PENDISTRIBUSIAN DAN PENJERNIHAN AIR DI DESAGIRIHARJO KECAMATAN PANGGANG KABUPATEN GUNUNG KIDUL

Giriharjo Village at panggang District, Gunungkidul Regency was a village that had clean water supply problem. Its villagers, having a monthly income in average of Rp 400.000,00, must spend around Rp 150.000,00 for clean water or otherwise they must walk to get water from Kaligede River 2 -4 km away from their home. Inorder to alleviate this problem, two separate team as parts of student community service program (KKN-PPM) UGM have been deployed on July-August 2008 and July-August 2009. As the result, a system of clean water supply using Solar Water Pumping System (SWPS) has been installed since the end of August 2009. However, there is no reliable distribution and purification system to provide equal access of clean water for the entire village. On the other hand, the system\u27s frequent shutdowns caused by technical problems also became the main concern for the future program. The third student team was deployed on July-August 2010 to perform the remaining tasks. This team has successfully established a reliable distribution system. However, the water purification system has not been installed yet. There was a delay on the development of the water filtration prototype. The SWPS technical problems have been solved with the assistance of PAMMASKARTA, a Non Governmental Organization on water supply system for rural areas in Yogyakarta

Optimasi Pembentukan Lapisan Boron P+ pada Permukaan Belakang Sel Surya untuk Peningkatan Efisiensi Sel Surya berbasis Wafer Silikon Monokristal

Efisiensi sel surya dapat ditingkatkan dengan mengurangi rekombinasi pada permukaan belakang dari sel surya. Salah satu strategi yang dapat digunakan untuk mengurangi rekombinasi pada permukaan belakang adalah dengan mengurangi konsentrasi pembawa muatan minoritas di bagian permukaan belakang sel surya. Kondisi ini dapat dicapai dengan membuat lapisan boron p+ pada permukaan belakang sel surya yang memiliki konsentrasi lebih tinggi daripada basis dan memiliki tipe doping yang sama, dikenal sebagai lapisan boron -back surface field (B-BSF). Saat ini berdasarkan kecenderungan eksperimental, didapatkan bahwa peningkatan konsentrasi doping dan ketebalan lapisan B-BSF akan meningkatkan efisiensi sel surya. Akan tetapi, pada proses fabrikasi B-BSF eksperimental, ditemukan bahwa meningkatkan ketebalan lapisan BSF sangat sulit dan meningkatkan biaya. Oleh karena itu diperlukan studi untuk menganalisis sampai batas mana usaha untuk meningkatkan ketebalan lapisan BSF secara eksperimental dapat memberikan peningkatan nilai efisiensi yang memadai untuk digunakan pada industri sel surya di masa depan. Pada penelitian ini telah dilakukan analisis secara simulasi, pengaruh ketebalan dan konsentrasi lapisan boron BSF terhadap efisiensi pada sel surya berbasis wafer silikon monokristal. Simulasi dilakukan menggunakan perangkat lunak PC1D. Simulasi dilakukan pada wafer 300 mikron dengan doping dasar tipe-p 1,50x1016/cm3 dan emitter tipe-n dengan ketebalan 1,56 mikron dan konsentrasi doping 7,5x1018/cm3 yang memiliki efisiensi 16,30%.Hasil simulasi menunjukkan bahwa secara umum semakin tebal lapisan boron p+ dan semakin tinggi konsentrasi dopingnya, efisiensinya akan semakin meningkat. Pengecualian terdapat pada ketebalan lapisan diatas 220 mikron dan konsentrasi diatas 1,26x1019/cm3. Hasil ini sesuai dengan kecenderungan eksperimental dan memprediksikan bahwa kecenderungan ini akan berlanjut sampai nilai ketebalan lapisan BSF yang sangat ekstrim. Akan tetapi ditemukan bahwa laju peningkatan efisiensi terhadap peningkatan ketebalan lapisan BSF mengalami penurunan secara signifikan setelah ditingkatkan melebihi ketebalan 20 mikron. Selanjutnya optimasi dilakukan untuk memaksimalkan efisiensi sel surya terhadap variasi dari ketebalan dan konsentrasi. Ditetapkan tiga pembatas yakni konsentrasi doping, ketebalan lapisan dan peningkatan efisiensi marjinal terhadap peningkatan ketebalan lapisan. Untuk konsentrasi doping NBSF dibatasi 1017/cm3≤NBSF≤1020/cm3 dan ketebalan lapisan WBSF dibatasi sampai 20 mikron. Sebagai pertimbangan kompromi antara usaha untuk peningkatan efisiensi dan kemudahan dalam pembuatan lapisan BSF, ditetapkan bahwa nilai optimum harus memberikan peningkatan efisiensi marjinal terhadap peningkatan ketebalan lapisan lebih besar atau sama dengan 0,01%/mikron. Optimasi matematis dilakukan dengan metode brute force search. Berdasarkan hasil optimasi, direkomendasikan untuk meningkatkan ketebalan lapisan boron hingga 20 mikron dan meningkatkan konsentrasi sampai 3,40x1018/cm3. Apabila rekomendasi desain dapat dipenuhi, efisiensi sel surya dengan boron p+ dapat ditingkatkan hingga 17,58%

Voltage transient analysis as a generic tool for solar junction characterization

International audienc

Silicon heterojunction solar cell based on organic and transition metal oxide selective carrier contact layer

Si heterojunction solar cells based on organic and transition metal oxide selective carrier contact layer are developed to bypass the high-temperature process required for the conventional Si solar cell. We investigated the behavior of n-Si/PEDOT:PSS inorganic-organic heterojunction which revealed a p-n junction characteristic in contradiction with Schottky junction model. Afterward, we developed a simulation model to optimize n-Si/PEDOT:PSS heterojunction solar cells. We propose the use of simple front junction PEDOT:PSS (30 nm) / Si3N4 (40 nm) layer that can achieve efficiency of 18.4% and more complicated interdigitated back contact design that can achieve 20.4%. We fabricate Si/molybdenum oxide heterojunction solar cell structure which can yield high short circuit current density of 34.3 mA/cm2 although the efficiency is limited to 11.6%. Moreover, we propose and analyze the potential of PV-Tower solar cell concept which can generate high power improvement factor over a small footprint.Doctor of Philosophy (EEE

Analysis of Performance, Carbon Emission, and Economics on the Design of Floating Photovoltaic in Sambinasi Village, East Nusa Tenggara

East Nusa Tenggara (ENT) Province has the highest solar energy potential in Indonesia, but also it had the lowest electrification ratio in 2021. Solar Power Plants (SPP) based on Floating Photovoltaic (FPV) can be used to meet electricity needs in ENT while avoiding land use problems and various environmental issues related to Ground-mounted Photovoltaic (GPV). In this paper, the performance, carbon emission, and economics analysis of FPV in Sambinasi Village, ENT, were carried out to compare FPV and GPV with similar specifications. Due to the effect of natural cooling, for a 32.9 MWp photovoltaic system, FPV has 0.63 GWh/year higher energy production, 0.11% higher efficiency, 0.22% higher Capacity Factor (CF), and 0.99% higher Performance Ratio (PR) in comparison to GPV. Using the typical fossil-based power plant emission in Indonesia as the baseline, FPV has 511.61 – 565.06 tons CO2/year greater carbon emission reduction than GPV. Regarding its economic feasibility, FPV has IDR 47,018,294,731 smaller Net Present Value (NPV), 7 months slower Payback Period (PP), 0.1 smaller Profitability Index (PI), and 1.18% smaller Internal Rate of Return (IRR)

Design guideline for Si/organic hybrid solar cell with interdigitated back contact structure

We study the design of Si/organic hybrid (SOH) solar cells with interdigitated back contact (IBC) structure. SOH solar cells formed between n-Si and poly(3,4-ethylenedioxythiophene): polystyrenesulphonate (PEDOT:PSS) is a promising concept that combines the excellent electronic properties of Si with the solution-based processing advantage of an organic polymer. The IBC cell structure is employed to minimize parasitic absorption losses in the organic polymer, eliminate grid shadowing losses, and allow excellent passivation of the front Si surface in one step over a large area. The influence of Si thickness, doping concentration and contact geometry are simulated in this study to optimize the performance of the SOH-IBC solar cell. We found that a high power conversion efficiency of >20% can be achieved for optimized SOH-IBC cell based on a thin c-Si substrate of 40 μm thickness

