Search query: physics of solar cells

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abstract: Photons In, Electrons Out: Basic Principles of PV Electrons and Holes in Semiconductors Generation and Recombination Junctions Analysis of the p n Junction Monocrystalline Solar Cells Thin Film Solar Cells Managing Light Over the Limit: Strategies for Higher Efficiency.
author_names: J Roy Nelson
title: The physics of solar cells
year: 2003

abstract: Characterization, material parameter extraction and subsequent optimization of solar cell devices is a highly time consuming and complex procedure. In this work, we propose a method for quick extraction of limiting material parameters in solar cell devices using a surrogate, physics embedded, neural network model. This surrogate model, implemented by an autoencoder architecture trained with a physical numerical model, allows to quickly extract the device parameters of interest at a certain process condition by using only a small number of illumination dependent current voltage (JV) measurements. Our surrogate model adequately links material parameters at a certain process condition to final device efficiency. The model provides physical insights about the location of the best performing and robust processing conditions in solar cell devices. We test our approach with GaAs and CH3NH3PbI3 (MAPbI) perovskite solar cells. The model allows to find a set of processing conditions that maximize the performance of both GaAs and MAPbI solar cells, and analogous processing conditions that minimize solar cell variability.
author_names: Zekun Ren

Siyu I P Tian

Thomas Heumueller

Erik Birgersson

Fen Lin

Armin Gerhard Aberle

Shijing Sun

Ian Marius Peters

Rolf Stangl

Christoph J Brabec

Tonio Buonassisi

Felipe Oviedo

Hansong Xue

M Thway

Kaicheng Zhang

Ning Li

Jose Dario Perea

Mariya Layurova

Yue Wang
title: Physics guided characterization and optimization of solar cells using surrogate machine learning model
venue: 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC)
year: 2019

author_names: Juan Bisquert
title: The Physics of Solar Cells: Perovskites, Organics, and Photovoltaic Fundamentals
year: 2017

abstract: Abstract Physics ruling the temperature sensitivity of photovoltaic (PV) cells is discussed. Dependences with temperature of the fundamental losses for single junction solar cells are examined and fundamental temperature coefficients (TCs) are calculated. Impacts on TCs of the incident spectrum and of variations of the bandgap with temperature are highlighted. It is shown that the unusual behavior of the bandgaps of perovskite semiconductor compounds such as CH 3 NH 3 PbI 3 x Cl x and CsSnI 3 will ultimately, in the radiative limit, give PV cells made of these materials peculiar temperature sensitivities. The different losses limiting the efficiency of present commercial cells are depicted on a p n junction diagram. This representation provides valuable information on the energy transfer mechanisms within PV cells. In particular, it is shown that an important fraction of the heat generation occurs at the junction. A review of the loss mechanisms driving the temperature coefficients of the different cell parameters (open circuit voltage V oc short circuit current density J sc fill factor FF is proposed. The temperature sensitivity of open circuit voltage is connected to the balance between generation and recombination of carriers and its variation with temperature. A general expression that relates the temperature sensitivity of V oc to the External Radiative Efficiency (ERE) of a solar cell is provided. Comparisons with experimental data are discussed. The impacts of bandgap temperature dependence and incident spectrum on the temperature sensitivity of short circuit current are demonstrated. Finally, it is argued that if the fill factor temperature sensitivity is ideally closely related to the open circuit voltage temperature sensitivity of the cell, it depends for some cells strongly on technological issues linked to carrier transport such as contact resistances.
author_names: Olivier Dupre

Rodolphe Vaillon

Martin A Green
title: Physics of the temperature coefficients of solar cells
year: 2015

abstract: 1 Problems of the Energy Economy 2 Photons 3 Semiconductors 4 Conversion of Thermal Radiation into Chemical Energy 5 Conversion of Chemical Energy into Electrical Energy 6 Basic Structure of Solar Cells 7 Limitations on Energy Conversion in Solar Cells 8 Concepts for Improving the Efficiency of Solar Cells 9 Prospects for the Future
author_names: Peter Prof Dr Wurfel

Uli Wurfel
title: Physics of solar cells from basic principles to advanced concepts
year: 2009

abstract: As technology plays a larger and larger role in the global community, areas in the developing world without consistent access to electricity are increasingly limited. Solar power is a strong candidate for rural electrification projects because of its low emission operation, but it is difficult to get a sense of the true cost, both economically and energetically, that operating different types of solar power sources incurs. Here, we seek to develop a comprehensive understanding of the resources required and energy expended in the manufacture of dye sensitized solar cells (DSCs) and silicon solar cells, as well as the total energy production capabilities of these technologies. In order to do this, a procedure was adopted and iterated upon in order to fabricate DSCs using unprocessed natural dyes from blackberries and beets, a measurement apparatus was designed to collect IV curves and the life cycles of the two technologies were examined. Comparing existing life cycle analyses (LCAs) for silicon cells with the analysis we conducted for dye sensitized cells, we concluded that dye sensitized cells can compete with silicon cells, particularly in the developing world. We found that with certain improvements to the fabrication procedure, the energy payback lifetime (the time to produce the same amount of energy expended in the production process) for a blackberry DSC could be as low as 4.2 years, and for a beet DSC could be as low as 3.3 years. Meanwhile, a silicon cell has an energy payback lifetime of 7.7 years.
author_names: Lydia Thurman
title: The Physics of Solar Cells for the Developing World
year: 2015

