Making photovoltaic cells affordable
Converting the endless radiation from the Sun into electricity has significant environmental and economic benefits. Solar or photovoltaic (PV) cell modules are used to facilitate this conversion and are made by depositing one or more thin layers of PV material on a substrate with varying thickness (a few nanometres to tens of micrometres). However, the elevated prices of current PV modules hamper their widespread use, necessitating the development of new cost-effective technologies. The key objective of the EU-funded project ‘Production process for industrial fabrication of low price amorphous-microcrystalline silicon solar cells’ (LPAMS) was to increase the efficiency of PV cells while making their production cheaper. To reach their goal, project partners focused on improving layer transparency, minimising optical losses, avoiding light-induced degradation and enlarging the effective absorption spectrum. The consortium optimised an industrial-scale transparent conducting oxide (TCO) deposition followed by layering of amorphous-, micro- or nanocrystalline silicon (Si) film onto glass substrate using the method of microwave chemical vapour deposition (MWPECVD). The innovation in the technology lied in the fact that the substrate could move through different deposition chambers for sequential multilayer deposition. Additionally, the LPAMS system was modular and could be easily extended for tandem or triple cell deposition. Overall, project partners succeeded in improving the layer quality and rate for the Si deposition and Si tandems fabrication. The most effective combination proved to be the nano- and amorphous-crystalline silicon tandems, exhibiting improved stability and expansion of the absorption spectrum. In addition, the process required a low number of workers thereby lowering the final price of solar cells produced in this way. Furthermore, since the tandem cells had larger efficiency on the same substrate and the same production costs, the price per unit power was lower. The LPAMS project produced a new generation of highly efficient PV modules with reduced manufacturing costs compared to conventional methods. Besides low-cost PV production, this method will prove beneficial for local development of innovative and clean technologies in Western Balkan Countries (WBCs).
