As of 2015, crystalline silicon (mono, and poly) dominates in the field of photovoltaics. But with interest growing in clean, renewable energies, photovoltaic generation is gaining more attention. Since photovoltaic energy is going to be a big business, a lot of research effort is going into discovering means of cheaper photovoltaic energy. Currently, the main thin film technologies receiving attention as alternate to crystalline silicon solar plates are thin film (amorphous) silicon, cadmium telluride, and cadmium indium gallium arsenide panels.
Amorphous SiliconAmorphous means not crystalline. A thin film of amorphous silicon is used to make them. Amorphous silicon solar cells are cheaper. This is because of less cost of material, processing, and energy. Mass production is easy. High temperature and shading do not affect them prominently. They show a uniform appearance which is esthetically pleasing. Thin film panels are also lighter than crystalline panels.
Their conversion efficiency is low, say, just under half of the crystalline silicon panels. Being less efficient, they take a much bigger area of panels than crystalline technologies for the same power generation. This will also increase the cost of the infrastructure. Thin film panels tend to degrade faster, and will carry a shorter warranty. Their market share remains low at the moment. If there is a breakthrough in increasing their efficiency, they may capture a greater share of the market. For more details : https://sinovoltaics.com/learning-center/solar-cells/amorphous-silicon-solar-cells-structure-and-applications/Cadmium TellurideCadmium telluride is most popular out of the thin film solar technologies here, and shows efficiency better than amorphous silicon. Also, it is considered toxic, and that is a concern. However, it is not really a threat to environment except after disposal at the end of life. Further, this threat may not be equal to that posed by the Ni-Cd chargeable batteries.
Copper Indium Gallium Selenide (CIS/CIGS)
Copper Indium Selenide (CIS) and Copper Indium Gallium Selenide (CIGS) have the best conversion efficiencies out of the thin film panels here, being close to 11 percent.. They have a much less toxic effect than the cadmium telluride cells. For more details: https://sinovoltaics.com/learning-center/solar-cells/cadmium-telluride-solar-cells-cdte-advantages/
Composition of thin-film cells. Source: SolarFacts and Advice
Other Emerging Technologies
Research is going on towards improving conversion efficiency, and various technologies are being studied. Some of these are: dye-sensitized cell, Perovskite cell, organic solar cell, inorganic solar cell, and latest, quantum dot cell.
Which technology will ultimately lead? Actually there is no ultimate result. Things can change unexpectedly, and a forgotten technology may come to the forefront as a result of a technological breakthrough.