekul DNA poly dA -poly dT telah dipelajari. Kami menggunakan dua model DNA yang berbeda, yang direpresentasikan secara matematis dengan model ikatan kuat Hamiltonian dan teori Slater-Koster. Panjang molekul DNA yang digunakan 32 pasangan basa. Kedua ujung rantai molekul dikoneksikan dengan elektroda. Sifat transportasi elektron dipelajari dari probabilitas transmisi dan karakteristik I-V. Probabilitas transmisi dihitung dengan metode transfer matriks dan matriks hamburan. Formula Landauer Buttiker digunakan untuk menghitung karakteristik I-V. Selanjutnya, sifat transportasi elektron dibandingkan di variasi temperatur, frekuensi getar gerak memutar dan energi gangguan lingkungan luar. Hasilnya menunjukan bahwa pada kedua model mengalami peningkatan probabilitas transmisi elektron dan arus seiring meningkatnya frekuensi getar gerak memutar rantai DNA. Namun saat temperatur ditingkatkan, probabilitas transmisi dan arusnya menurun dan tegangan ambang membesar di tiap variasi frekuensi getar. Kemudian ketika energi gangguan luar meningkat, probabilitas transmisi dan arus semakin kecil, demikian pula tegangan ambangnya. Nilai puncak-puncak probabilitas transmisi di model B lebih besar dari model A, namun kurva I-V model B dapat lebih besar atau lebih kecil. Peningkatan maupun penurunan transmisi dan arus di model A lebih besar ketika tidak ada gangguan backbone, tendensi terbalik ketika terdapat energi gangguan backbone.

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The properties of electron transport in poly dA poly dT DNA molecules have been studied. We use two models of DNA which are represented mathematically by tight binding Hamiltonian model and Slater Koster theory. DNA molecules which are used have 32 base pairs long. Each end of DNA chain are connected to metallic electrodes. The properties of electron, are studied from transmission probability and I V characteristic curves. The transmission probabilities are calculated using transfer matrix and scattering matrix methods. The Landauer Buttiker formula is used in computing I V characteristics. The properties of transport electron are compared in variation of temperatures, frequencies of twisting motion and disorder energy due to environment. The results show that the transmission probability and current values increase as frequency of twisting motion increases in both of models. However, as temperature become higher, the transmission probability and current values decrease, but the treshold voltages increase for all frequency variations. Then, as disorder energy becomes higher, the transmission probability and current values decrease, and the threshold voltages decrease, too. Transmission probability values of model B are higher than model A, but the I V curve of model B can be higher and lower. Both of the enhancement or reduction of transmission and current in model A is higher for without backbone disorder energy condition, but the tendency reversed when in backbone disorder energy condition."

"Penelitian teori ini bertujuan untuk menginvestigasi pengaruh medan listrik dan medan magnet terhadap transpor elektron pada molekul DNA poli(dA)-poli(dT). Mekanisme transpor elektron dimodelkan menggunakan pendekatan hamiltonian ikatan kuat dengan melibatkan pengaruh temperatur dan frekuensi gerak memutar. Arus listrik yang melalui DNA dihitung menggunakan formula Landauer-Buttiker dengan perhitungan probabilitas transmisi menggunakan pendekatan fungsi green. Kemudian, faktor eksternal medan listrik dilibatkan mengikuti model Miller-Abraham. Sedangkan faktor eksternal medan magnet, dimodelkan menggunakan model Pierls. Hasil yang diperoleh menunjukan bahwa pengaruh medan listrik berdampak pada pelemahan probabilitas transmisi. Sebaliknya, pengaruh medan magnet memiliki dampak pada peningkatan arus listrik maksimum. Kemudian secara keseluruhan, frekuensi gerak memutar menyebabkan peningkatan pada probabilitas transmisi.

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This theoretical study aims to investigate the electric field and magnetic field influence on electron transport through DNA poly(dA)-poly(dT). The electron transport mechanism is modeled by the tight-binding Hamiltonian approach involving temperature and twisting motion frequency. The accumulation of electron current flowing through DNA is calculated using Landauer-Buttiker Formula from transmission probability obtained using green function. Then, the external disturbance, electric field, is considered using the Miller-Abraham model. On the other sides, the magnetic field effect is modeled by Pierls model. The results show that the electric field causes decrement on transmission probability. In contrast, magnetic field increases transmission probability. In contrast, the magnetic field increases the current. Furthermore, twisting motion frequency causes higher transmission probability."

