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18: Electric Charge and Electric Field

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This chapter begins the study of electromagnetic phenomena at a fundamental level. The next several chapters will cover static electricity, moving electricity, and magnetism—collectively known as electromagnetism. In this chapter, we begin with the study of electric phenomena due to charges that are at least temporarily stationary, called electrostatics, or static electricity.

  • 18.0: Prelude to Electric Charge and Electric Field Franklin demonstrated a connection between lightning and static electricity. Sparks were drawn from a key hung on a kite string during an electrical storm. These sparks were like those produced by static electricity, such as the spark that jumps from your finger to a metal doorknob after you walk across a wool carpet.
  • 18.1: Static Electricity and Charge - Conservation of Charge When various materials are rubbed together in controlled ways, certain combinations of materials always produce one type of charge on one material and the opposite type on the other. By convention, we call one type of charge “positive”, and the other type “negative.” E.g., when glass is rubbed with silk, the glass becomes positively charged and the silk negatively charged. Since the glass and silk have opposite charges, they attract one another like clothes that have rubbed together in a dryer.
  • 18.2: Conductors and Insulators Some substances, such as metals and salty water, allow charges to move through them with relative ease. Some of the electrons in metals and similar conductors are not bound to individual atoms or sites in the material. These free electrons can move through the material much as air moves through loose sand.
  • 18.3: Coulomb's Law Through the work of scientists in the late 18th century, the main features of the electrostatic force—the existence of two types of charge, the observation that like charges repel, unlike charges attract, and the decrease of force with distance—were eventually refined, and expressed as a mathematical formula. The mathematical formula for the electrostatic force is called Coulomb’s law after the French physicist Charles Coulomb.
  • 18.4: Electric Field- Concept of a Field Revisited Contact forces, such as between a baseball and a bat, are explained on the small scale by the interaction of the charges in atoms and molecules in close proximity. They interact through forces that include the Coulomb force. Action at a distance is a force between objects that are not close enough for their atoms to “touch.” That is, they are separated by more than a few atomic diameters.
  • 18.5: Electric Field Lines- Multiple Charges Drawings using lines to represent electric fields around charged objects are very useful in visualizing field strength and direction. Since the electric field has both magnitude and direction, it is a vector. Like all vectors, the electric field can be represented by an arrow that has length proportional to its magnitude and that points in the correct direction. (We have used arrows extensively to represent force vectors, for example.)
  • 18.6: Electric Forces in Biology Classical electrostatics has an important role to play in modern molecular biology. Large molecules such as proteins, nucleic acids, and so on—so important to life—are usually electrically charged. DNA itself is highly charged; it is the electrostatic force that not only holds the molecule together but gives the molecule structure and strength.
  • 18.7: Conductors and Electric Fields in Static Equilibrium Conductors contain free charges that move easily. When excess charge is placed on a conductor or the conductor is put into a static electric field, charges in the conductor quickly respond to reach a steady state called electrostatic equilibrium.
  • 18.8: Applications of Electrostatics The study of electrostatics has proven useful in many areas. This module covers just a few of the many applications of electrostatics.
  • 18.E: Electric Charge and Electric Field (Exercises)

Thumbnail: This diagram describes the mechanisms of Coulomb's law; two equal (like) point charges repel each other, and two opposite charges attract each other, with an electrostatic force F which is directly proportional to the product of the magnitudes of each charge and inversely proportional to the square of the distance r between the charges. Regardless of attraction, repulsion, charges or distance, the magnitudes of the forces, |F| (absolute value), will always be equal. (CC-BY-3.0).

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  • TeachEngineering
  • What Is Electricity?

Lesson What Is Electricity?

Grade Level: 5 (5-6)

Time Required: 1 hours 15 minutes

Lesson Dependency: None

Subject Areas: Physical Science, Physics, Science and Technology

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  • Is It Shocking?

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Engineers make a world of difference

An understanding of electricity is important for general technological literacy. In addition, many engineering careers require a fundamental knowledge of electricity in order to invent and design technologies and products that we depend upon every day. Electricity is present everywhere in our modern lives and engineers who specialize in electricity (electrical engineers) make that possible.

After this lesson, students should be able to:

  • Relate the flow of electrons to current.
  • Correlate the flow of water with the flow of electricity in a system.
  • Explain that static electricity is the buildup of a charge (either net positive or net negative) over a surface.
  • Compare and contrast two forms of electricity—current and static.
  • Name a few engineering careers that involve electricity.

Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN) , a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g. , by state; within source by type; e.g. , science or mathematics; within type by subtype, then by grade, etc .

Ngss: next generation science standards - science, international technology and engineering educators association - technology.

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State Standards

California - science, indiana - science, oklahoma - science.

Students should be familiar with different forms of energy, including exposure to the term "electrical energy," the basics of matter, and the structure of an atom.

