Advanced Concepts in Photovoltaics: Rsc (RSC Energy and Environment, 11) - Hardcover

Hardcover

ISBN 10: 1849735913 ISBN 13: 9781849735919

Verlag: Royal Society of Chemistry, 2014

Inhaltsangabe

Photovoltaic systems enable the sun’s energy to be converted directly into electricity using semiconductor solar cells. The ultimate goal of photovoltaic research and development is to reduce the cost of solar power to reach or even become lower than the cost of electricity generated from fossil and nuclear fuels. The power conversion efficiency and the cost per unit area of the phototvoltaic system are critical factors that determine the cost of photovoltaic electricity. Until recently, the power conversion efficiency of single-junction photovoltaic cells has been limited to approximately 33% - the socalled Shockley-Queisser limit.

This book presents the latest developments in photovoltaics which seek to either reach or surpass the Shockley-Queisser limit, and to lower the cell cost per unit area. Progress toward this ultimate goal is presented for the three generations of photovoltaic cells: the 1st generation based on crystalline silicon semiconductors; the 2nd generation based on thin film silicon, compound semiconductors, amorphous silicon, and various mesoscopic structures; and the 3rd generation based on the unique properties of nanoscale materials, new inorganic and organic photoconversion materials, highly efficient multi-junction cells with low cost solar concentration, and novel photovoltaic processes.

The extent to which photovoltaic materials and processes can meet the expectations of efficient and cost effective solar energy conversion to electricity is discussed. Written by an international team of expert contributors, and with researchers in academia, national research laboratories, and industry in mind, this book is a comprehensive guide to recent progress in photovoltaics and essential for any library or laboratory in the field.

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Über die Autorin bzw. den Autor

Professor Nozik is a Professor Adjoint in the Department of Chemistry and Biochemistry and a Senior Research Fellow Emeritus at the National Renewable Energy Laboratory (NREL) in Golden, Colorado; NREL is one of the National Laboratories of the U.S. Department of Energy.   He maintains an active interaction and collaboration with his colleagues at NREL.

Professor Conibeer is deputy director of the School of Photovoltaics and Renewable Energy Engineering at the University of New South Wales, Australia. His research interests include third generation photovoltaics; hot carrier cooling in semiconductors and phonon dispersion modulation in nanostructures.

Von der hinteren Coverseite

Photovoltaic systems enable the sun’s energy to be converted directly into electricity using semiconductor solar cells. The ultimate goal of photovoltaic research and development is to reduce the cost of solar power to reach or even become lower than the cost of electricity generated from fossil and nuclear fuels. The power conversion efficiency and the cost per unit area of the phototvoltaic system are critical factors that determine the cost of photovoltaic electricity. Until recently,the power conversion efficiency of single-junction photovoltaic cells has been limited to approximately 33% - the so-called Shockley-Queisser limit.

This book presents the latest developments in photovoltaics which seek to either reach or surpass the Shockley-Queisser limit, and to lower the cell cost per unit area. Progress toward this ultimate goal is presented for the three generations of photovoltaic cells: the 1st generation based on crystalline silicon semiconductors; the 2nd generation based on thin film silicon, compound semiconductors, amorphous silicon, and various mesoscopic structures; and the 3rd generation based on the unique properties of nanoscale materials, new inorganic and organic photoconversion materials, highly efficient multi-junction cells with low cost solar concentration, and novel photovoltaic processes.

The extent to which photovoltaic materials and processes can meet the expectations of efficient and cost effective solar energy conversion to electricity is discussed. Written by an international team of expert contributors, and with researchers in academia, national research laboratories, and industry in mind, this book is a comprehensive guide to recent progress in photovoltaics and essential for any library or laboratory in the field.

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Advanced Concepts in Photovoltaics

By Arthur J Nozik, Gavin Conibeer, Matthew C Beard

The Royal Society of Chemistry

Copyright © 2014 The Royal Society of Chemistry
All rights reserved.

ISBN: 978-1-84973-591-9

Contents

Chapter 1 Crystalline Silicon Solar Cells with High Efficiency Stefan W. Glunz, 1, 
Chapter 2 Tandem and Multiple-junction Devices Based on Thin-film Silicon Technology Christophe Ballif, Mathieu Boccard, Karin Söderström, Grégory Bugnon, Fanny Meillaud and Nicolas Wyrsch, 30, 
Chapter 3 Thin-film CdTe Photovoltaic Solar Cell Devices Timothy Gessert, Brian McCandless and Chris Ferekides, 61, 
Chapter 4 III–V Multi-junction Solar Cells Simon P. Philipps and Andreas W. Bett, 87, 
Chapter 5 Thin-film Photovoltaics Based on Earth-abundant Materials Diego Colombara, Phillip Dale, Laurence Peter, Jonathan Scragg and Susanne Siebentritt, 118, 
Chapter 6 Chemistry of Sensitizers for Dye-sensitized Solar Cells Peng Gao, Michael Grätzel and M. D. K. Nazeeruddin, 186, 
Chapter 7 Perovskite Solar Cells Nam-Gyu Park, 242, 
Chapter 8 All-oxide Photovoltaics Sven Rühle and Arie Zaban, 258, 
Chapter 9 Active Layer Limitations and Non-geminate Recombination in Polymer–Fullerene Bulk Heterojunction Solar Cells Tracey M. Clarke, Guanran Zhang and Attila J. Mozer, 287, 
Chapter 10 Singlet Fission and 1,3-Diphenylisobenzofuran as a Model Chromophore Justin C. Johnson and Josef Michl, 324, 
Chapter 11 Quantum Confined Semiconductors for Enhancing Solar Photoconversion through Multiple Exciton Generation Matthew C. Beard, Alexander H. Ip, Joseph M. Luther, Edward H. Sargent and Arthur J. Nozik, 345, 
Chapter 12 Hot Carrier Solar Cells Gavin Conibeer, Jean-François Guillemoles, Feng Yu and Hugo Levard, 279, 
Chapter 13 Intermediate Band Solar Cells Yoshitaka Okada, Tomah Sogabe and Yasushi Shoji, 425, 
Chapter 14 Spectral Conversion for Thin Film Solar Cells and Luminescent Solar Concentrators Wilfried van Sark, Jessica de Wild, Zachar Krumer, Celso de Mello Donegá and Ruud Schropp, 455, 
Chapter 15 Triplet–triplet Annihilation Up-conversion Timothy W. Schmidt and Murad J. Y. Tayebjee, 489, 
Chapter 16 Quantum Rectennas for Photovoltaics Feng Yu, Garret Moddel and Richard Corkish, 506, 
Chapter 17 Real World Efficiency Limits: the Shockley–Queisser Model as a Starting Point Pabitra K. Nayak and David Cahen, 547, 
Chapter 18 Grid Parity and its Implications for Energy Policy and Regulation Muriel Watt and Iain MacGill, 567, 
Subject Index, 596, 