"ABSTRAKKami mempelajari sifat transport muatan menggunakan molekul DNA aperiodik dan molekul DNA G4. Molekul DNA aperiodik mempelajari pengaruh nilai loncatan inter-strand pada karakteristik I-V. Molekul DNA G4 mempelajari pengaruh medan listrik dan medan magnet pada panjang lokalisasi, density of state DOS , dan karakteristik I-V. Sifat transport muatan dipelajari dengan menghitung probabilitas transmisi, karakteristik I-V, dan memberikan pengaruh medan listrik dan medan magnet. Pada molekul DNA aperiodik, dipelajari pengaruh nilai hopping inter-strand terhadap probabilitas transmisi dan karakteristik I-V. Probabilitas transmisi dihitung dengan metode transfer matriks, sedangkan karakteristik I-V dihitung dengan formula Launder-Buttiker. Pada molekul DNA G4, dipelajari pengaruh medan listrik dan medan magnet terhadap panjang lokalisasi, density of state DOS, dan karakteristik I-V. Panjang lokalisasi dihitung menggunakan metode transfer matriks, dan density of state DOS serta karakteristik I-V dihitung dengan metode fungsi Green.

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ABSTRACTThe charge transport of aperiodic DNA and G4 DNA molecule have been studied. On the aperiodic DNA molecule, the effect of the inter-strand hopping value on the I-V characteristic has been studied. The effect of the electric and magnetic field on the localization length, density of state (DOS), and I-V characteristics were studied G4 DNA molecule. Charge transport was studied by calculating the transmission probability, the I-V characteristic, by considering the effect of the electric and the magnetic field. In the aperiodic DNA molecule, we study the effect of hopping inter-strand on transmission probability and I-V characteristics. The transmission probability was calculated by the matrix transfer method, while the I-V characteristic was calculated by the Launder-Buttiker formula. In G4 DNA molecule, we studied the effect of the electric and magnetic field on the localization length, density of state (DOS), and I-V characteristic. Localization length was calculated using matrix transfer method, and density of state (DOS) and I-V characteristic was calculated by Green function method."

"ABSTRAKBanyak faktor yang dapat mengubah struktur energi DNA, dan pada akhirnya, hal tersebut berpengaruh kepada transpor elektron pada molekul DNA. Studi yang dilakukan berfokus kepada pengaruh medan listrik pada properti transpor muatan dari molekul DNA poly(dA)-poly(dT). Model DNA pada studi ini memperbolehkan elektron untuk mengalir dari backbone ke backbone. Model hamiltonian tight-binding digunakan dengan melibatkan medan listrik dan temperatur. Medan listrik diatur sejajar dengan sumbu heliks DNA. Medan listrik dimodelkan dengan mengacu pada formula Miller-Abraham yang mengubah konstanta hopping antar-sites dalam DNA. Metode transfer-matrix dan ortonormalisasi Gram-Schmidt digunakan untuk menghitung panjang lokalisasi. Retarded Green Function digunakan untuk menghitung DOS. Hasil yang didapatkan menunjukkan bahwa ketika medan listrik meningkat, terjadi pelebaran celah pada panjang lokalisasi dan DOS. Sedangkan peningkatan suhu meningkatkan disorder pada sistem.

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ABSTRACTThere are many factors that can change the energy structure of DNA, and in the end it can affects electronic transport in DNA molecules. The study will focus on the influence of the electric field on the charge transport properties of the poly(dA)-poly (dT) DNA molecule. The DNA model in this study allows electrons to propagate from the backbone to backbone. The tight-binding Hamiltonian model is used by taking into account the electric field and temperature influence. The electric field is applied parallel to the helical axis of DNA. The electric field which change the hopping constant between sites in DNA will be modeled by using  the Miller-Abraham formula. The transfer-matrix method and Gram-Schmidt orthonormalisation method are used to calculate the length of localization. Retarded Green Function is used to calculate DOS. The results obtained show that when electric field increases, there will be widening of the gap at the localization length and DOS. While the increase in temperature will increase disorder in the system."