(Write the following sentences on the classroom board, or ask a few students to do so.)

  • Astrid turned on the computer.
  • When someone shuffles their feet on the carpet, their hair gets crazy and stands up.
  • I need to charge my cell phone battery.
  • Lightning struck during the last storm.
  • The engineer wired the circuit board.
  • A lot of power is made in the desert using solar panels.
  • After someone slides down the slide, they can shock you.

What do all these sentences have in common? (Give students some time to consider; listen to their ideas.) All these sentences involve electricity.

We use electricity every day, but you may not know what it is, how it works and how we can control it. So that you understand electricity, this lesson will build on the science you already know, such as energy, the parts of an atom and types of materials.

How many of these sentences involved an engineer or engineered technology? (See if students can figure it out; answer: 1, 3, 5 and 6.)

Everyone, take a moment to write a sentence that relates engineering and electricity? (Give students some time; then ask a few students to share their answers. As desired, provide additional information on the topic, such as: engineers make, control and give us ways to use electricity.)

Many fields of engineering require that people have a good understanding of electricity. For example, chemical engineers study the reactions responsible for producing charged particles to create electricity. Material engineers make many substances that serve as conductors and insulators. Electrical engineers are able to control electricity by changing the current or resistivity. This lesson covers the basics of electricity and materials so when we conduct the associated activity Is It Shocking? you can act as if you are engineers to select the best materials for retaining and releasing electricity.

Lesson Background and Concepts for Teachers

Prepare to show students the 19-slide What Is Electricity? Presentation , a PowerPoint® file, guided by the slide notes below. Note the critical thinking questions/answers included in the notes for slides 8, 10 and 12. For two simple classroom demos, have handy water and containers, and some inflated balloons.

Electricity is the flow or presence of charged particles (usually electrons). Remind students of the two types of charged particles in an atom (protons and electrons). Expect students to already have an appreciation for the importance of electricity, which can be cultivated by discussing as a class or creatively writing about what a day without electricity might be like (as provided on slides 1-2).

(Slide 1) While students are looking at the images of an electrical transmission tower and a wall of televisions in a store, ask them: How would your life be different with no electricity?

(Slide 2) Prompt: A power outage has just happened in your city. What actions from your daily life would not be possible without electricity? Use this hypothetical scenario to start a class discussion or creative writing exercise. For example, brainstorm as a class and then give students 15-20 minutes to write on their own.

Why do we bother learning about electricity? The point of the hooks in the first two slides is to emphasize that we constantly use electricity and that our lives would be dramatically different if we did not have access to electricity. Thus, understanding electricity is important in our daily lives.

(Slide 3) Topic preview: electricity, conductors, insulators, current, static charge.

(Slide 4) What are atoms? Expect the structure of an atom to be a review for students. If not, spend more time on this topic. Atoms are the basic unit of all elements of matter. They are made of electrons, protons and neutrons. The center nucleus contains the protons and neutrons.

(Slide 5) What are electrons? Electric charge is the physical property of matter that causes it to experience a force when near other electrically charged matter. Two types of electric charges exist—positive and negative. Positively charged substances are repelled from other positively charged substances, but attracted to negatively charged substances; negatively charged substances are repelled from negatively charged substances and attracted to positively charged substances. An object is negatively charged if it has an excess of electrons; otherwise, it is positively charged or uncharged (neutral).

(Slide 6) Students may not have an understanding of flow. As necessary, clarify with a simple demo: Have students pour water from one container to another to provide a tangible understanding of the concept of flow. The key point is that flow is movement ! Technically, electricity is the flow of any charged particles. The mnemonic device of "ELECTRicity and ELECTRons" may help students remember.

(Slide 7) Conductors are materials that are good at conducting electricity! In conductors, electrons are free to move around and flow easily. This is not true for insulators, in which the electrons are more tightly bound to the nuclei (which we'll discuss next). When current is applied, electrons move in the same direction.

In preparation for review questions, ask students to think of other metals they know about. You may want to discuss the properties of metals (bendable/ductile, metallic in color) to review students' knowledge of materials.

(Slide 8) Metals, such as copper, are conductors. Copper is an excellent conductor of electricity.

Critical thinking question: How would we test whether something is a good conductor? Answer: By connecting a wire of the material we want to test to a low-voltage battery with a light bulb connected to it. (It may be helpful to draw a sketch of this setup on the classroom board.) If the tested wire is a good conductor, the bulb lights up.

(Slide 9) In insulators, the electrons are more tightly bound to the nuclei (plural for nucleus) of the atoms. So in these materials, the electrons do not flow easily. What are some everyday examples? For example, most of our homes have fiberglass insulation that prevents inside heat from FLOWING outside through the walls of our houses, and the foam cozy that keeps soda from warming in the hot summer air temperatures.

