An Investigation Of The I-V Characteristics And Collection Efficiency For A-Si:H Tandem Solar Cells Interconnected By Transparent Conductive Oxide
| dc.contributor.author | Darkwi, Ali Yaskwi | |
| dc.date.accessioned | 2016-10-06T03:15:13Z | |
| dc.date.available | 2016-10-06T03:15:13Z | |
| dc.date.issued | 1996-10 | |
| dc.description.abstract | Obtaining stable high efficiency solar cells is one of the basic problems in hydrogenated amorphous silicon (a.Si:H) solar cell technology. A multijunction tandem solar cells design has been found to be most effective in improving cell performance. The electrical interconnection between the cells in tandem structure is one of the factors limiting the performance of the device. The behavior of solar cell is usually predicted through the analysis of current density voltage (J-V) relation. A new method has been introduced in the analysis of J-V curve for tandem structure which shows that the output current has a bias voltage dependence. For this analysis, the U-shape distribution of density of states in the energy gap was used to find the charge density in the depletion region. The electric field obtained by solving Poisson's equation shows that, the electric field is higher at the p/i and iln interface while is low near the middle of the i-layer. Under the assumption that the current in the i-layer is due to the minority carrier of the holes and collection of photo-carrier in the low field region is due to diffusion, the J-V curve was found analytically. The calculations showed that the efficiency increases by increasing the diffusion length. Numerical solution of the non-linear second order differential equation for transport equations ( Poisson's equation and continuity equations ) for charge carriers in p-i-n a-Si:H solar cell was carried out using a FORTRAN program. Since these equations are boundary-value problems, the finite difference method with Newton iteration process was used to solve the equations simultaneously. The current density obtained has a bias voltage dependence. The open circuit voltage of the device can be precisely determined from the graph rather than from the conventional equation {Voc=nkT/q In[(Jsc/Jo)+1] } which is often used, however it does not show voltage dependence. The simulation developed here provides' flexibility in the choice of physical parameters so that different models can be evaluated and compared for development of high-efficiency photovoltaic devices. A new method has been introduced for simulation of reflectance, transmittance and absorbance as a function of wavelength of incident photons in tandem solar cells. In this case transparent conductive oxide (TeO) was used as interconnection between the cells. Col/ection efficiency was calculated for different thicknesses of titanium dioxide (Ti00. The aim of this simulation is to find the effect of Ti02 in the spectral absorbance. For small thicknesses of Ti02• there is no significant reduction in the total spectral absorbance of the tandem cells. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/2683 | |
| dc.subject | A multijunction tandem solar cells | en_US |
| dc.subject | Most effective in improving cell performance | en_US |
| dc.title | An Investigation Of The I-V Characteristics And Collection Efficiency For A-Si:H Tandem Solar Cells Interconnected By Transparent Conductive Oxide | en_US |
| dc.type | Thesis | en_US |
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