The bright (green) spots

When sales are down, some companies tighten the R&D belt and all but halt new product development.

Jan 1st, 2010

When sales are down, some companies tighten the R&D belt and all but halt new product development. But this was not the case in 2009 for green laser diodes targeted at consumer applications and lasers applied to ‘environmentally green’ solar photovoltaic (PV) markets.

In 2009, 3.0 W Ultra-G continuous-wave lasers from Laser Operations LLC (who acquired the assets of QPC Lasers; Sylmar, CA) and 0.5 to 5.0 W 532 nm Genesis optically pumped semiconductor lasers (OPSLs) from Coherent were applied to fluorescence-based bioinstrumentation and ophthalmology applications; indium gallium nitride (InGaN) 531 nm electrically pumped true semiconductor diode lasers from Sumitomo (Kyushu, Japan) and 50 mW 515 nm green laser diodes from Osram Opto Semiconductors (Regensburg, Germany), as well as a host of other green laser diodes from Rohm (Kyoto, Japan), Nichia (Tokyo, Japan), and Rensselaer Polytechnic Institute (RPI; Troy, NY) were either deployed or in development for RGB picoprojection and other display applications; and even a tiny quantum-dot green laser from QD Laser (Tokyo, Japan) was introduced, also for picoprojection applications. In addition to being known as the year of bridging the green gap for RGB lasers, 2009 may also be known as the year in which lasers rose to prominence within the green-energy sector for solar-cell processing.

A recent article in Optoelectronics Report (www.optoelectronicsreport.com) from Finlay Colville, director of marketing, solar, for Coherent (Santa Clara, CA), said that for almost the first time, the role of laser-based tooling within solar-cell and -panel manufacturing became a topic for discussion amongst market analysts, cell makers, and production line suppliers at the 2009 European Photovoltaic Solar Energy Conference and Exhibition known as EUPVSEC, held in Hamburg, Germany in September (see www.laserfocusworld.com/articles/369627). Colville described how, in addition to surface texturing to improve light collection efficiency, edge isolation and edge-scribing of silicon/glass and thin-film substrates, and laser-grooved buried contacts, lasers were also being used in the critical creation of selective emitters to improve current collection and minimize recombination losses of solar cells. Dave Clark, senior director of strategic marketing, photovoltaics, for Newport Corporation, says that laser doping of selective emitters can increase cell efficiencies for mono- and multicrystalline solar cells as much as 2% in absolute terms--a 10% improvement compared to traditional screen-printed cells.

Even though the total number of lasers sold into the materials processing market segment for solar-cell production in 2009 was small and negatively impacted by silicon oversupply and reduced cell production (see www.laserfocusworld.com/articles/365724), there is little doubt that companies taking advantage of lasers to obtain reduced cost structures in the future will benefit when solar-cell production returns to a supply constrained condition.

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