Think about safety measures for electricians. Where would you want to put insulators? (Answer: Anywhere around conductors that you might touch, such as wires that carry electricity.)

Are the words "conductor" and "insulator" antonyms or synonyms? (Answer: Antonyms, or opposites.)

Are insulators such as glass, wood and rubber considered metals or nonmetals? Think of the periodic table and the primary elemental components of these materials (silicon for glass, carbon for wood, and carbon and oxygen for rubber). (Answer: Nonmetals.)

(Slide 10) Rubber is an example of a good insulator. Critical thinking question: We know that insulators and conductors are opposites. Do you think rubber is a good or poor conductor? Why? (Answer: Since rubber is a good insulator, it must be a poor conductor because they are opposite properties.) When students answer correctly, click to reveal the "poor conductor" bullet.

(Slide 11) Is the photograph labeled correctly with which is the conductor and which is the insulator? (Answer: Yes, this picture is labeled correctly. Copper is a metal; most metals make good conductors. Current does not flow easily through rubber, which makes it a good insulator to wrap around the copper wire.)

(Slide 12) Next we'll discuss current, which is the flow of electricity/electrons. We often use water to understand electrical systems because of their similarities. For example, water can build up pressures, like in a dam, and flow like in a river. Electricity acts the same way.

Critical thinking question: What are some examples of how we use analogies to explain more complex scientific phenomena? Examples: Humans use stories like the Greek myths to explain seasons and sunrise/sunset. We often think of materials and animals as having human "personalities" and behaviors, like saying that conductors "direct" and move electrons.

(Slide 13) In water systems, current is the flow of water. In electrical systems, current is the flow of electrons. Refer to the drawings on this slide as you relate back to the water flow demo.

(Slide 14) Let's consider static charge. How can it be explained in our water system analogy? Dammed water collects (like in a dam), but cannot flow. Static charge, or static electricity, collects charge, but cannot flow. It may help to think of the mnemonic device of: "STATIc electricity is STATIonary"—it does not move. A situation when electrons are unable to move between atoms. Thus, charge collects in a similar way to how water collects behind a dam.

(Slide 15) While showing this slide, direct students to rub inflated balloons on the hair on their heads. Ask them: What makes your hair stand up? Objects may gain or lose electrons. Rubbing the balloon on hair causes more electrons to go onto the balloon from the hair. The hair loses electrons, thus becoming positively charged (net positive charge). The balloon becomes negatively charged (net negative charge). What does the term "net" mean? (Answer: "Net" means "total.")

(Slide16) Let's go through some review questions and answers. (Note: Click to reveal the answers.) Do you think electrical current flows more easily in conductors or insulators? (Answer: Electrical current flows more easily in conductors because electrons move better in conductors. Static electricity builds up more easily in insulators because electrons cannot move well in insulators.)

(Slide 17) What do we call the flow of charged particles? (Answer: Electricity.) Does it matter if the particles are positive or negative? (Answer: No, but typically electricity is the flow of electrons—negative charge.)

(Slide 18) We have shown that copper is a conductor. Name three more conductors. (Answers: Gold, silver and aluminum.) Where would an electrician use an insulator? What type of material would it be? Why would an electrician use an insulator? (Answer: Electricians use insulator material around electrical wires and the handles of tools and other equipment. Often, electricians use rubber as the material. Insulators protect electricians from electrical shock because current does not travel very well through insulators.)

(Slide 19) If you wanted to design an electrical system that stored static electricity, would you use a conductor or an insulator? Why? (Answer: To build a static electricity storage system, you would want to use an insulator, because insulators reduce electron flow.)

(If students have had exposure to analogies, which is part of the sixth-grade curriculum in many states, use the analogy question. If not, students may need assistance on how analogies work.) Finish the analogy: River IS TO water molecules AS wire is to ______. (Answer: Electrons.)

Watch this activity on YouTube

After completing the associated static electricity activity, have students recap the activity using scientific terms to explain what happened. Then re-emphasize the water analogy to cement the connection. Ask a few additional real-world application questions:

  • Describe how engineers might control electricity in a television: What if they wanted more electricity? (Answer: Increase the current.)
  • What if they wanted to protect themselves and you from electrocution? (Answer: Use an insulator.)

atom: The basic unit of all elements of matter.

conductor: A substance that allows the easy movement of electricity.

current: Something that flows, such as a stream of water, air or electrons, in a definite direction.

electricity: The presence or movement of electric charges. Electric charge occurs when a net difference in charged particles (such as proton or electrons) exists.

electron: A particle in an atom that has a negative charge, and acts as the primary carrier of electricity.

insulator: A substance that does not allow the easy movement of electricity.

proton: A particle located in the nucleus of an atom that has a positive electrical charge.

static electricity: A stationary electric charge buildup on an insulating material.

