Browsing by Author "Rahman, Muhammad Lutfor"

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Design and development of CsSnI3 solar cell using SCAPS-1D simulation
(BRAC University, 2024-08) Haque, Md. Firoze H.; Rahman, Muhammad Lutfor
"Solar cells are popular because they offer a clean, renewable way to produce elec- tricity from sunlight without harming the environment. Recently, lead-based per- ovskites have been used in the absorber layer in the construction of solar cells due to their ability to absorb light, high carrier mobility, and tunable band gap. However, lead is known to be toxic, posing safety challenges for the environment. To address this problem, extensive research is being conducted to find alternatives, such as de- veloping safer lead-free perovskites. This study proposes a model for a lead-free solar cell consisting of a cesium tin io- dide perovskite in the absorber layer. A simulation was conducted using SCAPS-1D software, which allows users to create a model and analyze its various properties. Indium Tin Oxide (ITO) was chosen as the transparent conducting layer. [6,6]- Phenyl-C61-butyric acid methyl ester (PCBM), an organic compound, was chosen as the electron transport layer (ETL), and Copper Iron Tin Sulfide (CFTS) was used for the hole transport layer (HTL). Cesium Tin Iodide (CsSnI3) was used as the absorber layer, which was sandwiched between the ETL and HTL. Lastly, gold (Au) was used to serve as contacts between the layers. Once the device was modeled, several parameters, such as the thickness of each layer, doping concentrations, electron affinities, and temperatures, were varied to study their impact on power conversion efficiency (PCE), fill factor (FF), open- circuit voltage (Voc), and short-circuit current (Isc). The simulation indicated that the maximum obtained power conversion efficiency stood at 26.9% for this device at a temperature of 298 K by optimizing these param- eters. The results demonstrate that the device is a promising alternative to both the current market-available solar cells and lead-based perovskite solar cells."
Development of a low cost MPPT circuit for Solar Panel
(BRAC University, 2014-09) Azim, Syeda Mayesha; Rahman, Muhammad Lutfor
Renewable energy source have potential of playing a vital role in electricity generation. In Bangladesh, solar panel is now a widely used renewable energy source. So extracting maximum power from solar panel is vital. In order to maximize the output from a solar panel maximum peak power tracker (MPPT) should be introduced. This paper describes the design and development of a low cost MPPT circuit for extracting maximum power from the solar panel and charging a storage battery. The designed circuit consists of a microcontroller (PIC16F72) which generates high frequency pulse signal of different widths in accordance with the output of solar panel and electrical characteristics of the load to operate the panel at maximum power point. The generated pulse signal drives a DC-DC Buck-Boost converter which gives constant voltage of 15V to the battery ensuring optimum energy being extracted from the solar panel. The microcontroller controls the operation of the system according to the codes burned in it, which had been developed in MPLAB IDE.
Internship on (Ni0.4Cu0.15Zn0.45)1-xMnxFe2O4 sample preparation and calcination
(BRAC University, 2017) Mridula, Zarrin Tasnim; Rahman, Muhammad Lutfor
The sole purpose of this internship is to provide us hands on experience on how to measure, prepare and characterise a sample of the (Ni0.4Cu0.15Zn0.45)1-xMnxFe2O4 ferrites (x=0.3, x=0.45) which was further hand milled before and after calcination to achieve a homogenous distribution. In order to prepare the sample, the stoichiometric ratio was found, and then the exact amount of each required compound was measured separately using an AX120 electronic balance as it provides a high precision of 10 micrograms. It has a full range tare to allow unladed weight measurement. It was hand milled with a pestle and mortar and finally calcined at 950°C and sintered at 1100°C in air for 5 hours at 1100, 1150 and 12000C using a Nabertherm p330 to drive off water, carbon dioxide, and other volatile constituents and to oxidise the whole composite. Structural and magnetic properties of were investigated and it was prepared by solid state reaction methods.