abstract: The rise in power conversion efficiency of organic photovoltaic (OPV) devices over the last few years has been driven by the emergence of new organic semiconductors and the growing understanding of morphological control at both the molecular and aggregation scales. Non fullerene OPVs adopting p type conjugated polymers as the donor and n type small molecules as the acceptor have exhibited steady progress, outperforming PCBM based solar cells and reaching efficiencies of over 15% in 2019. This review starts with a refreshed discussion of charge separation, recombination, and V OC loss in non fullerene OPVs, followed by a review of work undertaken to develop favorable molecular configurations required for high device performance. We summarize several key approaches that have been employed to tune the nanoscale morphology in non fullerene photovoltaic blends, comparing them (where appropriate) to their PCBM based counterparts. In particular, we discuss issues ranging from materials chemistry to solution processing and post treatments, showing how this can lead to enhanced photovoltaic properties. Particular attention is given to the control of molecular configuration through solution processing, which can have a pronounced impact on the structure of the solid state photoactive layer. Key challenges, including green solvent processing, stability and lifetime, burn in, and thickness dependence in non fullerene OPVs are briefly discussed.
author_names: Robert S Gurney

David G Lidzey

Tao Wang
title: A review of non fullerene polymer solar cells: from device physics to morphology control.
venue: Reports on progress in physics. Physical Society
year: 2019

abstract: The power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) are already higher than those of other thin film photovoltaic technologies, but the high efficiency cells are based on complicated device architectures with multiple layers of coating. A promising strategy to commercialize this emerging technology is to simplify the device structure while simultaneously maintaining high efficiency. Charge transport layers (CTLs) are generally indispensable for achieving high performance PSCs, but the high cost and possibility of instability hinder the mass production of efficient, stable PSCs in a cost effective manner. The ambipolar carrier transfer characteristic of perovskite materials makes it possible to fabricate efficient PSCs even in the absence of electron and/or hole transport layers. Encouragingly, the reported PCEs of CTL free PSCs are already over 20% However, it is still a mystery about why and how CTL free devices can work efficiently. Here, we summarize the recent strategies developed to improve the performance of CTL free PSCs, aiming at strengthening the comprehensive understanding of the fundamental carrier dynamics, heterojunction merits and device physics behind these mysteriously simple yet efficient devices. This review sheds light on identifying the limiting and determining factors in achieving high efficiency CTL free devices, and proposes some empirical charge transport models (e.g. p type doping of perovskites for HTL free PSCs, n type doping of perovskites for ETL free PSCs, constructing efficient p n heterojunctions and/or homojunctions at one side/interface or employing perovskite single crystal based lateral geometry for both HTL and ETL free PSCs, etc. that are useful to further improve device performance. In addition, an insightful perspective for the future design and commercial development of large scale, efficient and stable optoelectronic devices by employing carbon electrodes is provided.
author_names: Jin-Feng Liao

Wu-Qiang Wu

Yong Jiang

Jun-Xing Zhong

Lianzhong Wang

Dai-Bin Kuang
title: Understanding of carrier dynamics, heterojunction merits and device physics: towards designing efficient carrier transport layer free perovskite solar cells.
venue: Chemical Society reviews
year: 2019

abstract: List of Symbols.Preface.1 Problems of the Energy Economy.1.1 Energy economy.1.2 Estimate of the maximum reserves of fossil energy.1.3 The greenhouse effect.2 Photons.2.1 Black body radiation.2.2 Kirchhoff's law of radiation for non black bodies.2.3 The solar spectrum.2.4 Concentration of the solar radiation.2.5 Maximum efficiency of solar energy conversion.3 Semiconductors.3.1 Electrons in semiconductors.3.2 Holes.3.3 Doping.3.4 Quasi Fermi distributions.3.5 Generation of electrons and holes.3.6 Recombination of electrons and holes.3.7 Light emission by semiconductors.4 Conversion of Thermal Radiation into Chemical Energy.4.1 Maximum efficiency for the production of chemical energy.5 Conversion of Chemical Energy into Electrical Energy.5.1 Transport of electrons and holes.5.2 Separation of electrons and holes.5.3 Diffusion length of minority carriers.5.4 Dielectric relaxation.5.5 Ambipolar diffusion.5.6 Dember effect.5.7 Mathematical description.6 Basic Structure of Solar Cells.6.1 A chemical solar cell.6.2 Basic mechanisms in solar cells.6.3 Dye solar cell.6.4 The pn junction.6.5 pn junction with impurity recombination, two diode model.6.6 Hetero junctions.6.7 Semiconductor metal contact.6.8 The role of the electric field in solar cells.7 Limitations on Energy Conversion in Solar Cells.7.1 Maximum efficiency of solar cells.7.2 Efficiency of solar cells as a function of their energy gap.7.3 The optimal silicon solar cell.7.4 Thin film solar cells.7.5 Equivalent circuit.7.6 Temperature dependence of the open circuit voltage.7.7 Intensity dependence of the efficiency.7.8 Efficiencies of the individual energy conversion processes.8 Concepts for Improving the Efficiency of Solar Cells.8.1 Tandem cells.8.2 Concentrator cells.8.3 Thermo photovoltaic energy conversion.8.4 Impact ionization.8.5 Two step excitation in three level systems.9 Prospects for the Future.Appendix.Index.
author_names: Peter Prof Dr Wurfel
title: Physics of solar cells from principles to new concepts
year: 2005

author_names: Adolf Prof Dr Goetzberger

Jurgen Knobloch

Bernhard Voss
title: The Physics of Solar Cells
year: 2014