Introduction to inorganic thin film solar cells

ABSTRACT: Photovoltaics stumbling block has always been its cost but it has held the promise of providing clean electricity and competitive rates. The cost is declined by a factor of nearly 150-160 times since the invention in 1954 of the modern solar cell based on cryst. silicon technol. More than 90% of the current prodn. uses 1st generation PV wafer based cSi (1st G PV) a technol. with the ability to continue to reduce its cost at its historic rate. The direct prodn. costs for cryst. silicon modules are expected to be around 1 euro/Wp in 2013, below 0.75 euro/Wp in 2020 and lower in the long term as indicated in table 1. Thin-film deposited directly on large area substrates, such as glass panels (square meter-sized and bigger) or foils (several hundred meters long) in roll-to-roll application, recognized as 2nd generation approach (II G) is always looked at as the "younger cousin" of the silicon technol., as pointed out by L.L Kazmerski. It has an inherent low-cost potential because it requires only a small amt. of expensive photo-active materials and its manuf. is suited to fully integrated processing and high throughput with a very low energy pay back time (<1.0 yr or less). It poised to take over the energy prodn. responsibilities of its older relative but it never quite fulfilling its expectations or potential except during last year when its market share moved from 6 to over 10%. During 2005- 2008-period (chapter 1 this book) the higher growth rates of the whole PV industry. The fantastic boom of thin film technol., during last years, can suggest further development principally during next years mainly due to the application of innovative concept to conventional materials and new class of thin film material coming from nanotechnologies, photonics, optical metamaterials, plasmonics and new semiconducting org. and inorg. sciences, all them recognized as 3rd generation approach (3rd G PV) to overcome efficiency limitation at low cost. Within the next 20 years, it is reasonable to expect that 2nd G PV technologies cost redns. and the implementation of some new technologies and introduction of high efficiency 3rd G PV concepts can lead to long term fully cost-competitive solar energy based on thin film approach. First, second and third generation PV are mainly based on inorg. approach. They cover a very wide area of material science and only a short overview can be outlined in this introduction leaving to the reader to analyze thoroughly the introduced concepts in the remaining part of the book as well by consulting a very wide available bibliog. partially indicated in the refs. of each chapter.