Geometry-driven carrier extraction enhancement in photovoltaic cells based on arrays of subwavelength light funnels

Prajapati, A. K.; Shalev, Gil

doi:10.1039/c9na00599d

Cited by 10 publications

(6 citation statements)

References 58 publications

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“…[ 17–19 ] Also, PV cells based on LF arrays were reported to provide enhanced PV performance due to inherent inverted configuration. [ 20,21 ] Recently, it was suggested that the mechanism for the superior absorption in LF arrays is inherently distinct from that of NP arrays; proximity effects in compact LF arrays result in an elevated excitation of the LFs, as opposed to NP arrays in which a reduction in the excitation accompanies the densification of the arrays, as discussed earlier. [ 12 ] Consider, for example, illumination of an isolated LF, in the shape of inverted cone, from an infinitely long cylindrical glass rod with the HE 11 waveguide mode.…”

Section: Introductionmentioning

confidence: 99%

Near‐Field Optical Excitations in Silicon Subwavelength Light Funnel Arrays for Broadband Absorption of the Solar Radiation

et al. 2021

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Broadband absorption is pivotal for the realization of green energy based on solar energy. Decoration of photovoltaic cells with arrays of subwavelength formations provides an efficient means for broadband absorption in thin films. Surface arrays of silicon light funnels (LFs) have been suggested as a promising platform to produce broadband absorption that is considerably superior to other subwavelength arrays such as the well‐known nanopillar (NP) arrays. The current study explores the underlying mechanism of broadband absorption in LF arrays. To this end, the optical near‐field of LF and NP arrays is experimentally probed using a near‐field scanning optical microscopy. It is shown that in LF arrays the near‐field increases as the array period decreases in contrast with NP arrays in which the near‐field decreases with decreasing array period. Also, the experimental near‐field of the arrays follows the numerically calculated absorption cross section of the array‐nested NPs/LFs. Therefore, the origin to the broadband absorption in compact LF arrays is due to field overlap of adjacent LFs which increases the absorption cross section of the individual LFs composing the array. This absorption cross‐sectional enhancement coupled with a higher filling ratio in compact arrays produces broadband absorption that is significantly greater than that of NP arrays.

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Section: Introductionmentioning

confidence: 99%

Near‐Field Optical Excitations in Silicon Subwavelength Light Funnel Arrays for Broadband Absorption of the Solar Radiation

et al. 2021

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“…[ 20–25 ] It was also suggested that the unique inverted shape of the LFs results in a contact‐selectivity enhancement, which promotes efficient carrier extraction and additional contribution to the already high photocurrents. [ 26 ] In a recent publication, we showed that the absorption mechanism in LF arrays is fundamentally different from NP arrays; proximity effects in dense LF arrays induce higher excitation levels inside the individual LFs in contrast with the NPs where a decrease in the excitation level is recorded, as discussed earlier. [ 27 ] This unique absorption mechanism in dense LF arrays is the key for the possible enhancement of photovoltage that is concurrent with the photocurrent enhancement.…”

Section: Introductionmentioning

confidence: 77%

Photovoltage Management Based on Enhanced Excitation Levels in Surface Arrays of Subwavelength Silicon Formations

Prajapati

Shalev

2020

Solar RRL

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Surface arrangements of subwavelength formations are extensively discussed in the context of photocurrent enhancement for photovoltaic (PV) applications. Recently, the potential contribution of such arrangements toward photovoltage augmentation is suggested. This study numerically demonstrates the potential for photovoltage management based on arrays composed of inverted silicon cones, referred to as light funnel (LF) arrays. The transition from an optimized nanopillar (NP) array into an LF array is examined. It is shown that a decrease in NP bottom diameter (Db) is accompanied by an increase in open‐circuit voltage (Voc). The highest photovoltage enhancement is recorded for the smallest considered Db = 50 nm with a Voc increase of 75 mV and reflects a 22% Voc enhancement compared with the NP Voc. It is shown that this Voc increase is due to 250% increase in the excitation level, and that the spatially resolved excitation level of the array‐nested LFs is more than two orders of magnitude higher than the highest spatially resolved excitation level in the array‐nested NPs. Finally, it is shown that the suggested photovoltage management entails almost a factor of 2 increase in the nominal power conversion efficiency upon the transition from an NP PV cell into LF PV cell.

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“…Carrier collection from photovoltaic (PV) cells based on arrays of subwavelength structures was previously reported. [11,12,37,[56][57][58][59][60] Carrier collection from LF arrays [61][62][63][64] and DSSS arrays [48] was numerically described previously using axial junction configuration with a shallow degenerated n-type emitter at the top of the arrays and a p-type absorber. The dependency on array geometry (LF D b values), surface recombination, and absorber doping concentrations was considered, and it was shown how the enhanced broadband absorption is translated into elevated values of short-circuit current ( J sc ) as compared with NP arrays.…”

Section: Resultsmentioning

confidence: 99%

Broadband and Omnidirectional Antireflection Surfaces Based on Deep Subwavelength Features for Harvesting of the Solar Energy

et al. 2021

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Geometry-driven carrier extraction enhancement in photovoltaic cells based on arrays of subwavelength light funnels

Abstract: Texturing the front surface of thin film photovoltaic cells with ordered or disordered arrangements of subwavelength structures is beneficial in terms of efficient light harvesting as well as efficient carrier extraction.

Cited by 10 publications

References 58 publications

Near‐Field Optical Excitations in Silicon Subwavelength Light Funnel Arrays for Broadband Absorption of the Solar Radiation

Near‐Field Optical Excitations in Silicon Subwavelength Light Funnel Arrays for Broadband Absorption of the Solar Radiation

Photovoltage Management Based on Enhanced Excitation Levels in Surface Arrays of Subwavelength Silicon Formations

Broadband and Omnidirectional Antireflection Surfaces Based on Deep Subwavelength Features for Harvesting of the Solar Energy

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