Pre-Lesson Assessment

Discussion : As presented in the Introduction/Motivation section, guide students to realize that the five sentences on the classroom board all involve electricity. Further, have students pick out which of the sentences involve engineers and electricity. Then, have students write their own scenarios involving electricity and engineers. It may be helpful to prompt that engineers think of, design, make and control ways to use electricity.

Post-Introduction Assessment

Critical Thinking Questions : As part of the What Is Electricity? Presentation , critical thinking questions and answers are included in the notes for slides 8, 10 and 12. They are also suitable as classroom board questions or handwritten quiz questions.

Review Questions: Test students' understanding of electricity basics by asking them the seven review questions at the end of the What Is Electricity? Presentation (slides 16-19). Click to reveal the answer after each question. Alternatively, similar questions are provided in the pre-activity Electricity Review Worksheet attachment in the associated activity.

Lesson Summary Assessment

Tiny Pen Pals : To test for understanding of electrical terms, give students the Particle Pen Pals Assignment , which asks them to use terms learned in the lesson in context to describe electricity through storytelling: Pretend you are an electron and you are writing a letter to your favorite proton telling him/her that you are moving away. In this creative writing exercise, students are asked to use at least four of the following terms provided in a word bank on the handout: electricity, atom, static electricity, proton, neutron, electron, conductor, insulator and current.

Lesson Extension Activities

Assign students to investigate and research different professions in electricity and/or involving knowledge of electrical systems, as outlined in the Electrical Careers Research Project Handout . Have students present their summary paragraphs to the rest of the class.

assignment of physics electricity

This lesson introduces the concept of electricity by asking students to imagine what their life would be like without electricity. Students learn that electrons can move between atoms, leaving atoms in a charged state.

preview of 'Lights Out!' Lesson

Students come to understand static electricity by learning about the nature of electric charge, and different methods for charging objects. In a hands-on activity, students induce an electrical charge on various objects, and experiment with electrical repulsion and attraction.

preview of 'Take Charge! All About Static Electricity' Lesson

Students are introduced to the fundamental concepts of electricity. They address questions such as "How is electricity generated?" and "How is it used in every-day life?" Illustrative examples of circuit diagrams are used to help explain how electricity flows.

preview of 'Electrifying the World' Lesson

Students gain an understanding of the difference between electrical conductors and insulators, and experience recognizing a conductor by its material properties. In a hands-on activity, students build a conductivity tester to determine whether different objects are conductors or insulators.

preview of 'Go with the Flow' Lesson

"Electricity." Encyclopaedia Britannica. Encyclopaedia Britannica Online. Encyclopædia Britannica Inc. Accessed August 11, 2014. http://www.britannica.com/EBchecked/topic/182915/electricity

Headlam, Catherine (ed.). The Kingfisher Science Encyclopedia. New York, NY: Kingfisher Books, 1993.

Muir, Hazel. Science in Seconds:200 Key Concepts Explained in an Instant . New York, NY: Quercus, 2013.

Contributors

Supporting program, acknowledgements.

The contents of this digital library curriculum were developed by the Renewable Energy Systems Opportunity for Unified Research Collaboration and Education (RESOURCE) project in the College of Engineering under National Science Foundation GK-12 grant no. DGE 0948021. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: January 28, 2021

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RICEx: Electricity & Magnetism, Part 2

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Electricity & Magnetism, Part 2

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Welcome to the physics library, unit 1: one-dimensional motion, unit 2: two-dimensional motion, unit 3: forces and newton's laws of motion, unit 4: centripetal force and gravitation, unit 5: work and energy, unit 6: impacts and linear momentum, unit 7: torque and angular momentum, unit 8: oscillations and mechanical waves, unit 9: fluids, unit 10: thermodynamics, unit 11: electric charge, field, and potential, unit 12: circuits, unit 13: magnetic forces, magnetic fields, and faraday's law, unit 14: electromagnetic waves and interference, unit 15: geometric optics, unit 16: special relativity, unit 17: quantum physics, unit 18: discoveries and projects, unit 19: review for ap physics 1 exam.

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Harness Strain to Harvest Solar Energy

  • Hefei National Laboratory, Anhui, China

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The quest for an efficient method to convert solar energy into electricity is crucial in the pursuit of carbon neutrality and environmental sustainability. Traditional solar cells are based on junctions between semiconductors, where a current is produced by photogenerated carriers separated by an electric field at the junction. Efforts to enhance solar-cell performance have focused on refining semiconductor properties and on perfecting devices. Concurrently, researchers are exploring alternative photovoltaic mechanisms that could work in synergy with the junction-based photovoltaic effect to boost solar-cell efficiency. Within this context, the engineering of a strain gradient in the material has emerged as a promising research direction. In this phenomenon, known as the flexophotovoltaic effect, an inhomogeneous strain in the material produces a photovoltaic effect in the absence of a junction [ 1 ]. Now a team led by Gustau Catalan of the Catalan Institute of Nanoscience and Nanotechnology in Spain and Longlong Shu of Nanchang University in China has uncovered a pronounced flexophotovoltaic effect in halide perovskites—materials pivotal to the development of fourth-generation solar cells with high efficiency and low production costs [ 2 ]. Remarkably, the effect is orders of magnitude larger than in previously studied flexophotovoltaic materials, offering great promise for improving solar-cell technologies.

