Articolo in rivista, 2015, ENG, 10.1088/0022-3727/48/36/365101

Directly patterned TiO<inf>2</inf> nanostructures for efficient light harvesting in thin film solar cells

Ram, Sanjay K.; Rizzoli, Rita; Desta, Derese; Jeppesen, Bjarke R.; Bellettato, Michele; Samatov, Ivan; Tsao, Yao Chung; Johannsen, Sabrina R.; Neuvonen, Pekka T.; Pedersen, Thomas Garm; Pereira, Rui N.; Pereira, Rui N.; Pedersen, Kjeld; Balling, Peter; Larsen, Arne Nylandsted

Aarhus Universitet; Consiglio Nazionale delle Ricerche; Universidade de Aveiro; Aalborg Universitet; Walter Schottky Institute

A novel, scalable, and low-cost strategy for fabricating sub-wavelength scale hierarchical nanostructures by direct patterning of TiO<inf>2</inf> nanoparticles on glass substrates is reported. Two nanostructural designs of light-trapping back-surface reflectors (BSR) have been fabricated for increasing the photon-harvesting properties of thin-film solar cells: a quasi-periodic nano-crater design and a random nano-bump design. The efficient light-scattering properties of the nano-crater design over a broad wavelength range are demonstrated by the measured haze factor being larger than 40% at wavelengths (~700 nm) near the band edge of amorphous silicon (a-Si:H). The a-Si:H-based n-i-p solar cell fabricated with an only ~200 nm thick absorber layer on the nano-crater BSR shows a short-circuit current density (J <inf>sc</inf>) of ~16.1 mA cm<sup>-2</sup> representing a 28% enhancement compared to the cell deposited on a non-textured flat substrate. Measurements of the external quantum efficiency of the cell fabricated on the quasi-periodic nano-crater surface at long wavelengths, ? > 700 nm, demonstrate an increase of a factor of 5 relative to that of a flat reference solar cell. The theoretical modeling results of optical absorption corroborate well with the experimental findings and are used to identify the volumes of strong optical absorption in the a-Si:H active layer of the textured BSR devices.

Journal of physics. D, Applied physics (Print) 48 (36), pp. 365101–365111

Keywords

light trapping, nanomolding, nanoparticles, photovoltaic devices, silicon, solar cells, thin films

CNR authors

Bellettato Michele, Rizzoli Rita

CNR institutes

IMM – Istituto per la microelettronica e microsistemi

ID: 348851

Year: 2015

Type: Articolo in rivista

Creation: 2016-03-01 12:43:32.000

Last update: 2021-03-11 17:09:37.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:348851

DOI: 10.1088/0022-3727/48/36/365101

Scopus: 2-s2.0-84940121382