Investigation of IV characteristic of semiconductor diode and resistor using keithley 2450 source meter operated by labview programming
(BRAC University, 2019) Mustafa, Anjum; Rahman, Muhammad Lutfor
This internship report mainly focuses on Investigating the IV characteristic curve of diode and resistor using Keihley 2450 source meter operated by lab view programming. Using the Lab view programming such configuration was made where voltage is supplied and the corresponding current had been calculated for several points for both diode and resistor. A voltage versus Current graph was plotted using Origin lab according to the data from the setup and was investigated and compared with the theoretical properties of the diode and resistor with authentic reference. The measured data followed the theory and almost gave the same characteristic curves which proves that the programming in Labview and the setup in Keithley 2450 source meter was accurate for the measurement.
Measurement and analysis of temperature dependent resistance of 𝑳𝒊𝒙𝑪𝒖0.5𝒁𝒏𝟎.𝟓−𝟐𝒙𝑭𝒆𝟐+𝒙𝑶4
(BRAC University, 2023) Jajayare, MD.Jabar Al; Haque, Md.Firoze H.; Rahman, Muhammad Lutfor
The DC electrical property of 𝑳𝒊𝒙𝑪𝒖0.5𝒁𝒏𝟎.𝟓−𝟐𝒙𝑭𝒆𝟐+𝒙𝑶4 (x=0.00, x=0.05, 0.10) samples prepared by solid state reaction method was investigated. The samples were calcined at 800℃ and sintered at 1000℃ and 1050℃ respectively in air for 5 hours. The samples were placed in an electric oven and the corresponding resistance and temperature measurement were taken using 2 probe method by keithley 2450 and 6517b respectively. The resistance was found to decrease as the value of x increased and also increasing temperature showed semiconductor behaviour of the samples
Ni0.48Cu0.12Zn0.40Gd0.04Fe1.96O4 (Ferrite) sample preparation, planetary ball milling and calcination
(BRAC University, 2017-06) Noor, Lamisha; Rahman, Muhammad Lutfor
The purpose of the internship was to provide with a firsthand experience on how to measure and prepare a precise amount of the ferrite composite, Ni0.48Cu0.12Zn0.40Gd0.04Fe1.96O4 which was then further planetary ball milled for fourteen hours to achieve homogeneous distribution at 230 rpm, hand milled for a further four hours in two separate sessions using an agate pestle and mortar and finally calcined at 950℃ afterward using a Nabertherm p330 to drive off water, carbon dioxide, other volatile constituents and to oxidize the whole composite. In order to prepare the sample, first the stoichiometric ratio was found and then the exact amount of each required compound was measured separately using an AX120 electronic balance as it provides a high precision of 10 μg and has a full range TARE to allow unladen weight measurement. Planetary ball mill was used for grinding to ensure quick contamination free grinding down of the prepared sample to nano range. Nabertherm P330 was used for calcination as it can be functioned to allow and ensure easy setting of temperature values, time specifications and gradient specifications. These were crucial as the calcination process required the buildup of temperature over a span of two hours in intervals of 10℃ up to 950℃, held at that for five hours and then cooled back in instalments of 5℃. The final product was again ball milled to get rid of clusters and turned into powder thereby completing the preparation of the ferrite sample.
Optical characterisation of single junction monocrytalline silicon solar cell
(BRAC University, 2015-01) Tonima, Masuda Akter; Rahman, Muhammad Lutfor
In this paper the character of a solar cell in terms of minority carrier diffusion length through surface photovoltage (SPV) technique is studied. SPV is measured with respect to wavelength where the spectral range is 400-1200 nm. A 200 μm thickness of 3″ X 3″ mono-crystalline silicon solar cell is used for the calculation purpose; through which the values of total carrier generation and recombination during illumination are found. For the range, 700-1000 nm wavelength penetration depth of the cell can be found. This helps in plotting of a curve that eventually gives us the value of carrier diffusion length which also helps in determining minority carrier lifetime of the cell, short circuit current density, optimum value of generation etc. For further study of the cells character, an efficiency test and an external quantum efficiency test is done via pre-set instruments built for the specific purpose, which helps in further confirmation of the quality of the fabricated cell.
Permeability measurements of Ni0.4Cu0.15Zn0.45Fe2O4 using impedance analyzer
(BRAC University, 2017) Shara, Afrin Jahan; Rahman, Muhammad Lutfor
This internship presents the work of Ni0.4Cu0.15Zn0.45Fe2O4 sample preparation and its permeability measurements at different sintering temperature using 6500B impedance analyzer. Firstly ‘’Ni0.4Cu0.15Zn0.45Fe2O4‘’ sample were being prepared by using different materials according to their stoichiometric ratio using an electronic balance. The sample were then hand milled for 5 hours to gain a homogenous distribution and to remove impurities as much as possible by using an agate pestle and mortar. After that the sample was calcined at 950oC using a furnace to eradicate water, oxides. To achieve a more pure and uniform sample, it was hand milled for more 2 hours until the powder is finely mixed. Afterwards the sample was made into three disk and ring shapes for three sintering temperatures (Ts). Once the sintering is finished the disks and rings were ready to be analyzed. The ring shaped samples were examined by the impedance analyzer (Wayne Kerr 6500B Precision Impedance Analyzer) to calculate the permeability of the samples, the frequency to which the sample can operate.
Simultaneous interface application development for an electrometer and a source meter using LabVIEW to study three terminals semiconducting device
(BRAC University, 2018-09) Ratul, Mahadi Hassan; Haque, Firoze H.; Rahman, Muhammad Lutfor
A transistor is an electrical device made of semiconductor material that is used for operations such as amplification and switching of electronic signals and electrical power. A transistor to be used effectively and perform it’s full functions as amplifiers and switches, it is important to know its characteristics, electrical properties and operational specifications, it needs to be adaptable to the circuit’s current/voltage limits and other operating conditions. There are many types of transistors, such as Bipolar Junction Transistor (BJT) and Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET), are used extensively in electrical circuits in applications for a diverse range of electrical devices. An electrometer is a device which is a measuring instrument with various applications and can be used to measure the current readings of a transistor subjected to different levels of input voltages. For the electrometer to function most efficiently, an application is made using LabVIEW software which allows for its remote access to accomplish functions such as conducting a voltage sweep (applying incremental voltages after short delays and recording the current). As the program is software controlled, it decreases the data acquisition time drastically and eliminates the factor of human error the source meter is used to apply different amount of voltages at the gate terminal of the transistor and the electrometer measures the different drain current values. Such a program, coupled with the electrometer and source-meter, promotes an efficient way of making a voltage sweep and displaying a graph of the input voltage and output current from the data obtained simultaneously. This enables us to characterize the transistors and the data can be used to identify whether the transistor can be used in a particular system or circuit.
Study of Titanium, Vanadium, Chromium and Manganese doped lead free double perovskites Cs2NaGaBr6 for potential solar cell
(BRAC University, 2024-03) Hussain, Ahmed Zabir; Haque, Md. Firoze; Rahman, Muhammad Lutfor
Lead-free inorganic double perovskites are making notable progress in the field of solar cells and optoelectronic devices. Promising materials such as Cs2NaGaBr6 are emerging as competitive alternatives. This research work studied the structural, electronic, and optical properties of pristine Cs2NaGaBr6 and Vanadium (V), Titanium (Ti), Chromium (Cr), and Manganese (Mn), doped sample, applying density functional theory for our analysis. This study is the first theoretical exploration of the doped Cs2NaGaBr6 perovskites, uncovering extraordinary results. The study reveals that all versions with added impurities show enhanced optical absorption and high optical conductivity, covering wavelengths of the visible spectrum. The wide range of performance is especially important for optoelectronic applications since it indicates greater effectiveness in absorbing solar energy. The study analyzed the electronic properties of Cs2NaGaBr6 perovskites, revealing significant changes in the band gap for each doped variation. This allows for precise tuning of the band gap, enhancing solar energy absorption. The study also found a higher density of accessible electronic states around the fermi level in doped samples, indicating increased electrical and optical conductivity. The results suggest that doping can be used to customize and enhance optical and electronic properties, creating opportunities for advanced solar cells and sustainable energy solutions.