Photovoltaic effects require devices or materials that break inversion symmetry. The symmetry breaking creates a preferential direction for photogenerated electrons and holes to flow, generating a sizeable current before the carriers recombine. In traditional solar cells, symmetry is inherently broken at the interface between two different materials—a p– n junction between a hole-doped ( p ) and an electron-doped ( n ) material.

Certain materials, known as piezoelectrics, also display inversion-symmetry breaking in their crystallographic structures [ 3 ]. These materials display a bulk photovoltaic effect. Unlike the junction-based effect, the bulk one relies on a charge separation mechanism arising from the asymmetric distribution of photoexcited carriers in real and momentum space [ 4 ]. This behavior leads to unique characteristics, such as a photocurrent that depends on light polarization and a photovoltage that can exceed the band gap of the semiconducting material. In contrast, the photovoltage obtained in a junction-based device cannot exceed the material band gap, limiting the maximum power output of a solar cell, which scales with the product of photovoltage and photocurrent. With judicious design, both junction-based and bulk photovoltaic effects can operate in concert within a single device, boosting its performance. However, the bulk photovoltaic effect is typically plagued by low efficiency. What’s more, the semiconductors typically used in mainstream solar cells are centrosymmetric, hence do not display the bulk photovoltaic effect.

A viable approach to addressing this challenge involves altering the semiconductor structure to disrupt its symmetry. The engineering of a strain gradient, a deformation of the material structure that increases along a spatial coordinate, has proven to be an effective means to break inversion symmetry and induce an electric dipole in materials regardless of their symmetry [ 5 ]. Centrosymmetric materials subject to a strain gradient can exhibit the piezoelectric effect and transform mechanical energy into electrical energy, a phenomenon known as the flexoelectric effect [ 6 ]. Similarly, the breaking of inversion symmetry obtained by applying a strain gradient to a semiconductor can lead to the emergence of the bulk photovoltaic effect. This strain-gradient-induced photovoltaic effect is referred to as the flexophotovoltaic effect and was first demonstrated by Dong Jik Kim, Marin Alexe, both of the University of Warwick, UK, and me in the oxide perovskite SrTiO 3 (STO) [ 1 ]. However, the magnitude of the effect achievable in materials—in particular, those integral to solar-cell technologies—remained until now insufficiently explored.

Catalan and collaborators investigate the flexophotovoltaic effect in single crystals of two halide perovskites called MAPbBr 3 (MAPB) and MAPbI 3 (MAPI), where MA stands for methylammonium, CH 3 NH 3 . Thanks to low production cost, long carrier lifetime, and excellent charge-transport properties, these hybrid perovskites, which combine both organic and inorganic compounds, have emerged as some of most attractive solar-cell materials. These and related materials led perovskite-cell efficiency to surge from about 3% in 2009 to over 25% today—a figure that rivals that of the best silicon-based solar cells [ 7 ]. Catalan, Shu, and co-workers fabricated capacitor structures by depositing electrodes on either side of these crystals. They then bent these crystals vertically to introduce an out-of-plane strain gradient and performed experiments to characterize the flexophotovoltaic efficiency (Fig 1 ).

Since MAPB is centrosymmetric at room temperature, the MAPB capacitor generates a negligible photocurrent when flat, but bending it activates the photovoltaic effect. Under illumination, both the measured photocurrent and the photovoltage increase linearly with the applied strain gradient. The observed response outperforms that of STO by nearly 3 orders of magnitude. Furthermore, the researchers showed that by increasing the strain gradient (through an extremely large local deformation obtained by applying pressure with the tip of an atomic force microscope), they could substantially increase the photovoltage in the crystal, achieving values more than twice larger than the material’s band gap. This achievement is groundbreaking, as it marks the first demonstration of a flexophotovoltaic-induced voltage exceeding the material band gap, underscoring the vast potential of strain gradients in enhancing photovoltaic efficiency.

MAPI capacitors, on the other hand, display a substantial bulk photovoltaic effect even in the flat state. This effect is ascribed to the presence of a macroscopic polarization within the crystal whose origin has yet to be established (it may be due to either a ferroelectric effect or chemical gradients in the material). Analogous to the behavior previously observed in ferroelectric materials, this bulk photovoltaic effect in MAPI crystal can be modulated by the application of an external bias. By bending the crystal, the flexophotovoltaic effect adds to the innate bulk photovoltaic effect, leading to an enhanced or depressed photocurrent depending on the sign of the applied strain gradient. The experiments with MAPI capacitors thus show that the flexophotovoltaic effect can coexist with other bulk photovoltaic effects—offering an option for combining multiple efficiency-enhancing phenomena.

