Judul: Photovoltaic Effect In A CdS/P3HT-Chitosan Junction
Abstrak: A CdS/Polymer junction has been fabricated and it’s photovoltaic effect has been studied. The polymer is a blend of poly-3hexyltiophene (P3HT), chitosan and polyethileneglicol (PEG). Boron in situ doping of CdS using Chemical Bath Deposition (CBD) was investigated. The effect of B-doping and annealing on optical properties as well as on electrical and morphology of CdS film were studied. The structure and morphology of the film were detected by XRay Diffraction (XRD) and Scanning Electron Microscopy (SEM). The polymer film was sandwiched between the CdS semiconductor and an ITO glass to form an ITO/CdS/Polymer/ITO photovoltaic cell. Time constant (τ) and open circuit voltage (Voc) were investigated by using voltage censor. The bandgap of films were determined using absorbance edge method. The results of annealing optical bandgap of undoped CdS shifted from 2,49 eV down to 2,39 eV. Phase transition of CdS due to annealing temperature and induced lattice damage due to doping. The room temperature conductivity of polymer is 3,8 – 6,6 x 10-7 S/cm as function of frequency between 100 – 5000 Hz. The Voc of the fabricated cells ranges between 107 – 286 mV and time constant ranges between 2,5 to 43,75 s.
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Judul: DFT Study on the Effect of In Vacancy-Point Defect and Ag+ Doping on Properties of Cs2ScInCl6 Double Perovskite as Solar Cell Candidate
Abstrak: Perkembangan konsumsi energi global yang terus meningkat mendorong pemanfaatan sumber energi terbarukan seperti energi matahari dalam transformasi menjadi energi listrik, seperti teknologi fotovoltaik dinamakan sel surya. Pemanenan energi surya dengan teknologi ini dapat menggunakan Double Perovskite (DP) sebagai material yang dapat menyerupai kinerja perovskit berbasis timbal (Pb). Akibat Pb yang memiliki permasalahan dari sisi toksisitasnya, kemudian dilakukan uji DP Cs2ScInCl6 dengan mengeksplorasi sifat elektronik dan optiknya secara komputasi menggunakan DFT. Selain itu, untuk mendapat perbaikan performansi dapat dilakukan dengan memodifikasi strukturnya berupa pengadaan vacancy-point defect (x = 0,25) dan kombinasi vacancy-point defect dan doping ion Ag+ serta variasi metode Spin Orbit Coupling (SOC) dan tanpa SOC. Cs2ScIn1-0,25Cl6 tanpa SOC memiliki performansi yang baik ditinjau dari sifat elektroniknya. Sedangkan ditinjau dari keseluruhan terlepas dari transisinya Cs2ScIn1-0,25Ag0,25Cl6 tanpa SOC memberikan performansi paling baik sebagai kandidat sel surya DP Cs2ScInCl6 dilihat dari gap-nya yang berkaitan dengan kemampuan absorbsi foton dengan spektrum yang lebar., The development of global energy consumption that continues to increase encourages the use of renewable energy sources such as solar energy in the transformation into electrical energy, such as photovoltaic technology called solar cells. Solar energy harvesting with this technology can use Double Perovskite (DP) as a material that can resemble the performance of lead-based perovskite (Pb). As a result of Pb which has problems in terms of toxicity, then the DP Cs2ScInCl6 test was carried out by exploring its electronic and optical properties computationally using DFT. In addition, to get improved performance can be done by modifying the structure in the form of procurement vacancy-point defect (x = 0,25) and a combination of vacancy-point defect and doping ion Ag+ and variations of Spin Orbit Coupling (SOC) and no SOC methods. Cs2ScIn1-0,25Cl6 without SOC has good performance in terms of its electronic properties. While in terms of overall regardless of the transition Cs2ScIn1-0,25Ag0,25Cl6 without SOC gives the best performance as a candidate DP solar cell Cs2ScInCl6 seen from itsgap related to the absorption ability of photons with a wide spectrum.
Keyword: Bandgap, DFT, Double Perovskite, Transition, Vacancy-Point

Judul: Sebaran dan Asosiasi Gastropoda di Rataan Terumbu Kepulauan Derawan Kalimantan Timur.
Abstrak: Gastropoda di rataan terumbu merupakan salah satu potensi sumberdaya perikanan yang besar, mengingat gastropoda terbanyak hidup di laut dangkal. Gastropoda sebagai sumberdaya dapat dimanfaatkan, hewannya sebagai sumber protein dan cangkangnya sebagai cendera mata dan bahan baku industri. Gastropoda merupakan kelas dari filum Moluska yang memiliki anggota terbanyak dan tersukses hidup di berbagai habitat di bumi ini (Russel dan Hunter, 1983). Gastropoda terdiri dari tiga kelompok besar (subkelas), yaitu: Prosobranchia, Ophistobranchia dan Pulmonata. Prosobranchia merupakan kelompok terbesar dari gastropoda yang terdiri dari tiga ordo, yaitu: Archaeogastropoda, Mesogatropoda dan Neogastropoda (Hughes, 1986).
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