Study Of Design And Experiment Of Silicon Thin Film Solar Cells Near-infrared Cut-off Filter

As one of the most competitive role of the "second generation" photovoltaic devices, Silicon thin film solar cells have many advantages:non-toxic and pollution-free, wide material sources, well developed preparation technology, et al. In recent years, most of the commercial photovoltaic cells are based on silicon, this kind of solar cells are mainly divided into crystalline silicon and thin film silicon categories. Since the raw material is silicon, the solar cells’ operating bandwidth are basically in the range of400-1100nm, it means that most of the near-infrared light energy photons will not be absorbed to generate electron-hole pairs. And the near-infrared light has a strong heat radiation effect, the operating temperature of the battery rises and thereby reduces the power output.For these reasons, we design a near-infrared cut-off filter, it will filter the near-infrared waves without affecting the normal operating wave band. In recent years, one-dimensional photonic crystal have been widespread concerned both in theory and experiment because of its simple structure, easy to prepare and has a near perfect photonic band gap Omni-directional reflection band. In this thesis, we will mainly study how to design the filter using the simplest photonic crystal structure, in ensuring the solar cell work bandwidth is not affected to maximize the cut-off bandwidth of near-infrared spectroscopy, specific simulation and experimental procedures are as follow:Firstly, we will use the transfer matrix method (Transfer Matrix Method, TMM) to study the transmission characteristics of a uniform plane wave across the multilayer structures. Then use MATLAB programming, call TMM algorithm, set the photonic crystals materials parameters, to get the transmission spectra in the range of400-2000nm. We will analyze the impact of the refractive index of the photonic crystal material and the number of cycles of photonic crystals, obtain the simplest one-dimensional photonic crystal filter structure, and the bandwidth is about1051.6nm-1594.4nm.Secondly, in order to verify the reliability of our theoretical design, we have prepared the filter structure by magnetron sputtering (Pecs682sputter coater). Then the samples were characterized, we used a scanning electron microscope JSM-6510to scan cross-section and lambda750UV/VIS/NIR to measure transmittance spectra, and then compare with the results of the simulation.Finally, we will theoretically analyze the potential application of the near-infrared cut-off filter in solar cells.