The remarkable performance of the flexophotovoltaic effect observed by Catalan, Shu, and collaborators in halide perovskite crystals validates the ability of strain gradients to boost the efficiency of solar-energy harvesting. The relatively low elastic modulus of these halide perovskite materials suggests a higher tolerance for mechanical deformation compared to traditional organic semiconductors like silicon, meaning that significant strain gradients could be incorporated in an operational device. The next step would be the demonstration of the combination of traditional and flexophotovoltaic effects. Such a step would involve designing device configurations that integrate both built-in fields at a p–n junction and strain gradients. The results obtained for halide perovskites show that the combination of the two effects holds great potential for overcoming the tyranny of the Shockley-Queisser limit—which states that the maximum efficiency of a solar cell based on a single p–n junction cannot exceed about 30%.

  • M.-M. Yang et al. , “Flexo-photovoltaic effect,” Science 360 , 904 (2018) .
  • Z. Wang et al. , “Flexophotovoltaic effect and above-band-gap photovoltage induced by strain gradients in halide perovskites,” Phys. Rev. Lett. 132 , 086902 (2024) .
  • W. G. Candy, Piezoelectricity (Dover Publications, Mineola, New York, 2018)[ Amazon ][ WorldCat ].
  • B. I. Sturman and V. M. Fridkin, The Photovoltaic and Photorefractive Effects in Noncentrosymmetric Materials (Gordon and Breach Science Publishers, Philadelphia, 1992)[ Amazon ][ WorldCat ].
  • B. Wang et al. , “Flexoelectricity in solids: Progress, challenges, and perspectives,” Prog. Mater. Sci. 106 , 100570 (2019) .
  • P. Zubko et al. , “Flexoelectric effect in solids,” Annu. Rev. Mater. Res. 43 , 387 (2013) .
  • A. K. Jena et al. , “Halide perovskite photovoltaics: Background, status, and future prospects,” Chem. Rev. 119 , 3036 (2019) .

About the Author

Image of Mingmin Yang

Mingmin Yang obtained his BS in material science from the University of Technology of Wuhan, China, in 2011 and his PhD from the University of Warwick, UK, in 2018. He then conducted postdoctoral research at the University of Warwick and the the RIKEN Center for Emergent Matter Science, Japan. After working as an assistant professor at the Department of Physics of the University of Warwick, he joined the Hefei National Laboratory in China as a research scientist and group leader. His research focus is on the study of efficient energy transduction processes in multifunctional polar materials and of devices for quantum technology, information communications, and green-energy applications.

Flexophotovoltaic Effect and Above-Band-Gap Photovoltage Induced by Strain Gradients in Halide Perovskites

Zhiguo Wang, Shengwen Shu, Xiaoyong Wei, Renhong Liang, Shanming Ke, Longlong Shu, and Gustau Catalan

Phys. Rev. Lett. 132 , 086902 (2024)

Published February 20, 2024

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Anthony Wood, a doctoral candidate in the Department of Physics at the University of Houston, is no different.

Anthony Wood

Wood is collaborating with researchers at the Fermi National Accelerator Laboratory in Illinois on a project that is examining tiny particles known as neutrinos. Neutrinos are the most abundant massive particles in the universe. The particles are smaller than electrons, do not possess electric charge and rarely interact with other atomic particles. The properties of particles are measured by the way they interact with each other, making neutrinos difficult to detect and challenging to study.

At Fermilab, Wood is working with the Imaging Cosmic and Rare Underground Signals (ICARUS) experiment. The project combines a cutting-edge detector technology with two neutrino sources, the Neutrinos at the Main Injector (NuMI) beam and the Booster Neutrino Beam (BNB). Both help to unlock the mysteries of neutrinos, a difficult task due to their low interaction probability.

“My goal during my time at the lab is to learn from experts about the ways our software is used to understand what our detector readouts can tell us about the neutrinos that interacted within it, a key task while to advance the overall experiment,” said Wood.

Fellowship at Fermilab

Wood was awarded a Graduate Student Research Award from the Department of Energy’s (DOE) Office of Science Graduate Student Research (SCGSR) Program to conduct research at Fermilab. He is one of 87 graduate students representing 33 states who received the award in 2023.

The year-long fellowship provides financial support for Wood while giving him the opportunity to conduct his research in collaboration with world-class scientists at the national laboratory that hosts this cutting-edge experiment.

“We’re working together to try to understand the fundamental aspects of how our universe works,” said Wood.

Established by the DOE, the SCGSR Program aims to enhance the training and education of graduate students in science, technology, engineering and mathematics (STEM) fields.