"Sifat transpor muatan pada molekul DNA untai ganda dan DNA G4 telah dipelajari. Kami menggunakan dua model DNA yang direpresentasikan secara matematis dengan menggunakan model Hamiltonian tight binding. Model yang pertama adalah DNA untai ganda dengan panjang 32 pasangan basa yang disusun secara random. Transpor muatan untuk molekul DNA ini dipelajari dari probabilitas transmisi dan karakteristik I-V dengan memvariasikan hopping elektron inter-strand tegak lurus. Peningkatan hopping electron inter-strand tegak lurus menyebabkan probabilitas transmisi dan arus meningkat, tetapi saat temperaturnya dinaikkan probabilitas transmisi dan arus menurun. Model kedua adalah DNA G4, Sifat transpor muatan pada molekul ini dipelajari dari panjang lokalisasi dengan panjang 102 pasangan basa, density of states dan karakteristik I-V masing-masing dengan 32 tumpukan tetrad guanin, yang diberi pengaruh medan listrik dan temperatur, Probabilitas transmisi dan panjang lokalisasi dihitung menggunakan metode transfer matriks. Formula landauer Buttiker digunakan untuk menghitung karakteristik I-V. Metode fungsi green untuk menghitung probabilitas transmisi dan density of states. Hasil perhitungan medan listrik dan temperatur terhadap sifat transpor muatan yaitu menurunkan panjang lokalisasi, density of states, dan arus, saat meningkatnya medan listrik dan temperatur.

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The charge transport property on double-stranded DNA and G4 DNA molecules has been studied. We use two DNA models that are mathematically represented using Hamiltonian tight binding models. The first model is double stranded DNA with length of 32 base pairs arranged randomly. The charge transport for this DNA molecule is studied from transmission probabilities and I-V characteristics by varying of electron hopping in perpendicular inter-strand. Increased of electron hopping in perpendicular inter-strand causes the transmission and current probabilities to increase, but when temperature is increased the transmission probabilities and current is decrease. The second model is DNA G4. The charge transport property in this molecule is studied from localization length with length of 102 base pairs, density of states and I-V characteristics with 32 stacks of guanine tetrads respectively that influenced of electric field and temperature. Transmission probability and localization length are calculated using matrix transfer method. The buttiker landauer formula is used to calculate the I-V characteristics. Green function method for calculating transmission probability and density of states. The result of electric field and temperature calculation on charge transport leads to decreasing localization length, density of states, and current, when increasing of electric field and temperature."

"Pendekatan Hamiltonian tight binding digunakan untuk mempelajari sifat transport muatan di molekul DNA. Sifat transport muatan ini dipelajari dengan menggunakan dua model DNA yaitu model DNA Aperiodik dan model DNA G4. Model DNA Aperiodik terdiri dari 32 pasangan basa ATGC yang tersusun secara acak dengan sequence GCTAGTACGTGACGTAGCTAGGATATGCCTGA. Pada model ini dilakukan perhitungan menggunakan metode transfer matriks dan metode hamburan untuk mendapatkan probabilitas transmisi serta menghitung karakteristik I-V berdasarkan formula Landauer Büttiker dengan memvariasikan nilai kopling 𝛼 interstrand. Peningkatan nilai kopling 𝛼 interstrand memberikan dampak yang sangat baik terhadap transport muatan yaitu terjadinya peningkatan probabilitas transmisi dan karakteristik IV pada tegangan tinggi. Sedangkan, model DNA G4 terdiri dari 4 basa guanine yang tersusun membentuk struktur planar, g-quartet yang disusun secara bertumpuk. Pada model DNA ini dilakukan perhitungan panjang lokalisasi menggunakan metode transfer matriks dan perhitungan density of state (DOS) dan karakteristik I-V menggunakan pendekatan fungsi green di bawah pengaruh temperatur dan medan magnet. Temperatur menyebabkan terjadinya fluktuasi termal yang menurunkan panjang lokalisasi, density of state (DOS) dan karakteristik I-V di molekul DNA G4. Sedangkan, medan magnet menyebabkan terjadinya pergeseran fase keadaan elektron di jalur transport yang mempengaruhi panjang lokalisasi dan DOS yang berimbas pada peningkatan arus hingga di tegangan tinggi.

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The tight binding Hamiltonian approach is used in studying charge transport properties DNA molecules. The charge transport properties are studied by using two DNA models, the Aperiodic DNA molecule and the G4 DNA molecule. The Aperiodic DNA model consist of 32 base pairs that ATGC arranged randomly with sequence GCTAGTACGTGACGT-AGCTAGGATATGCCTGA. In this model, transfer matrix method and scattering method are used in obtain transmission probability and calculating the I-V characteristic for various values of interstrand coupling α. The increase of α gives a very good impact on charge transport that is the increase of transmission probability and I-V characteristic at high voltages. G4 DNA model consists of planar structure of four guanine bases, g-quartet, which are stacked on top each other. In this DNA model, localization length is calculated using transfer matrix method and the density of state (DOS) as well as I-V characteristic are calculated using green function approach under the influence of temperature and magnetic field. The temperature causes thermal fluctuations that decreases the localization length, density of state (DOS) and I-V characteristics in G4 DNA molecule. Meanwhile, magnetic field causes a shift in electron wave phase along its travel path which is affecting the localization length and DOS which lead to current increament up to high voltage."

