Optimized emitter contacting on multicrystalline silicon thin film solar cells

Gawlik, Annett; Höger, I.; Bergmann, J.; Plentz, Jonathan; Schmidt, Thomas; Falk, F.; Andrä, G.

doi:10.1002/pssr.201510186

Cited by 12 publications

(11 citation statements)

References 16 publications

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“…Generally, LPC‐Si cells have been realized with homojunctions or with a‐Si/c‐Si heterojunctions (SHJ). First LPC‐Si‐based solar cells implemented homojunctions and resulted in good cell results (section 5). At Helmholtz‐Zentrum Berlin, we focus on heterojunctions consisting of thin intrinsic and doped amorphous silicon emitters and back‐surface fields.…”

Section: Fabrication Of Liquid‐phase Crystallized Silicon‐based Solarmentioning

confidence: 99%

Crystalline silicon on glass—interface passivation and absorber material quality

Gabriel

Frijnts

Preissler

et al. 2015

Progress in Photovoltaics

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Thin crystalline silicon solar cells prepared directly on glass substrates by means of liquid-phase crystallization of the absorber utilize only a small fraction of the silicon material used by standard wafer-based silicon solar cells. The material consists of large crystal grains of up to square centimeter area and results in solar cells with open-circuit voltages of 650 mV, which is comparable with results achieved with multi-crystalline silicon wafers. We give a brief status update and present new results on the electronic interface and bulk properties. The interrelation between surface passivation and additional hydrogen plasma passivation is investigated for p-type and n-type absorbers with different doping concentrations. Internal quantum efficiency measurements from both sides on bifacial solar cells are used to extract the bulk-diffusion length and surface-recombination velocity. Finally, we compare various types of solar cell devices based on 10 μm thin crystalline silicon, where conversion efficiencies of 11-12% were achieved with p-type and n-type liquid-phase crystallized absorbers on glass.

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Section: Fabrication Of Liquid‐phase Crystallized Silicon‐based Solarmentioning

confidence: 99%

Crystalline silicon on glass—interface passivation and absorber material quality

Gabriel

Frijnts

Preissler

et al. 2015

Progress in Photovoltaics

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“…Liquid‐phase crystallized silicon on glass (LPCSG) via line‐focus laser beam irradiation is a promising way to fabricate high‐quality polycrystalline silicon (Si) solar cell absorbers. Solar cell efficiency above 12% has been achieved in about 10 μm thick LPCSG absorbers with short circuit current densities ( I sc) of nearly 30 mA cm −2 by introducing light trapping (LT) structures at the front and the backside of the solar cell, where the front side is the illuminated glass side of the solar cell (so‐called superstrate configuration) . The impact of the conventional pyramidal LT structures on light absorption has been studied in detail .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of light trapping structures for liquid-phase crystallized silicon on glass (LPCSG)

Vetter

Jia

Sanei

et al. 2017

Phys. Status Solidi A

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Liquid‐phase crystallized silicon on glass (LPCSG) presents a promising material to fabricate high quality silicon thin films, e.g., for solar cells and modules. Using continuous wave line focus laser irradiation at 808 nm, about 10 μm thick microcrystalline silicon layers are fabricated by liquid‐phase crystallization of amorphous or nanocrystalline silicon layers deposited by electron beam evaporation on Borofloat 33 glass. To achieve high solar cell efficiencies with such thin silicon layers, effective light trapping structures at the silicon surface are needed to enhance the light absorption and thereby the current in the solar cell. At the same time, these surface structures must provide low surface recombination velocity to maintain high open circuit voltage (Voc). Light trapping structures in LPCSG absorber prepared by conventional KOH texturing and by nanowire structuring of the solar cell backside are investigated. The impact of structures on short circuit current density (Isc) is determined from optical measurements. As a new approach, effective carrier lifetime is measured in LPCSG absorbers using the quasi steady‐state photoconductance method to determine the impact of structuring on surface recombination and implied Voc of solar cell precursors. Carrier lifetimes in the range of 300–400 ns are measured indicating a carrier diffusion length of more than 20 μm, which is 2–3 times larger than the layer thickness. It is found that a slight pyramidal surface texture by KOH solution provides a high level of light trapping increasing Isc by 17–18% and maintaining high Voc (>600 mV). The potential for current enhancement of nanowire structuring is higher (≈20%), but further optimization of nanowire dimensions and of surface cleaning of nanowire structures is needed to overcome higher surface recombination and the resulting Voc losses.

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“…As an alternative to wafer‐based c‐Si photovoltaic devices, liquid phase crystallized (LPC) thin‐film silicon on glass technology has been proposed at a laboratory scale. In this technology, amorphous silicon is deposited on glass and subsequently recrystallized by a line‐focused laser beam or an electron beam . The resulting multicrystalline thin‐film silicon is ready for the definition of emitter and base contacts in an interdigitated back‐contacted (IBC) structure at the rear surface using a low‐temperature approach.…”

Section: Introductionmentioning

confidence: 99%

Multicrystalline Silicon Thin‐Film Solar Cells Based on Vanadium Oxide Heterojunction and Laser‐Doped Contacts

Martı́n

López

Plentz

et al. 2019

Physica Status Solidi (a)

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Liquid phase crystallized (LPC) silicon thin films on glass substrates are a feasible alternative to conventional crystalline silicon (c‐Si) wafers for solar cells. Due to substrate limitation, a low‐temperature technology is needed for solar cell fabrication. While silicon heterojunction is typically used, herein, the combination of vanadium oxide/c‐Si heterojunction as emitter and base contacts defined by IR laser processing of phosphorus‐doped amorphous silicon carbide stacks is explored. LPC solar cells are fabricated using such technologies to identify their issues and advantages with a promising performance of an active‐area efficiency of 5.6%. Apart from the absence of light‐trapping techniques, the relatively low efficiency obtained is attributed to a low lifetime in the LPC silicon bulk. These poor material properties imply a short diffusion length that makes it that only photogenerated carriers in the emitter regions can be collected. Consequently, future devices should show narrower base contact regions, suggesting a shorter‐wavelength laser, combined with longer LPC substrate lifetimes.

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Optimized emitter contacting on multicrystalline silicon thin film solar cells

Cited by 12 publications

References 16 publications

Crystalline silicon on glass—interface passivation and absorber material quality

Crystalline silicon on glass—interface passivation and absorber material quality

Evaluation of light trapping structures for liquid-phase crystallized silicon on glass (LPCSG)

Multicrystalline Silicon Thin‐Film Solar Cells Based on Vanadium Oxide Heterojunction and Laser‐Doped Contacts

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