Laser processing of solar cells

Abstract

Laser processing has a long history in the manufacturing of solar cells since most thin-film photovoltaic modules have been manufactured using laser scribing for more than thirty years. Lasers have also been used by many solar cell manufacturers for a variety of applications such as edge isolation, identification marking, laser grooving for selective emitters and cutting of silicon wafers and ribbons. In addition, several laser-processing techniques are currently being investigated for the production of new types of high performance silicon solar cells. There have also been research efforts on utilizing laser melting, laser annealing and laser texturing in the fabrication of solar cells. Recently, a number of manufacturers have been developing new generations of solar cells where they use laser ablation of dielectric layers to form selective emitters or passivated rear point contacts. Others have been utilizing lasers to drill holes through the silicon wafers for emitter-wrap-through or metal-wrap-through back-contact solar cells. Scientists at Fraunhofer ISE have demonstrated high efficiency silicon solar cells (21.7%) by using laser firing to form passivated rear point contacts in p-type silicon wafers. Investigators art both the University of Stuttgart and the University of New South Wales have produced high efficiency silicon solar cells using laser doping to form selective emitters, and some companies are now developing commercial products based on both laser doping and laser firing of contacts. The use of lasers in solar cell processing appears destined to grow given the advances that are continually being made in laser technology.

Investigation of metal contacts for silicon solar cells using laser processed 8 μm thick Al foils

“…Many studies have been focused on low temperature and vacuum-free processes for silicon solar cell fabrication. With the various fields of applications and a long history of development, laser processing has been extensively examined for solar cell fabrication and has great potential for achieving a low cost silicon solar cell fabrication process without high temperature and vacuum systems [2]. Since metallization is an important process that significantly determines the cell efficiency and manufacturing cost, the majority of laser processing research has been devoted on laser-assisted contacts.…”

Silicon solar cells based on all-laser-transferred contacts

“…More recently, laser processing has been investigated for solar cell fabrication and is drawing a great deal of attention . Laser processing is contact‐less and self‐masking by its nature and therefore has a strong potential of simplifying the solar cell manufacturing process.…”

Laser processing of materials for renewable energy applications

“…Schematic of a laser-scribed tandem junction (a-Si:H/ μ c-Si) PV module. The a-Si:H and μ c-Si layers consist of p-i-n junctions, where the interfacial region between the junctions functions as a tunnel or recombination junction 10. …”