Directly patterned TiO2 nanostructures for efficient light harvesting in thin film solar cells

作者：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; Pedersen Kjeld; Balling Peter; Larsen Arne Nylandsted

来源：Journal of Physics D: Applied Physics , 2015, 48(36): 365101.

DOI：10.1088/0022-3727/48/36/365101

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

A novel, scalable, and low-cost strategy for fabricating sub-wavelength scale hierarchical nanostructures by direct patterning of TiO2 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 (similar to 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 similar to 200 nm thick absorber layer on the nano-crater BSR shows a short-circuit current density (J(sc)) of similar to 16.1 mA cm(-2) 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, lambda > 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.

• 出版日期2015-9-16