The relationship between Solar Cell and Chemical Engineering
Researchers aim at developing technologies that will see high-performance solar cells with reduced cost per watt generation. The focus is on the mass production of relatively cheap, long-lasting solar cells composed wholly of solid-state components. Dye-sensitive solar cells are an option for crystalline semiconductor photovoltaic. They consist of cheaper porous titanium dioxide nano-particles consisting of a dye absorbing sunlight coat that usually touches the liquid electrolyte.
The dye-sensitive solar cells have low-cost manufacturing processes. However, they lack long life and durability which is a factor of the corrosive solution that is highly volatile and likely to leak and also high probability of reacting with the dye. This has prompted researchers to devise a method of replacing the liquid electrolyte with a non-corrosive solid-state match.
A group of researchers at Purdue University are working towards coming up with an alternative solution to photovoltaic advancement through producing cheap solar cells. This will utilize some special ink on supporting materials. The team of engineers is driving massive producing solar cells at low cost. They see the possibility through making special ink using nanocrystal made of copper, zinc, tin and sulfide (CZTS). The availability of CZTS makes the printing process of the photovoltaic cells is not expensive when using ink.
For the innovation to match the current technology, the solar cells should have the capacity of yielding terawatts of electricity at 50 cents per peak watt. The procedure for developing solar cells entails making nanocrystals, carefully devising the ink and printing it on a flexible supporting material. As the ink moves, the solar cells catch the heat to temperatures of 500 degrees Celsius to combine the nanoparticles. The ink technology assures a reduced cost of the solar cells and offers them a long life.
Solar simulator tester: How the Instrument is working, what is the data extracted, advantages and disadvantages
The solar Cell Efficiency technique looks at various compositions (semiconductors) of solar cells. Producing a solar cell involves doping or contaminating a semiconductor to produce either positive or negative charge carriers from semiconductor materials. In practical application, solar cell efficiency looks at the “ratio between electric power delivered to the load and incident of the light intensity” (Lewis Research Center 40).
Solar simulator tester gauges and sorts photovoltaic cells. Modern solar simulator testers based on computer applications measure the electric performance of photovoltaic cells under simulated sunlight. It also monitors the intensity of the sunlight.
Solar simulator tester measures and shows some of these cell aspects. These include open-circuit voltage (Voc), cell efficiency, fill factor (FF), short-circuit current (Isc), complete I-V curve, peak power (Pmp), cell temperature (0C), shunt resistance (Rsh), short-circuit current density (Jsc), and series resistance (Rs).
The data obtained falls under measurement parameters of IV curve, Isc, Voc, Im, Vm, Pm, FF, RS, EFF. Modern solar simulator tester has the benefit of providing consistent illumination on the solar cell, and they can reduce the built up of the heat and prolong the life of the solar cells. Some have multiple pointers to ensure accurate measurements. Computer-based solar simulator tester can measure perform data analysis, print the result and store the results.
However, a major challenge is that some of these solar simulator testers cannot achieve uniformity of light intensity when testing a large wafer (8 inches in diameter). Solar simulator testers are also expensive equipment. Environmental factors such as the sun angle, cells temperature, load, and sunlight intensity affect the solar cell efficiency.
Solar cell efficiency techniques show that cases of single loss mechanism where the cells do not absorb photon with too little energy, and where excess energy changes into heat are due to “inherent physical characteristics and limitation of the materials” (Global Data 4). Consequently, such cases have no chances of improvement. Hence, we have a theoretical maximum level of efficiency of approximately 28 percent in the crystal silicon.
Quantum efficiency solar cell tester: How the Instrument works, what is the data extracted, advantages and disadvantages
Quantum efficiency measurement is a key instrument for solar cells and signifies the suitability of the solar cell in conversion of sunlight to electricity. This measurement functions to examine for new cells structure and material. It also accounts for reproduction of the solar cells and modules (ASTM 24). “The ratio of the amount of charge carriers, that the solar cells collect to that of the number of photons, of a certain wave lengths shining on the solar cell” (Adla 2), is the quantum efficiency.
A quantum efficiency solar cell tester uses two sources of lights to illuminate solar cells under test. The first light is white light for the background that enhances and simulates real use situations. This is usually broadband light. The second light is controllable and tunable wavelength that illuminates the targeted cell so as to give the required narrow band stimulus. This light is monochromatic. The monochromatic light covers an area of 300 nm and 1100 nm that targets the solar cell under test. The measurement parameter for quantum efficiency solar cell tester include Voc, Isc, Vmax, Imax, Pmax, Rseries, Rshunt, FF or Fill Factor, and forward and reverse sweep feature.
In cases where the wavelength achieves a value of 100 percent, it means that cells take all the photons, and carriers collected too. Engineers consider QE photons with zero energy if it is below the band gap. In most cases the charge carriers do not to move into an external circuit, “the quantum efficiency for the solar cell goes down due to recombination effects” (Adla 2). This spells out that the same means that affect the collection probability is the same one that influences the QE.
Quantum efficiency system does cater for light that the solar cell transmits or reflects. Instead, it provides an overall value of the test. This is the fundamental area of concern in quantum efficiency testing. This implies that we must account for the losses and determine the exact cell efficiency through applying the internal quantum efficiency (IQE).
The IQE attempts to account for transmitted and reflected light in measurement such that the quantum efficiency calculation will only consider the light that the solar cell absorbs. The current voltage (I-V) measurement parameter indicates the solar cell functions in terms of electrical output.
Quantum efficiency techniques provide great flexibility necessary for solar cell research when testing both new and existing solar cells (Scanlon 2). Carefully choosing and configuring a quantum efficiency can result into measurement accuracy that is better than one percent. Recent developments have resulted into enhanced accuracy in measurement and improved duration of up to four times.
Quantum efficiency testing is useful in measuring material elements of solar cells. It can show “material band gaps and thicknesses in single and multilayer solar cells, minority carrier diffusion lengths, spectral-dependence of short circuit current, and qualitative spatial electronic behavior within cells” (Adla 2). Quantum efficiency testing collects data on cell response in a serial pattern in the panel.
Works Cited
Adla, Adnan. “Instrumentation for quantum efficiency measurement of solar cells.” Photovoltaics World (2010): 28-31. Print.
ASTM. ASTM Standard E 973M – 96. West Conshohocken, PA: American Society for Testing and Materials, 1996. Print.
Global Data. Solar Cell Efficiency – Key Determining Factor for Solar PV Market Prospects. New York, NY: MarketResearch. 2010. Print.
Lewis Research Center. High efficiency silicon solar cell review. Washington, DC: National Aeronautics and Space Administration, 1975. Print.
Scanlon, Bill. “NREL Invention Speeds Solar Cell Quality Tests.” NREL, (2011): 1-2. Print.