Printing Hybrid, Interdigitated Back-Contact Solar Cells

TL;DR

This paper presents a new method for fabricating interdigitated back-contact solar cells using only inkjet printing, achieving good performance without vacuum processes.

Contribution

The novel contribution is the complete fabrication of IBC solar cells using a single inkjet printer, eliminating vacuum deposition and diffusion.

Findings

PEDOT:PSS, TiO2, and metal lines were successfully printed on textured silicon using inkjet printing.

Adding co-solvent and surface passivation improved Jsc, fill factor, and efficiency despite a thicker PEDOT:PSS layer.

Anti-reflective coating and improved metal contact ink are needed to further enhance device performance.

Abstract

Interdigitated back-contact solar cells were fabricated entirely with inkjet printing. poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), TiO2, and metal lines were printed on a textured silicon substrate with only one inkjet printer. No vacuum deposition or diffusion of a back surface field is needed for the printed IBC solar cell. Adding co-solvent to the PEDOT:PSS and passivation of the Si surface significantly reduced the losses and enhanced the short-circuit current, Jsc, and, as a result, improved the fill factor and efficiency of the devices. The thickness of the PEDOT:PSS layer is approximately half a micrometer measured by profilometer, which is thicker than the optimal range typically reported; there is still a best short-circuit current, Jsc, of 19.2 mA/cm2. To further improve the performance of the devices, an anti-reflective coating on the front side is required. Also, an improved metal contact ink is needed to improve the contact resistance between the PEDOT:PSS layer and the metal contact. The initial performance of all printed cells are compared to conventionally fabricated devices.

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