100% internal quantum efficiency in polychiral single-walled carbon nanotube bulk heterojunction/silicon solar cells. (April 2017)

• Record Type: Journal Article
• Authors: De Nicola, Francesco; Salvato, Matteo; Cirillo, Carla; Crivellari, Michele; Boscardin, Maurizio; Passacantando, Maurizio; Nardone, Michele; De Matteis, Fabio; Motta, Nunzio; De Crescenzi, Maurizio; Castrucci, Paola
• Is Part Of: Carbon. Volume 114(2017)
• Page Start: 402
• Page End: 410
• Publication Date: 2017-04
• Subjects: Third generation solar cell -- Photovoltaic -- Bulk heterojunction -- Single-walled carbon nanotube -- Internal quantum efficiency -- Silicon -- Air-stable encapsulation -- Anti-reflective coating -- Hydrophobic film; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2016.12.050
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Bulk heterojunction films made of polychiral single-walled carbon nanotubes (SWCNTs) form efficient heterojunction solar cells with n-type crystalline silicon (n-Si), due to their superior electronic, optical, and electrical properties. The films are multi-functional, since their hierarchical surface morphology provides a biomimetical anti-reflective, air-stable, and hydrophobic encapsulation for Si. Also, the films have a large effective area conferring them high optical absorption, which actively contribute to the solar energy harvesting together with Si. Here, we report photovoltaic devices with photoconversion efficiency up to 12% and a record 100% internal quantum efficiency (IQE). Such unprecedented IQE value is truly remarkable and indicates that every absorbed photon from the device, at some wavelengths, generates a pair of separated charge carriers, which are collected at the electrodes. The SWCNT/Si devices favor high and broadband carrier photogeneration; charge dissociation of ultra-fast hot excitons; transport of electrons through n-Si and high-mobility holes through the SWCNT percolative network. Moreover, by varying the film thickness, it is possible to tailor the physical properties of such a two-dimensional interacting system, therefore the overall device features. These results not only pave the way for low-cost, high-efficient, and broadband photovoltaics, but also are promising for the development of generic SWCNT-based optoelectronic applications. Graphical abstract: