Springer Series in Materials Science 301 Arvind Shah   Editor Solar Cells and Modules Springer Series in Materials Science Volume 301 Series Editors Robert Hull, Center for Materials, Devices, and Integrated Systems, Rensselaer Polytechnic Institute, Troy, NY, USA ChennupatiJagadish,ResearchSchoolofPhysical,AustralianNationalUniversity, Canberra, ACT, Australia Yoshiyuki Kawazoe, Center for Computational Materials, Tohoku University, Sendai, Japan Jamie Kruzic, School of Mechanical & Manufacturing Engineering, UNSW Sydney, Sydney, NSW, Australia Richard M. Osgood, Department of Electrical Engineering, Columbia University, New York, USA Jürgen Parisi, Universität Oldenburg, Oldenburg, Germany Udo W. Pohl, Institute of Solid State Physics, Technical University of Berlin, Berlin, Germany Tae-Yeon Seong, Department of Materials Science & Engineering, Korea University, Seoul, Korea (Republic of) Shin-ichi Uchida, Electronics and Manufacturing, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan Zhiming M. Wang, Institute of Fundamental and Frontier Sciences - Electronic, University of Electronic Science and Technology of China, Chengdu, China TheSpringerSeriesinMaterialsSciencecoversthecompletespectrumofmaterials research and technology, including fundamental principles, physical properties, materials theory and design. Recognizing the increasing importance of materials science in future device technologies, the book titles in this series reflect the state-of-the-art in understanding and controlling the structure and properties of all important classes of materials. More information about this series at http://www.springer.com/series/856 Arvind Shah Editor Solar Cells and Modules 123 Editor ArvindShah EPFL(PV-Lab) Neuchâtel, Switzerland ISSN 0933-033X ISSN 2196-2812 (electronic) SpringerSeries inMaterials Science ISBN978-3-030-46485-1 ISBN978-3-030-46487-5 (eBook) https://doi.org/10.1007/978-3-030-46487-5 ©SpringerNatureSwitzerlandAG2020 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. 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ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSwitzerlandAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland Preface The coming years will—without any doubt—see a tremendous change in the world—climatechange,globalization,politicalupheavals,unprecedentedmigration of populations and economic instability are some keywords that come to my mind in this context. Many of us are concerned about these changes and think, in par- ticular, of climate change as a huge menace looming right in front of us. Themessageofthisbookis,however,thatthereisabsolutelynoreasonforfear; on the contrary, these changes will open up unprecedented opportunities, and new perspectives,ifonlywearepreparedtorapidlyact:collectively,collaborativelyand with courage. One of the major opportunities, which is already clearly visible, lies in the field of photovoltaics (PV). This book will tell you how and why photo- voltaicswillconstituteadecisivefactorincontributingtowardsaverypositiveand favourable development of the whole world. Let us look forward to the year 2050, just far enough that we have the time to modifybythenthewholeworld’ssupplyofenergy;justnearenough,sothatfairly accuratepredictionscanbemade.By2050,weshouldbeabletosupply50%ofthe world’stotal electricitywith PV.Whyfocus onphotovoltaics,ratherthanonother forms ofrenewable energy? Thisisbecause PVistruly unique. It istheonlyform of renewable energy that can be rapidly deployed at the necessary scale in every regionoftheworld—onruralbuildings,withincities,onmountains,indesertsand even on the surface of lakes and of the sea. Of course, onecan putPVtouseingiant installations, inthesame way, asone builds large gas power stations or huge hydroelectric dams. But photovoltaic sys- tems have tremendous flexibility, in size, form and shape. Therefore, they should preferably be used in a decentralized manner—as near as possible to the current consumer,they canindeed be installed insmall units,on theroof ofahouse, orin themidstofapond.Butwillsuchsmalldispersedunitsreallyhaveanyeffectonthe world’s supply ofelectricity? Yes, they will—because there will be many millions of them. As my mentor and guide, Shree Chamanlal Gupta of the Aurobindo Ashram in Pondicherry—the man who convinced me to start the photovoltaic laboratory in Neuchâtel—was always repeating to me: v vi Preface Illustration sponsored by Ernst Schweizer AG, Hedingen, Switzerland; illustration drawn by MichaelMeier “Remember, Arvind, the key to solve global problems is to push ahead with local solutions”. Let us now look in more detail at the “Energy Challenge”. 