New PV conversion phenomena on very high efficiency silicon devices for small footprint cells (automotive)

摘要

Progress in PV conversion efficiency requires optoelectronic breakthroughs. Completing one-step PV conversion by additional new low-energy mechanisms is one of the most important challenges of modern photovoltaics. Si is a basic PV material which cannot be efficient enough in its bulk or thin-film form because of its indirect bandgap. One way has been indicated by multi-interface solar cell on single-crystal Si combining nanostructured Si materials and device improvements leading to a PV metamaterial conditioned simultaneously both electrically and mechanically by the built-in electrical and local stress fields. This allows a two membrane-like conversion cycle where a nanoscale Si-layered system plays a specific role due to an active interface and crystalline defects. We demonstrate a step-like collection efficiency curve proving new low-energy (0.3 eV) carrier generation and multiplication has been measured under solar intensities on dedicated test structures.