NuMI and ICARUS Time Projection Chamber

NuMI is a beamline that produces an intense beam of neutrinos by directing protons onto a graphite target. A spray of exotic particles exits the target and is focused by large electromagnets before they decay into neutrinos and other particles. The beam is then sent through the Earth’s crust where the other particles are absorbed, but the elusive neutrinos continue on a path toward the detector located a half-mile away.

“Only a tiny fraction of these neutrinos interact within the detector and can be measured, but there are enough for us to study their properties,” said Wood. “I’m trying to understand our simulation of the number of neutrinos that pass through our detector and how well we expect to measure them.”

This involves taking the information gathered when neutrinos interact with the detector as well as their actions before crossing paths with the detector.

“It’s like trying to reconstruct the actions of someone who left footprints in the snow,” said Wood.

ICARUS uses a time projection chamber (TPC) to measure the interaction products of neutrinos. They cannot be observed directly, but their properties can be inferred by the visible particles that come out of the interaction. The TPC is a sophisticated detector that captures the interactions of particles, including neutrinos, with unprecedented precision. This technology, only available in a lab like Fermilab, allows scientists to study neutrino properties in detail.

Advancing Knowledge of Neutrinos

Another goal of Wood’s research is to reveal insights into the role of neutrinos in the cosmos. He hopes his work will have a heavy influence in the field of particle physics.

“We’re studying neutrinos because we think they hold keys to the way the universe evolved and how nature behaves,” said Wood.

The collaboration between NuMI and ICARUS is crucial for advancing our understanding of neutrinos. By measuring particle interactions with high accuracy, Wood and other researchers can analyze the data to unravel the mysteries surrounding neutrino behavior. This has implications for our comprehension of the fundamental forces and particles that govern the universe.

Wood’s fellowship at Fermilab runs through June. When he returns to Houston, he plans to defend his dissertation and prepare a new graduate student to continue the work after he graduates.

- Chris Guillory, College of Natural Sciences and Mathematics

Browse Course Material

Course info.

  • Prof. Anant Agarwal

Departments

  • Electrical Engineering and Computer Science

As Taught In

  • Electronics

Learning Resource Types

Circuits and electronics, assignments.

Homework 1 ( PDF )

Homework 2 ( PDF )

Homework 3 ( PDF )

Homework 4 ( PDF )

Homework 5 ( PDF )

Homework 6 ( PDF )

Homework 7 ( PDF )

Homework 8 ( PDF )

Homework 9 ( PDF )

Homework 10 ( PDF )

Homework 11 ( PDF )

MIT Open Learning

IMAGES

  1. Current Electricity || Lecture 1 || Physics || Intermediate Part 2

    assignment of physics electricity

  2. 10 Science ( Physics

    assignment of physics electricity

  3. (Chapter 12 BUNDLE) A level Physics

    assignment of physics electricity

  4. Physics

    assignment of physics electricity

  5. 10 Science ( Physics

    assignment of physics electricity

  6. #02 Grade 10 Chapter Electricity of Physics

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VIDEO

  1. Electricity Part 1

  2. CURRENT ELECTRICITY||PHYSICS||CLASS12TH||LECTURE1ST||

  3. Physics

  4. Current Electricity L10

  5. Electricity Savings

  6. Steps to save Electricity 🔌:: Science Assignment ☄️

COMMENTS

  1. Assignments

    Assignments | Electricity and Magnetism | Physics | MIT OpenCourseWare Assignments The problem solving sessions were conducted during the class sessions listed in the table. In-Class problem solving counts toward 5% of the course grade. Note: The written homework assignments are not available to OCW users.

  2. Basic electrical quantities: current, voltage, power

    Science > Physics library > Circuits > Ohm's law and circuits with resistors Basic electrical quantities: current, voltage, power Google Classroom Build an intuitive understanding of current and voltage, and power. Written by Willy McAllister. Voltage and current are the cornerstone concepts in electricity.

  3. PDF Physics 122: introduction to electricity and magnetism

    Our aims in teaching Physics 122. To help you understand the physical basis of electromagnetism. To teach you how to solve problems involving forces, fields and energies created by electric charges and currents. To teach you how to solve more complex sorts of physics problems than you could hitherto, by using more of the vector algebra and ...

  4. Electric charge, field, and potential

    Unit 1 One-dimensional motion Unit 2 Two-dimensional motion Unit 3 Forces and Newton's laws of motion Unit 4 Centripetal force and gravitation Unit 5 Work and energy Unit 6 Impacts and linear momentum Unit 7 Torque and angular momentum Unit 8 Oscillations and mechanical waves Unit 9 Fluids Unit 10 Thermodynamics

  5. Electric charge, field, and potential

    Learn Electric field definition Electric field direction Magnitude of electric field created by a charge Net electric field from multiple charges in 1D Net electric field from multiple charges in 2D Electric potential energy, electric potential, and voltage Learn Electric potential energy of charges Electric potential at a point in space

  6. 18: Electric Charge and Electric Field

    18.1: Static Electricity and Charge - Conservation of Charge. When various materials are rubbed together in controlled ways, certain combinations of materials always produce one type of charge on one material and the opposite type on the other. By convention, we call one type of charge "positive", and the other type "negative.".