50% of the world’s totalelectricityby2050isatremendousamountofenergy;thiswouldbeequivalent to about 12,000 TWh per year at today’s (2020) levels of electricity consumption. This compares with 800 TWh per year that is generated by PV at present. So, this would be an increase by a factor of 15, within a period of just 30 years. As electricityconsumptionissteadilyrising,mainlyduetoeconomicgrowthinChina, India, Indonesia, Africa and South America, the actual increase we need, for PV, will probably be around a factor of 30. Canthisbedone?Fromapurelytechnicalpointofview,theansweriscertainly: «YES,WECAN».Butwehavesixotherpointstobeconsidered:(a)rawmaterials and electricity needed for the production of PV modules; (b) durability and relia- bility of PV modules—if PV is to become a pillar of humanity’s energy supply, it should be productive for 50 years or more—as all other technologies for the pro- ductionofelectricitydoandnotjustfor25to30years;(c)storage—solarelectricity comesin,inanirregularandoftenunpredictablefashion,dependingonclimateand weather,andithastobestoredinsomewaybeforeitcanbeused;(d)areasneeded forthedeploymentofthathugeamountofPV;(e)integrationofPVintotheenergy system; (f) ecological production and recycling of PV modules. Preface vii In view of these six points, we will need the collaboration of many actors: certainly, the contribution of physicists, chemists, materials scientists and engi- neers.Butwewillalsorequirethehelpofpoliticians,businessmen,bankers,home owners, architects, industry leaders and regional planners. Forthisreason,thisbookisintendedforawidespectrumofreaders—farwider than the narrow crowd of PV and solar energy specialists. As we are here looking intothenearfuture—intothecoming30years—thisbookisspeciallyintendedfor usebytheyoungergeneration—bystudentsandevenyoungstersfromhighschool. Wehavethereforetriedtokeepthisbookasaccessibleaspossible—accessiblealso to those who do not have a specialized scientific or technical education in photo- voltaics or in any related fields. At the same time, we strived to be up-to-date and include in this book the latest developments in PV. This was a difficult task, and I do not know whether we have succeeded or not. Butasareaderofthisbook,dotelluswhetherwehavereallysucceeded.Dotell us where we have gone wrong. Have we written a passage that you simply could notunderstand?Havewemadeastatementthatyouconsiderbeingwrong?Didwe leave out some information that you consider important? Are there oversights or mistakes in this book? Youcanveryeasilywritetous:youhavetheemailaddressesandalsothepostal addressesofeveryonewhohascontributedtothisbook.Wepromisetoreplytoall messages,whichcometous.Weareverymuchlookingforwardtohearfromyou. Neuchâtel, Switzerland Arvind Shah Editor of the book on behalf of all its authors Acknowledgements Theeditor,ArvindShah,isindebtedtothefollowingpeoplewhohavesignificantly contributed to the present book: (cid:129) Ambigapathy, R.: for his corrections of Chaps. 2 and 4 and for help with EXCEL (cid:129) Antognini, L. M.: for help with EXCEL (cid:129) Bacha, S.: for assistance with Chap. 12 (cid:129) Bailat, J.: for reviewing Chap. 6 (cid:129) Beck, B.: for expert assistance with basic physical concepts (cid:129) Boccard, M.: for his corrections of Chap. 7 and for help with Sect. 3.6 (cid:129) Bourée, J.-E.: for corrections of Chap. 3 (cid:129) Curtins, H.: for helpful and encouraging comments on Chap. 3 (cid:129) Etienne, B.: for encouragement and helpful inputs for Chap. 11 (cid:129) F Haug, F.-J.: for an expert review of Chap. 4 (cid:129) Fiala, P.: for his help in drawing and editing figures (cid:129) Fischer, D.: for having detected contradictions between Chaps. 1 and 13 (cid:129) Frischknecht, R.: for contributing to the discussion on sustainability of PV (cid:129) Gordon, I.: for reviewing Chap. 5 (cid:129) Guekos, G.: for advice and help with Chap. 3 (cid:129) Hofstetter, D.: for advice on basic physical concepts (cid:129) Keppner, H.: for advice and help with Chap. 3 (cid:129) Korte, L.: for his corrections of Chap. 7 (cid:129) Lux Steiner, M.: for having spotted an important mistake in Chap. 3 (cid:129) Meier, H.: for assistance with Chap. 6 (cid:129) Monokroussos, C.: for helpful comments on LETID in Chap. 10 (cid:129) Narasimhan, K. L.: for advice on Chaps. 3 and 6 (cid:129) Schock, H.-W.: for his corrections of Chap. 8 (cid:129) Schweizer, H. R.: for general encouragement with the book project ix x Acknowledgements (cid:129) Slikker, T.: for collaboration on the question of temperature coefficients (cid:129) Smestad, G.: for a multitude of actions in improving the Book (cid:129) Topič, M.: for help with Chap. 2 (cid:129) Verlinden, P.: for his corrections of Chap. 5 (cid:129) Wei, L.: for comments on PID in Chap. 10