Effects of Light Intensity on Current Collection in Thin-Film Solar Cells

Effects of Light Intensity on Current Collection in Thin-Film Solar Cells

Research output: Contribution to conference › Paper

Abstract

We have measured the current-voltage curves of thin-film solar cells using focused laser spots (30 - 500 mm) using DC and modulated (AC) photocurrent techniques. The AC short-circuit current response (I SC ) and the AC fill factors (FF) decrease for small spot sizes corresponding to; several 100 sun light intensities. Laser line scans across the devices produced significant but reproduciblespatial fluctuations in AC I SC . These spatial variations depend on spot size and are reduced by scanning with lower light intensity. The reduction of AC FF and AC I SC was largest in a-Si:H, intermediate in CdTe and CuInSe 2 (CIS), barely noticeable in some Cu(Ga,In)Se 2 (CIGS) cells and absent in a silicon cells. The observations on CIGS and some CIS cells can be explained by internal seriesresistance, but field dependent collection and recombination effects must be invoked to explain results on most thin-film solar cell materials. Such field modification is not accounted for in standard exponential diode equation models.

Original language	American English
Number of pages	5
State	Published - 1997
Event	Twenty Sixth IEEE Photovoltaic Specialists Conference - Anaheim, California Duration: 29 Sep 1997 → 3 Oct 1997

Conference

Conference	Twenty Sixth IEEE Photovoltaic Specialists Conference
City	Anaheim, California
Period	29/09/97 → 3/10/97

Bibliographical note

Available electronically only

NREL Publication Number

NREL/CP-520-22921

Access to Document

https://www.nrel.gov/docs/legosti/fy97/22921.pdf

Cite this

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title = "Effects of Light Intensity on Current Collection in Thin-Film Solar Cells",

abstract = "We have measured the current-voltage curves of thin-film solar cells using focused laser spots (30 - 500 mm) using DC and modulated (AC) photocurrent techniques. The AC short-circuit current response (I SC ) and the AC fill factors (FF) decrease for small spot sizes corresponding to; several 100 sun light intensities. Laser line scans across the devices produced significant but reproduciblespatial fluctuations in AC I SC . These spatial variations depend on spot size and are reduced by scanning with lower light intensity. The reduction of AC FF and AC I SC was largest in a-Si:H, intermediate in CdTe and CuInSe 2 (CIS), barely noticeable in some Cu(Ga,In)Se 2 (CIGS) cells and absent in a silicon cells. The observations on CIGS and some CIS cells can be explained by internal seriesresistance, but field dependent collection and recombination effects must be invoked to explain results on most thin-film solar cell materials. Such field modification is not accounted for in standard exponential diode equation models.",

author = "NREL",

note = "Available electronically only; Twenty Sixth IEEE Photovoltaic Specialists Conference ; Conference date: 29-09-1997 Through 03-10-1997",

year = "1997",

language = "American English",

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TY - CONF

T1 - Effects of Light Intensity on Current Collection in Thin-Film Solar Cells

AU - NREL, null

N1 - Available electronically only

PY - 1997

Y1 - 1997

N2 - We have measured the current-voltage curves of thin-film solar cells using focused laser spots (30 - 500 mm) using DC and modulated (AC) photocurrent techniques. The AC short-circuit current response (I SC ) and the AC fill factors (FF) decrease for small spot sizes corresponding to; several 100 sun light intensities. Laser line scans across the devices produced significant but reproduciblespatial fluctuations in AC I SC . These spatial variations depend on spot size and are reduced by scanning with lower light intensity. The reduction of AC FF and AC I SC was largest in a-Si:H, intermediate in CdTe and CuInSe 2 (CIS), barely noticeable in some Cu(Ga,In)Se 2 (CIGS) cells and absent in a silicon cells. The observations on CIGS and some CIS cells can be explained by internal seriesresistance, but field dependent collection and recombination effects must be invoked to explain results on most thin-film solar cell materials. Such field modification is not accounted for in standard exponential diode equation models.

AB - We have measured the current-voltage curves of thin-film solar cells using focused laser spots (30 - 500 mm) using DC and modulated (AC) photocurrent techniques. The AC short-circuit current response (I SC ) and the AC fill factors (FF) decrease for small spot sizes corresponding to; several 100 sun light intensities. Laser line scans across the devices produced significant but reproduciblespatial fluctuations in AC I SC . These spatial variations depend on spot size and are reduced by scanning with lower light intensity. The reduction of AC FF and AC I SC was largest in a-Si:H, intermediate in CdTe and CuInSe 2 (CIS), barely noticeable in some Cu(Ga,In)Se 2 (CIGS) cells and absent in a silicon cells. The observations on CIGS and some CIS cells can be explained by internal seriesresistance, but field dependent collection and recombination effects must be invoked to explain results on most thin-film solar cell materials. Such field modification is not accounted for in standard exponential diode equation models.

M3 - Paper

T2 - Twenty Sixth IEEE Photovoltaic Specialists Conference

Y2 - 29 September 1997 through 3 October 1997

ER -

Effects of Light Intensity on Current Collection in Thin-Film Solar Cells

Abstract

Conference

Bibliographical note

NREL Publication Number

Access to Document

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Cite this