Stable Organic Passivated Carbon Nanotube–Silicon Solar Cells with an Efficiency of 22%

The organic passivated carbon nanotube (CNT)/silicon (Si) solar cell is a new type of low-cost, high-efficiency solar cell, with challenges concerning the stability of the organic layer used for passivation. In this work, the stability of the organic layer is studied with respect to the internal and external (humidity) water content and additionally long-term stability for low moisture environments. It is found that the organic passivated CNT/Si complex interface is not stable, despite both the organic passivation layer and CNTs being stable on their own and is due to the CNTs providing an additional path for water molecules to the interface. With the use of a simple encapsulation, a record power conversion efficiency of 22% is achieved and a stable photovoltaic performance is demonstrated. This work provides a new direction for the development of high-performance/low-cost photovoltaics in the future and will stimulate the use of nanotubes materials for solar cells applications.