Scribe Width Optimization of Absorber Laser Ablation for Thin-film Silicon Solar Modules

Abstract

Ultrashort pulse lasers have been established as precise and universal tools for the micromachining of solid materials (cutting, texturing …). For these applications the quality of the cutting cross-section is important. The use of a Gaussian beam profile and linear polarization leads to tapered cutting sidewalls. It is possible to change the polarization orientation in order to machine a material for obtaining straight and vertical sidewalls. For this purpose a specific polarization converter was used. The transformation of the polarization distribution from linear to radial and azimuthal is done by a subwavelength, binary grating creating a π phase shift between the TE and TM transmitted waves. In this paper we report on investigations on the influence of laser polarization (radial, azimuthal, circular, linear) on the ablation characteristics of molybdenum and PZT using an Yb doped crystal laser (500 fs) and compare these results with previously published results.

Laser-Patterning Engineering for Perovskite Solar Modules With 95% Aperture Ratio

“…These can be resumed in a parameter, named Total Loss (TL). [53,54] The TL can be expressed as a function of AA width (WA) and DA width (WD), for a fixed value of P1, P3, and SA widths and a defined transfer length ( ) in the P2 process. The TL is composed by three main parts: geometrical losses due to the realization of DA; Ohmic losses over the AA, due to the non--negligible FTO sheet resistance; Ohmic losses over the interconnection area realized with the P2 step.…”

“…The TL is composed by three main parts: geometrical losses due to the realization of DA; Ohmic losses over the AA, due to the non--negligible FTO sheet resistance; Ohmic losses over the interconnection area realized with the P2 step. By extending the procedure in [54] and according to well-known mathematical models, [53,55,56] we can express the TL in terms of module parameters:…”

Impact of scribe width reduction on the back-contact insulation process for the series connection of thin-film silicon solar cells

“…Previous investigations on the P2 ablation behavior showed a difference in the squared crater diameter D 2 between processing of a-Si:H and tandem solar cells (shift in the y-axis) [15]. For P3 processing with 60 and 20 lm, the Liu-Plots show almost no difference in crater diameter between the two absorber types for the same incident laser peak fluence.…”

“…Our previous works on this topic found a strong influence of the scribe width on P1 and P2 [14,15]. The present work extends the research on the back-contact insulation process P3 for the integrated series connection of thin-film silicon solar cells in superstrate configuration [16].…”

“…For both, a-Si:H and tandem solar cells, micro-explosion is most likely the driving ablation mechanism [15]. Thus, the threshold fluence and the onset peak fluence are influenced by mechanical properties of the materials and therefore also by the processing beam radius.…”