  7. Electric Current & Circuits Explained, Ohm's Law, Charge, Power

    This physics video tutorial explains the concept of basic electricity and electric current. It explains how DC circuits work and how to calculate voltage, current, and electrical resistance...

  8. What Is Electricity?

    1 hours 15 minutes An electricity transmission tower. copyright Summary Students are introduced to the concept of electricity by identifying it as an unseen, but pervasive and important presence in their lives. They are also introduced to the idea of engineers making, controlling and distributing electricity.

  9. RICEx: Electricity & Magnetism, Part 2

    PHYS 102x serves as an introduction to electricity and magnetism, following the standard second semester college physics sequence. Part 2 begins with the nature of the magnetic field and how it is created by current distributions and magnetic materials. Next, Faraday's law of induction is described, as well as some of its applications and ...

  10. General Physics Ii : Electricity And Magnetism (PHYS 221)

    PHYS221 Lab 3 - Google Docs. Assignments None. 4. Lab 4 - IIT Physics 221 Lab report 4. Assignments 0% (1) 4. Lab report #3 - Electric Fields and Electric Potential. Assignments 92% (12) 4.

  11. Physics II: Electricity and Magnetism

    Description: This resource contains problem solving strategies using Gauss?s law, compute the electric potential difference between two conductors, cylindrical capacitor and problems on electric field. pdf. solving04.pdf. Download File. DOWNLOAD.

  12. Electric Fields ( Read )

    An electric field surrounds every charge and acts on other charges in the vicinity. The strength of the electric field is given by the symbol E, and has the unit of Newtons/coulomb. The equation for electric field intensity is E = F q. Review. The weight of a proton is 1.64 × 10 − 26 N. The charge on a proton is + 1.60 × 10 − 19 C. If a ...

  13. Static electricity

    High school physics 12 units · 90 skills. Unit 1 One-dimensional motion. Unit 2 Forces and Newton's laws of motion. Unit 3 Two-dimensional motion. Unit 4 Uniform circular motion and gravitation. Unit 5 Work and energy. Unit 6 Linear momentum and collisions. Unit 7 Torque and angular momentum. Unit 8 Simple harmonic motion.

  14. Physics assignment: Assignment Electricity Unit 15 and B ...

    AVE-1-Introduction 2021 22 v02 Engish lang Paper 2 mark scheme Electrical charge (coulomb): The SI unit of charge, the coulomb , is the quantity of electricity carried in 1 second by a current of 1 ampere. Conversely, a current of one ampere is one coulomb of charge going past a given point per second.

  15. Physics II: Electricity and Magnetism

    The Electrostatic Videogame. Two Point Charges. Charging by Induction. The Force on a Charge Moving Through an Electric Field. The Charged Metal Slab. Torque on an Electric Dipole in a Constant Field. Instructor: Physics Department Faculty, Lecturers, and Technical Staff. Course Number:

  16. Electricity

    Assignment of Class 10, Physics Electricity - Study Material. Page 1 : 1. What is an electric circuit? Distinguish between an open and a closed, circuit.[2 marks, 2009], 2.

  17. Physics library

    Physics library 19 units · 12 skills. Unit 1 One-dimensional motion. Unit 2 Two-dimensional motion. Unit 3 Forces and Newton's laws of motion. Unit 4 Centripetal force and gravitation. Unit 5 Work and energy. Unit 6 Impacts and linear momentum. Unit 7 Torque and angular momentum.

  18. Physics

    Figure 1: Scheme of the setup used by Catalan, Shu, and co-workers to observe the flexophotovoltaic effect in halide perovskites [].Bending the halide perovskite crystal generates an out-of-plane strain gradient and induces an electrical polarization. This polarization breaks the material's inversion symmetry, enabling the conversion of incident light into electricity in the bulk material ...

  19. Physics Ph.D. Student Earns Department of Energy Fellowship at Fermi

    Anthony Wood, a physics Ph.D. student, is conducting research at the Fermi National Accelerator Laboratory (Fermilab). His work is part of a fellowship awarded by the Department of Energy's Office of Science Graduate Student Research Program.

  20. Assignments

    Assignments. Homework 1 . Homework 2 . Homework 3 . Homework 4 . Homework 5 . Homework 6 . Homework 7 . Homework 8 . Homework 9 . Homework 10 . Homework 11 . Course Info Instructor Prof. Anant Agarwal; Departments Electrical Engineering and Computer Science; As Taught In Spring 2007 ...