Effect of light intensity on current collection in thin-film solar cells
- National Renewable Energy Lab., Golden, CO (United States)
The authors have measured the current-voltage curves of thin-film solar cells using focused laser spots (30--500 {micro}m) using DC and modulated (AC) photocurrent techniques. The AC short-circuit current response (I{sub 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 reproducible spatial fluctuations in AC I{sub 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{sub SC} was largest in a-Si:H, intermediate in CdTe and CuInSe{sub 2}(CIS), barely noticeable in some Cu(Ga,In)Se{sub 2} (CIGS) cells and absent in silicon cells. The observations on CIGS and some CIS cells can be explained by internal series resistance, 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.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 302509
- Report Number(s):
- CONF-970953-; TRN: IM9904%%297
- Resource Relation:
- Conference: 26. IEEE photovoltaic specialists conference, Anaheim, CA (United States), 29 Sep - 3 Oct 1997; Other Information: PBD: 1997; Related Information: Is Part Of Conference record of the twenty sixth IEEE photovoltaic specialists conference -- 1997; PB: 1477 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
A 10% Cu(In,Ga)Se{sub 2} based photovoltaic structure formed by electrodeposition and subsequent thermal processing
Device physics of thin-film polycrystalline cells and modules. Annual subcontract report, December 6, 1994--December 5, 1995