Drastic performance enhancement by using a WOx buffer before ZnO back reflector in amorphous silicon solar cells fabricated at 121 °C

AbstractPhotonic crystal back reflectors offer enhanced optical absorption in thin-film solar cells, without undesirable losses. Rigorous simulations of photonic crystal back reflectors predicted maximized light absorption in amorphous silicon solar cells for a pitch of 700-800 nm. Simulations also predict that for typical 250 nm i-layer cells, the periodic photonic crystal back reflector can improve absorption over the ideal randomly roughened back reflector (or the ‘4n2classical limit') at wavelengths near the band edge. The PC back reflector provides even higher enhancement than roughened back reflectors for cells with even thinner i-layers. Using these simulated designs, we fabricated metallic photonic crystal back reflectors with different etch depths and i-layer thicknesses. The photonic crystals had a pitch of 760 nm and triangular lattice symmetry. The average light absorption increased with the PC back reflectors, but the greatest improvement (7-8%) in short circuit current was found for thinner i-layers. We have studied the dependence of cell performance on the etch depth of the photonic crystal. The photonic crystal back reflector strongly diffracts light and increases optical path lengths of solar photons.

Download Full-text

Parasitic loss mitigation and photocurrent enhancement in amorphous silicon solar cells by using phosphorous-doped fluorinated µc-SiO:H back reflector

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-018-9193-y ◽

2018 ◽

Vol 29 (13) ◽

pp. 11104-11116 ◽

Cited By ~ 2

Author(s):

G. Ahmad ◽

S. Mandal ◽

A. K. Barua ◽

T. K. Bhattacharyya ◽

J. N. Roy

Keyword(s):

Solar Cells ◽

Amorphous Silicon ◽

Silicon Solar Cells ◽

Loss Mitigation ◽

Back Reflector

Download Full-text

Novel approaches of light management in thin-film silicon solar cells

MRS Proceedings ◽

10.1557/proc-0910-a25-01 ◽

2006 ◽

Vol 910 ◽

Cited By ~ 12

Author(s):

Janez Krc ◽

M. Zeman ◽

A. Campa ◽

F. Smole ◽

M. Topic

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Photonic Crystal ◽

Amorphous Silicon ◽

Wavelength Region ◽

Silicon Solar Cells ◽

Novel Approaches ◽

Back Reflector ◽

High Reflectance

AbstractIn order to improve light trapping in thin-film silicon solar cells two novel approaches are investigated in this article: angle-selective management of light scattering inside the solar cell and wavelength-selective manipulation of high reflectance or transmittance of light. Diffraction gratings are analyzed as a representative of the first approach. Haze and angular distribution function of scattered (diffracted) light in reflection are measured for aluminum-based rectangular periodic gratings with different period and height of the rectangles. High haze values in specific wavelength region and scattering angles of the investigated gratings measured in air and water agree very well with the theoretical predictions. Considering the actual optical situation in microcrystalline silicon solar cells, optimal period and height of the rectangular gratings applied as a back reflector are calculated for obtaining the total reflection at the front interfaces. In the frame of the second approach, photonic-crystal-like structures are introduced. By means of optical simulations photonic-crystal-like structures are investigated for two possible applications: an intermediate reflector in a micromorph silicon solar cell with wavelength-selective reflectivity and a dielectric back reflector with a high reflectance in the long-wavelength region. The photonic crystal structure consisting of sequences of n-doped amorphous silicon and ZnO layers is designed for the efficient intermediate reflector. For the back reflector with a high reflectance the structures with intrinsic amorphous silicon, SiO2, MgF2 and TiO2 are proposed.

Download Full-text

Enhanced Absorption in Amorphous Silicon Solar Cells Using Plasmonic and Photonic Crystals – Measurement and Simulation

MRS Proceedings ◽

10.1557/proc-1248-d05-03 ◽

2010 ◽

Vol 1248 ◽

Author(s):

Benjamin Curtin ◽

Rana Biswas ◽

Vikram Dalal

Keyword(s):

Thin Film ◽

Solar Cells ◽

Photonic Crystal ◽

Photonic Crystals ◽

Amorphous Silicon ◽

Near Infrared ◽

Silicon Solar Cells ◽

Back Reflectors ◽

Back Reflector ◽

Hole Arrays

AbstractWe develop experimentally and theoretically plasmonic and photonic crystals for enhancing thin film silicon solar cells. Thin film amorphous silicon (a-Si:H) solar cells suffer from decreased absorption of red and near-infrared photons, where the photon absorption length is large. Simulations predict maximal light absorption for a pitch of 700-800 nm for photonic crystal hole arrays in silver or ZnO/Ag back reflectors, with absorption increases of ~12%. The photonic crystal improves over the ideal randomly roughened back reflector (or the ‘4n2limit’) at wavelengths near the band edge. We fabricated metallic photonic crystal back-reflectors using photolithography and reactive-ion etching. We conformally deposited a-Si:H solar cells on triangular lattice hole arrays of pitch 760 nm on silver back-reflectors. Electron microscopy demonstrates excellent long range periodicity and conformal a-Si:H growth. The measured quantum efficiency increases by 7-8 %, relative to a flat reflector reference device, with enhancement factors exceeding 6 at near-infrared wavelengths. The photonic crystal back reflector strongly diffracts light and increases optical path lengths of solar photons.

Download Full-text

Hybrid Dielectric-Metallic Back Reflector for Amorphous Silicon Solar Cells

Energies ◽

10.3390/en3121914 ◽

2010 ◽

Vol 3 (12) ◽

pp. 1914-1933 ◽

Cited By ~ 10

Author(s):

James G. Mutitu ◽

Shouyuan Shi ◽

Allen Barnett ◽

Dennis W. Prather

Keyword(s):

Solar Cells ◽

Amorphous Silicon ◽

Silicon Solar Cells ◽

Back Reflector

Download Full-text

Photonic Crystal Back Reflector in Thin-film Silicon Solar Cells

MRS Proceedings ◽

10.1557/proc-1153-a03-05 ◽

2009 ◽

Vol 1153 ◽

Cited By ~ 7

Author(s):

Olindo Isabella ◽

Benjamin Lipovšek ◽

Janez Krč ◽

Miro Zeman

Keyword(s):

Solar Cells ◽

Photonic Crystals ◽

Amorphous Silicon ◽

Wavelength Region ◽

Silicon Solar Cells ◽

Angle Of Incidence ◽

Back Reflector ◽

Ag Reflector ◽

Nitride Layers ◽

Broad Region

AbstractOne-dimensional photonic crystals having desired broad region of high reflectance (R) were fabricated by alternating the deposition of amorphous silicon and amorphous silicon nitride layers. The effect of the deposition temperature and angle of incidence on the optical properties of photonic crystals deposited on glass substrate was determined and an excellent matching was found with the simulated results. The broad region of high R of photonic crystals deposited on flat and textured ZnO:Al substrates decreases when compared to the R of photonic crystals de-posited on glass. The performance of amorphous silicon solar cells with 1-D photonic crystals integrated as the back reflector was evaluated. The external quantum efficiency measurement demonstrated that the solar cells with the photonic crystals back reflector had an enhanced re-sponse in the long wavelength region (above 550 nm) compared to the cells with the Ag reflector.

Download Full-text