Improved equivalent circuit and analytical model for amorphous silicon solar cells and modules

• Published in: IEEE transactions on electron devices Vol. 45; no. 2; pp. 423 - 429
• Main Authors: Merten, J., Asensi, J.M., Voz, C., Shah, A.V., Platz, R., Andreu, J.
• Format: Journal Article
• Language: English
• Published: IEEE 01.02.1998
• Subjects: Amorphous materials; Amorphous semiconductors; Amorphous silicon; Amorphous silicon solar cells and modules; Analytical models; Current-voltage characteristics; Cèl.lules solars; Electron-hole recombination; Elemental semiconductors; Equivalent circuits; Hidrogen; Hydrogen; Lighting; Losses; P-i-n diodes; Photoconductivity; Photovoltaic cells; Physics; Semiconductor device models; Semiconductors; Semiconductors amorfs; Silicon; Silicones; Solar cells
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/16.658676

An improved equivalent circuit for hydrogenated amorphous silicon (a-Si:H) solar cells and modules is presented. It is based on the classic combination of a diode with an exponential current-voltage characteristic, of a photocurrent source plus a new term representing additional recombination losses in the i-layer of the device. This model/equivalent circuit matches the I(V) curves of a-Si:H cells over an illumination range of six orders of magnitude. The model clearly separates effects related to the technology of the device (series and parallel resistance) and effects related to the physics of the p-i-n junction (recombination losses). It also allows an effective /spl mu//spl tau/ product in the i-layer of the device to be determined, characterizing its state of degradation.