CHAPTER 1

Crystalline Silicon Solar Cells with High Efficiency

STEFAN W. GLUNZ

Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg, Germany

Email: stefan.glunz@ise.fraunhofer.de

1.1 Introduction

Crystalline silicon photovoltaics is the dominant solar cell technology, with a market share of around 85% in 2012. Silicon has several advantages: It is non-toxic and abundantly available in the earth's crust. Crystalline silicon-based photovoltaic (PV) modules have proven their long-term stability over decades in the field and not only in accelerated module tests. The price reduction of silicon PV modules in the last 30 years can be described very well by a learning factor of 20%. Due to strong competition this price decline was even stronger in the last years, resulting in module prices well below $1/Wp. This is an excellent situation for customers and PV installers, but rather challenging for producers of silicon solar cells and modules. Thus cost reduction is still a major task.

The cost distribution of a crystalline silicon PV module is clearly dominated by material costs, especially by the cost of the silicon wafer and encapsulation materials (see Figure 1.1). Therefore, besides improved production technologies, the efficiency of the cells and modules is the main leverage to bring down the cost even more, especially when considering the full levelized cost of PV electricity.

The International Technology Roadmap for Photovoltaic recommends in their latest report:

(i) Continue the cost reduction per piece, along the whole value chain, but especially at the module level, by the efficient use of Si and non-Si materials, and (ii) Improve the module power/cell efficiency without significant increasing processing costs.

This chapter will mainly focus on the second route by using a detailed loss analysis to investigate the current developments and cell architectures in industry and research.

1.2 Efficiency Limitations

1.2.1 Theoretical Limitations: The Auger Limit

Based on a detailed balance calculation, Shockley and Queisser determined already as early as 1961 a maximum theoretical efficiency for solar cells. Using the AM1.5 spectrum and assuming no light concentration, the limit for a single junction solar cell is 33%. The main limitation of such cells is the thermalization of hot carriers generated by photons with energies greater than the bandgap energy and the non-absorption of photons with energy smaller than the energy gap (see Figure 1.2).

Thus, it is important to choose the right bandgap energy in order to balance and minimize these losses. Fortunately, semiconductors like silicon and GaAs are very close to the optimum bandgap energy (see Figure 1.3). However, comparing the best experimental values with the Shockley–Queisser limit (SQL), it is obvious that GaAs gets much closer to this limit.

This is actually not a consequence of a more advanced technological development, but due to the fact that the SQL is not the relevant limitation for solar cells fabricated from the indirect semiconductor crystalline silicon. In their groundbreaking article Shockley and Queisser write:

It is radiative recombination that determines the detailed balance limit for efficiency. If radiative recombination is only a fraction fc of all recombination, then the efficiency is substantially reduced below the detailed balance limit.

Other recombination channels can be caused by defect recombination, which could be controlled perfectly in theory. But there also other unavoidable intrinsic recombination channels such as non-radiative Auger recombination, which are given by the physical properties of the semiconductor. As silicon is an indirect semiconductor, radiative recombination also involves a phonon, thereby making the process quite unlikely (and silicon LEDs quite inefficient). Figure 1.4 shows the charge carrier lifetime limitation due to radiative and Auger recombination as a function of photogenerated excess carrier density. It is obvious that Auger recombination is the dominating intrinsic recombination channel for crystalline silicon in the ideal case of defect-free material.

Therefore it is very important to determine and parameterize the Auger recombination as a function of doping concentration and excess carrier density. The most recent parameterization of the intrinsic recombination (including Auger recombination) was published by Richter et al.

[MATHEMATICAL EXPRESSION OMITTED] (1.1)

(1:1) with n and p being the electron and hole density, respectively, n0 and p0 the electron and hole thermal equilibrium density, also respectively, Δn the excess carrier density, ni,eff the effective intrinsic carrier concentration, Blow the radiative recombination coefficient for lowly-doped and lowly-injected silicon (4.73 x 10-15 cm3 s-1 at 300 K;...

Details zur Ausgabe

• Verlag: Royal Society of Chemistry
• Erscheinungsdatum: 2014
• Sprache: Englisch
• ISBN 10: 1849735913
• ISBN 13: 9781849735919
• Einband: Gebundene Ausgabe
• Auflage: 1
• Anzahl der Seiten: 608
• Herausgeber: Nozik Arthur J., Conibeer Gavin, Beard Matthew C.
• Kontakt zum Hersteller: Nicht verfügbar
• Verantwortliche Person: preigu; mail@preigu.de; ; Lengericher Landstr. 19; Osnabrück; 49078; Deutschland