High efficiency silicon nanowire/organic hybrid solar cells with two-step surface treatment

A simple two-step surface treatment process is proposed to boost the efficiency of silicon nanowire/PEDOT:PSS hybrid solar cells. The Si nanowires (SiNWs) are first subjected to a low temperature ozone treatment to form a surface sacrificial oxide, followed by a HF etching process to partially remove the oxide. TEM investigation demonstrates that a clean SiNW surface is achieved after the treatment, in contrast to untreated SiNWs that have Ag nanoparticles left on the surface from the metal-catalyzed etching process that is used to form the SiNWs. The cleaner SiNW surface achieved and the thin layer of residual SiO2 on the SiNWs have been found to improve the performance of the hybrid solar cells. Overall, the surface recombination of the hybrid SiNW solar cells is greatly suppressed, resulting in a remarkably improved open circuit voltage of 0.58 V. The power conversion efficiency has also increased from about 10% to 12.4%. The two-step surface treatment method is promising in enhancing the photovoltaic performance of the hybrid silicon solar cells, and can also be applied to other silicon nanostructure based solar cells.Accepted versio

Nanostructured back reflectors produced using polystyrene assisted lithography for enhanced light trapping in silicon thin film solar cells

We study light trapping in hydrogenated amorphous silicon thin film solar cells fabricated by plasma-enhanced chemical vapor deposition on various nanostructured back reflectors. The back reflectors are patterned using polystyrene assisted lithography. We have investigated the correlation between the back reflector optical properties and the corresponding solar cell performance. We have introduced double size polystyrene sphere patterned back reflectors and have provided experimental evidence for improved light trapping performance compared to single size polystyrene sphere patterned back reflectors. We have achieved high performing nanostructured amorphous silicon solar cells with an initial power conversion efficiency of 7.53% and over 20% enhancement of the short-circuit current compared with the reference flat solar cell

Totally embedded hybrid thin films of carbon nanotubes and silver nanowires as flat homogenous flexible transparent conductors

There is a great need for viable alternatives to today’s transparent conductive film using largely indium tin oxide. We report the fabrication of a new type of flexible transparent conductive film using silver nanowires (AgNW) and single-walled carbon nanotube (SWCNT) networks which are fully embedded in a UV curable resin substrate. The hybrid SWCNTs-AgNWs film is relatively flat so that the RMS roughness of the top surface of the film is 3 nm. Addition of SWCNTs networks make the film resistance uniform; without SWCNTs, sheet resistance of the surface composed of just AgNWs in resin varies from 20 Ω/sq to 107 Ω/sq. With addition of SWCNTs embedded in the resin, sheet resistance of the hybrid film is 29 ± 5 Ω/sq and uniform across the 47 mm diameter film discs; further, the optimized film has 85% transparency. Our lamination-transfer UV process doesn’t need solvent for sacrificial substrate removal and leads to good mechanical interlocking of the nano-material networks. Additionally, electrochemical study of the film for supercapacitors application showed an impressive 10 times higher current in cyclic voltammograms compared to the control without SWCNTs. Our fabrication method is simple, cost effective and enables the large-scale fabrication of flat and flexible transparent conductive films.ASTAR (Agency for Sci., Tech. and Research, S’pore)Published versio

Optical Study and Experimental Realization of Nanostructured Back Reflectors with Reduced Parasitic Losses for Silicon Thin Film Solar Cells

We study light trapping and parasitic losses in hydrogenated amorphous silicon thin film solar cells fabricated by plasma-enhanced chemical vapor deposition on nanostructured back reflectors. The back reflectors are patterned using polystyrene assisted lithography. By using O2 plasma etching of the polystyrene spheres, we managed to fabricate hexagonal nanostructured back reflectors. With the help of rigorous modeling, we study the parasitic losses in different back reflectors, non-active layers, and last but not least the light enhancement effect in the silicon absorber layer. Moreover, simulation results have been checked against experimental data. We have demonstrated hexagonal nanostructured amorphous silicon thin film solar cells with a power conversion efficiency of 7.7% and around 34.7% enhancement of the short-circuit current density, compared with planar amorphous silicon thin film solar cells