logging in or signing up Lecture 33 SPT DEC Rosalie Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Copy Does not support media & animations WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 1481 Category: Education License: All Rights Reserved Like it (2) Dislike it (0) Added: February 19, 2008 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... By: energyrecoverysystem (20 month(s) ago) very informative Saving..... Post Reply Close Saving..... Edit Comment Close Premium member Presentation Transcript Solar Photovoltaic Technologies: Solar Photovoltaic Technologies Prof. C.S. Solanki Energy Systems Engineering IIT Bombay Lecture-33 Contents: Contents Brief summary of the previous lecture Various Thin film solar cell technologies a-Si CdTe, CIGS Thin film crystalline Si Choice of material for thin film solar cell L33- Lecture-33Thin-film technologies: Thin-film technologies L33- Lecture-33Thin-film technologies: Thin-film technologies Material direct band gap tunable band gap, 1.3 to 2.0 eV deposition techniques: PECVD,VHF-PECVD, HWCVD Light induced degradation Device structure Defects introduces the mid gap states short life time p-i-n/n-i-p structure thin i layers are advantageous good light trapping is required Tandem cells band gap profiling double junction, triple junction L33- Lecture-33Thin-film technologies: Thin-film technologies direct band gap 1.45eV(CdTe), 1.1eV(CIGS) heterojunction with n-CdS Solar cells are stable and technology is relatively cost effective material availability Toxicity of Cd L33- Lecture-33Thin-film technologies: Thin-film technologies L33- Lecture-33Thin film solar cells: Choice of material: Thin film solar cells: Choice of material GaAs efficiencies above 30%, But very expensive, mainly suited for space application, As is toxic CdTe Cd is toxic, covering large surface area with toxic material is not desirable CIGS Availability of In, 0.08 ppm, cost can go high in case of increased demand a-Si low-cost, but low stable efficiency C-Si abundant raw-material (227000 ppm) high efficiency, stable efficiency, thin-film technology provides potential to reduce the cost of wafer based cells, very attractive option to explore Candidates for thin-film solar cells: ✰ Crystalline Si(c-Si), ✰ amorphous Si (a-Si), ✰ Cadmium teluride (CdTe), Copper-indium-gallium-arsenide (CIGS), Gallium-arsenide ( GaAs) L33- Lecture-33Thin-film technologies: Case for Si: Thin-film technologies: Case for Si Calculated AM1.5 efficiencies (dashed line) and AM0 efficiencies (solid line), comparing achieved cell efficiencies (laboratory-best, confirmed) for various technologies Studies shows that if cell are made with thin-film crystalline Si such that they trap enough light, cell efficiencies greater than 20% can be obtained even in just few micron thick layer C-Si is near the maximum of this curve L33- Lecture-33Slide9: Techniques for Si usage reduction L33-Slide10: Reduction of Si-usage / pro’s – con’s L33- Lecture-33Crystalline Si films: challenges & potentials: Crystalline Si films: challenges & potentials Challenges Light trapping Surface passivation Grain boundary passivation Supporting substrate Potentials Cost-effectiveness Material quality and efficiency L33-Slide12: Contents Motivation Different thin-film solar cell technologies Why crystalline Si films? Classification based on grain size Thin-film solar cell structures Deposition techniques low temperature High temperature approaches Mono-crystalline Si thin films Other concepts L33- Lecture-33Slide13: Classification of different approaches A large number of different technologies are under parallel development A classification can be made based on different criteria: According to Tmax during layer formation According to grain size According to cell structure The R&D on the high-temperature routes is mainly driven by considerations from classical bulk Si cells Proven high efficiency and stability The R&D on the low-temperature routes is mainly driven by considerations from a-Si:H solar cells low thermal budget processing L33- Lecture-33 You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.