Laser structuring of thin-film solar cells on polymers

Abstract

Abstract.A permanent growth of the thin-film electronics market stimulates the development of versatile technologies for patterning thin-film materials on flexible substrates. High repetition rate lasers with a short pulse duration offer new possibilities for high efficiency structuring of conducting, semi-conducting and isolating films. Lasers with the picosecond pulse duration were applied in structuring the complex multilayered Cu(InGa)Se 2 (CIGS) solar cells deposited on the polyimide substrate. The wavelength of laser radiation was adjusted depending on optical properties both of the film and the substrate. A narrow processing window of laser fluence and pulse overlap was estimated with both 1064 nm and 355 nm irradiation to remove the molybdenum backcontact off the substrate. The selective removal of ITO, ZnO and CIGS layers was achieved with 355 nm irradiation in the multilayer structure of CIGS without significant damage to the underneath layers. Use of the flat-top laser beam profile should prevent inhomogeneity in ablation. The EDS analysis did not show residues of molybdenum projected onto the walls of ablated channel due to melt extrusion. Processing with picosecond lasers should not cause degradation of photo-electrical properties of the solar cells but verification is required.

Scribing of a-Si thin-film solar cells with picosecond laser

“…The picosecond laser was chosen for the experiments because the short pulse duration might prevent thermal damage and degradation of materials, enabling a selective high quality ablation of the films. More details on the experimental setup are in [8]. The laser spot overlap along a scanning line was controlled by the translation speed at a constant pulse repetition rate.…”

“…Lasers with a shorter, picosecond pulse duration were successfully applied in scribing the monolayer thin film structures deposited on glass [5,6] and polymer substrates [7]. The technique was also applied in scribing films for the CIGS solar cells [8]. The experiments revealed potential of picosecond lasers in selective structuring of thin films when the wavelength of laser radiation was adjusted depending on optical properties both of the film and the substrate.…”

Picosecond Soliton Pulse Generation Using a PANDA System for Solar Cells Fabrication

“…2 3 The wavelength of the input laser pulse can be selected in proper ways, which is important to carry on the power coupling into the interlayer interface. 4 Welldesigned thin-films are of high importance in modern electronics for flat sheet displays, photovoltaics, flexible and organic electronics. 5 Adaptable technologies are necessary for patterning thin-film materials on rigid and flexible substrates.…”

Precise microstructuring of indium-tin oxide thin films on glass by selective femtosecond laser ablation

“…To comply with the need of precise microstructures like, for instance, groove widths below 10 μm providing perfect electrical isolation, ultrashort pulses have to be used in order to avoid any thermal damage or contamination in the ablated region. Previous empirical studies using pico-or femtosecond pulses at several wavelengths from the near infrared to ultraviolet spectral range showed that a fairly "clean" ablation of TCOs or photovoltaic absorber thin films is possible by irradiating successive pulses with considerable spatial overlap from the TCO side [1][2][3][4][5][6][7].…”