Thin-film PV technology

Crystalline silicon (c-Si) technology has alion’s share in the present photovoltaic (PV) industry, contributing more than 85% through the cells and modules based on poly-, mono-, and multicrystalline wafer technology (Mints and Donnelly 2011). The recent growth rate of PV industry and market is phenomenal, with asubstantial surge on average over 40% recorded globally during the last decade and expected to sustain the trend from short to medium time frame. During the early developmental phase of c-Si PV technology, the continuous feedstock support offered by Si-based electronics industry played a key role in its growth. The high purity and even second-grade wafer materials obtained at arelatively cheaper price proved favorable for PV industry as they led to areasonable efŽciency (η) Žgures for standard size modules (average η>16%–18%) and extremely good performance stability (more than 25 years) that are two essential requirements for any technology to successfully demonstrate its potential for market (Chopra et al. 2004; Jäger-Waldau 2004). However, continuously increasing demand for PV modules and the need for low-cost PV options in the last decade had stretched these advantages to the limit and had exposed some inherent disadvantages of c-Si technology, such as the scarcity of feedstock material,costly processing of materials and device fabrication steps, as well as the inability for monolithic interconnections. These, in turn, had restricted the potential of Si wafer technology and made it difŽcult to achieve PV module production cost below €1/W (1€ is about U.S. $1.35), which was considered essential for cost-competitive generation of solar electricity (Hegedus and Luque 2003; von Roedern et al. 2005; Zweibel 2000). However, recently, there has been adramatic upsurge in the production of c-Si modules in China for the last 2 years, which were made available at and below $0.6/W and as low as $0.50/W in some cases. While there is speculation that the low module cost from China perhaps did not re¡ect the real costs, the fact remains that the PV module prices have seen signiŽcant reduction in the recent years. The PV module cost depends on the total manufacturing cost