Crystalline silicon photovoltaic (PV) technology was first developed more than 50 years ago at Bell Labs in New Jersey based on silicon wafers, and is known as 1st generation solar technology. Silicon-based technology is technically proven and reliable, and has succeeded in achieving market penetration, primarily in off-grid remote areas and in grid-connected applications where sufficient subsidies are available to offset its high cost.
There are several inherent limitations to this 1st generation, however. Silicon wafers are fragile, making processing difficult and limiting potential applications. The process is very labor and energy intensive and manufacturing plant capital costs are high, limiting scale-up potential. And because materials represent more than 60% of manufacturing costs and silicon supply is finite, the long term potential for cost reduction is insufficient to deliver broadly affordable energy.
To simplify manufacturing and reduce costs, a 2nd generation known as thin film technologies was developed. These technologies are typically made by depositing a thin layer of photo-active material onto glass or a flexible substrate, including metal foils, and they commonly use amorphous silicon (a-Si), copper indium gallium diselenide (CIGS), or cadmium telluride (CdTe) as the semiconductor. Thin film PV is less subject to breakage when manufactured on a flexible foil. However, the promise of low cost power has not been realized, and efficiency remains lower than that of 1st generation solar. Some questions also remain about the toxic legacy of the materials, both in manufacturing and at the end of life.
It has been estimated that 3rd generation solar technologies will achieve higher efficiencies and lower costs than 1st or 2nd generation technologies (Green, M., Third Generation Photovoltaics, Advanced Solar Energy Conversion). Today, the 3rd generation approaches being investigated include dye-sensitized titania solar cells, organic photovoltaics, tandem cells, and materials that generate multiple electron-hole pairs. To maximize performance, Konarka scientists have been involved in research efforts in all of these areas, including novel combinations of these approaches.