Effect of wide band-gap TCO properties on the bifacial CZTS thin-films solar cells performances

• Published in: Optik (Stuttgart) Vol. 144; pp. 370 - 377
• Main Authors: Bouchama, Idris, Ali-Saoucha, Salim
• Format: Journal Article
• Language: English
• Published: Elsevier GmbH 01.09.2017
• Subjects: AMPS-1D; Bifacial solar cells; Cu2ZnSnS4; Thin films; Thin films; Cu2ZnSnS4; Bifacial solar cells; AMPS-1D
• ISSN: 0030-4026; 1618-1336
• DOI: 10.1016/j.ijleo.2017.07.009

In this work, one-dimensional device simulator AMPS-1D was employed to study the electrical and optical properties of bifacial ZnO:Al/CdS/Cu2ZnSnS4 (CZTS)/TCO/SLG thin film solar cells. The impact of barrier height in the CZTS/TCO interface has been investigated for front and back side illuminations. The combination of the optical transparency and the electrical properties for the TCO back contact layer are capable of yielding high efficiency. The presence of barriers in the CZTS/TCO back-side interface of the structure can significantly affect the cell performance by limit the carriers current flow. The optimum CZTS absorber layer thickness used in the simulation has been calculated. The best energy conversion efficiency has been calculated in the case of front and back side illuminations. In the case of front side illumination, an efficiency of 15.8% (withVoc≈0.93V,Jsc≈18.7mA/cm2, FF≈0.77 and QE≈82.5% at 570nm) have been obtained with a barrier height close to 0.4eV. In the case of back side illumination, we notice a low performances. For 0.4eV barrier height, we obtain 1.8% (withVoc≈0.95V,Jsc≈2.6mA/cm2, FF≈0.74 and QE≈20.6% at 820nm). Without barrier height we obtain a maximum of efficiency (η≈4%) in the case of back side illumination. All these simulation results give some important indication to lead a higher efficiency of bifacial CdS/CZTS/TCO structure for feasible fabrication.