"This book about charge transport in organic semiconductors, frontiers of organic conductors and superconductors, fullerenes, carbon nanotubes, and graphene for molecular electronics, current challenges in organic photovoltaic solar energy conversion, molecular monolayers as semiconducting channels in field effect transistors, issues and challenges in vapor-deposited top metal contacts for molecule-based electronic devices, and spin polarized electron tunneling and magnetoresistance in molecular junctions."

"This book about molecular electronic junction transport : some pathways and some ideas, unimolecular electronic devices, active and non-active large-area metal–molecules–metal junctions, charge transport in single molecular junctions at the solid/liquid interface, and tunneling spectroscopy of organic monolayers and single molecules, molecule logical devices."

"Pengembangan Light Emitting Diode (LED) mengarah pada power dan efisiensi yang lebih tinggi. Pada beberapa tahun terakhir, muncul pula Organic Light Emitting Diodes (OLED) yaitu LED yang terbuat dari material organik. Jika dibandingkan dengan LED, OLED memiliki beberapa kelebihan, misalnya display elektroluminansinya lebih luas, mempunyai emisi yang berwarna-warni, efisiensi luminansi yang lebih tinggi, dan molekul organik yang ada tidak terbatas jumlahnya.Ketidakstabilan mekanis material organik menyebabkan munculnya beberapa kekurangan OLED, salah satu contohnya adalah temperatur transisi glass molekul pada OLED yang rendah. Ketidakstabilan juga merupakan faktor penyebab menurunnya tingkat life time bahan. Di samping itu, mobilitas material organik yang rendah membatasi kinerja maksimum OLED.Pada riset ini dipelajari teori dasar yang diperlukan untuk membandingkan OLED dan LED. Kemudian dibuat model-model untuk OLED dan LED. Model OLED terdiri dari lapisan Hole Transport Layer (HTL) dan Electron Transport Layer (ETL). Model LED berbasis pada material Gallium Arsenide (GaAs) yang terdiri dari lapisan p dan n.Simulasi numerik yang membandingkan OLED dan LED pada diagram tingkat energi, rapat carrier, space charge, medan listrik, dan rapat arus mendemonstrasikan perbedaan pokok antara OLED dan LED. Hasil simulasi OLED dan LED yang telah didapat, kemudian dibandingkan dengan sel surya organik (OPV) dan sel surya anorganik (IPV).Dari simulasi diagram tingkat energi OLED dan LED, terlihat bahwa sambungan pn yang terbentuk pada bahan anorganik (disebut juga ?junction? = 0,2000 µm) lebih lebar daripada sambungan pn bahan organik (disebut juga ?recombination region? = 0,0002 µm). Recombination region yang sangat tipis diakibatkan oleh konsentrasi doping acceptor dan donor pada HTL dan ETL yang sangat rendah, yaitu hanya 1,40 x 105 cm-3.

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The progress of Light Emitting Diodes (LEDs) lead to higher power and efficiency. Nowadays, there are a lot of LEDs made of organic material, named Organic Light Emitting Diodes (OLEDs). OLEDs has some advantages compared to LEDs, namely wider electro-luminance display, colorful emission, higher luminance efficiency, and a lot of organic molecule available.Mechanical instability of organic material makes some disadvantages appear in OLEDs, for instance: lower temperature of transition glass. Instability also causes decreasing of material lifetime. Besides that, low mobility of organic also limits the performance of OLEDs.The basic theory that is useful to compare OLEDs and LEDs was reviewed. The models of OLEDs and LEDs were made. OLEDs model consisted of HTL (Hole Transport Layer) and ETL (Electron Transport Layer). LEDs model based on Gallium Arsenide (GaAs) consisted of p and n. Numeric simulation that compared OLEDs and LEDs in the band diagram, carrier density, space charge, electric field, and current density demonstrate the differences of those two devices. Then, the simulation result was compared to organic solar cell (OPV) and inorganic solar cell (IPV).From the band diagram simulation of OLED and LED, it was concluded that pn junction width in inorganic material (called ?junction? = 0,2000 µm) is wider than organic (?recombination region? = 0,0002 µm). Thin recombination region of OLED is due to the doping concentration of acceptor and donor at HTL and ETL are very low, i.e. 1,40 x 105 cm-3."