Research Terms
Energy Solar Energy Electro-Optics Photonics Solid State Electronics Materials Characterization Materials Testing Optoelectronic Devices
Keywords
Computational Physics And Modeling Photovoltaics Reliability Engineering Silicon Solar
Industries
Advanced Materials & Products Green Buildings Smart Grid Solar Renewable Energy Processing
Thin solar cells can offer higher performance and efficiency than standard cells, but the main technical challenge of breakage remains. Compared to standard, thicker counterparts, thin cells incur more damage when handled during the manufacturing process, thwarting high-yield manufacturing of thin solar cells.
UCF researchers have developed a method for cell production that increases manufacturing profitability because the silicon wafer is not handled until the last step. The conventional method calls for processing one side and then the other of a crystalline silicon substrate, while the new method fabricates the cell in reversed order using low temperature and atmospheric processes. With all steps performed within a single cluster tool, including bonding, the method effectively eliminates transportation challenges. Cost is further reduced by each processing step that can now be avoided.
Technical Details
This new three-step approach to fabricating thin heterojunction solar cells is based on direct Si-Si bonding. The method applies to HIT (heterojunction intrinsic thin layer) and SHJ-IBC (silicon-heterojunction interdigitated-back-contact) cells, which, when well below 100 µm thick, can reach efficiencies beyond 24%. Other prevalent cell types like PERC and selective emitter reach no more than 22% efficiency. By fully processing transparent substrates as building blocks, solar cells fabricated this way can be as thin as 20 µm with correspondingly high efficiency. Beginning with two glass substrates, the method calls for depositing a transparent conductive oxide, amorphous silicon, and intrinsic amorphous silicon, in succession. The thin crystalline silicon wafer is then sandwiched between two essentially processed transparent substrates and bonded to both substrates' amorphous silicon layers. A go-to approach in the MEMS (microelectromechanical systems) industry, Si-Si bonding can also benefit the PV industry by simplifying solar cell manufacturing through this new method.
The University of Central Florida invention is a new method of performing photoluminescence and electroluminescence characterization in the field on photovoltaic modules, strings and arrays. The method is performed in daylight and without the use of external energy sources. Furthermore, entire strings and arrays can be captured at once, which reduces cost and improves convenience.
Photoluminescence and electroluminescence are essential characterization techniques for photovoltaic cells and modules, primarily used in the laboratory. Recently, due to the valuable nature of these techniques, various research teams and companies have developed hardware to perform these techniques in the field, using mobile implementations within vans or elaborate devices mounted to the modules. They may also be aerial images at night requiring a large power supply with a bulky network of switches or modulation external LED lights or currents. In any of these cases, either expensive equipment is required, the technique is considerably slow and demands a significant amount of manpower, or the technique requires a nighttime measurement with many hazards that come with working in the dark.
Partnering Opportunity
The research team is seeking partners for licensing, research collaboration, or both.
