In this site I will be explaining some of the chemistry behind smartphones, touch on some of the concepts of what is behind the screen of a smartphone, and get really deep into the mechanics of the smartphone and the battery. I chose smartphones as my project because they seem to be everywhere. Not only that but the companies of every smartphone made are competing as to see which smartphone is the best. So I guess that this all started from a question that i asked my friend. Why didn’t anyone want to do their project on smartphones? I mean it would be pretty easy because we live in a world full of them and you can basically research anything and everything about them. So I decided to take that idea before anyone else did. Little did I know that I was into a research overload. I found so much information that I didn’t know what to do with it. So I had to just water everything down so it would be much a simpler project.Composition of ...
- How it works
- Smartphone Chemistry
- Elements 57-71
- Scandium and yttrium
- Dysprosium and neodymium
- Smartphone’s Display
- What is behind a touchscreen
- The battery
- The electronics
Main Chemicals, Compounds, Components
The main Compounds that I decided to research for a smartphone would be the battery and the electronics.
The Battery
- Most phones use lithium ion batteries
- These batteries contain lithium cobalt oxide
- As the positive electrode
- Lighter than most rechargeable batteries
- The electrodes are constructed of lightweight lithium & carbon
- Lithium is a highly reactive element
- Lots of energy can be stored in the atomic bonds
- Translates to an extremely high energy density
- Lithium batteries lose only 5% of their charge each month
- Has no memory effect
- Don’t have to use all the battery before recharging
- Although they start to break down as soon as they leave the factory
- Lasts 2 to 3 years from manufacture date
- Extremely sensitive to high temperatures
- Heat makes the batteries to break down even faster
- DO NOT use the battery until it is dead
- The battery will be completely ruined and you won’t be able to use it anymore
- Needs a costly on board computer to manage the battery life
- There is a chance that the battery will explode if the battery pack fails
- The battery packs can come in all shapes and sizes
- On the inside of a battery pack you will find
- Lithium ion cells
- Which look an awful lot like AA battery cells
- Unless you get a square or rectangular battery cell
- A couple of temperature sensors
- A voltage converter & regulator circuit
- Which maintains safe levels of voltage & current
- A notebook connector
- Which is shielded
- Allows info in and out of the battery pack
- Voltage tap
- Monitors the energy capacity
- Battery charge state monitor
- A small computer that is in control of the charging process
- Allows the battery to charge quickly and as full as possible
- If it gets way to hot then the computer shuts down the flow of power to allow things to cool down
- On the battery there is this emergency switch
- This switch is called the Positive Temperature Coefficient(PTC)
- When the battery gets way to hot there is pressure that builds up in the battery
- If there is too much pressure then this switch will open and release the excess pressure
- Don’t allow this to happen though if it does then the battery will be ruined and you can’t use it anymore
- The battery has a metal casing
- The casing contains three long spirals of thin sheets
- A positive electrode
- Made of lithium cobalt oxide (LiCoO2)
- A negative electrode
- And a separator
- It is a micro perforated plastic
- Separates the positive and negative electrodes
- Still allows ions to pass
- On the inside the sheets are submerged in the organic solvent Ether
- Ether is the most common of the organic solvents that are used
- The solvents act as the electrolyte
- When the battery charges the ions of lithium move through the electrolyte towards the negative electrode from the positive electrode
- Then they move back towards the positive electrodes when the battery is being drained
- The movement happens at a high voltage
- Each cell produces 3.7 volts
- If the battery gets too hot the electrolyte will ignite
- Usually when a fire does start it is caused by the internal shortage of the battery
- If the separator sheet is punctured then the electrodes will touch causing the battery to heat up quickly
- If there is a puncture then the battery will become so hot that it will start venting out the organic solvent
- If it starts venting, then any amount of heat or spark will ignite it
- Once it ignites then it spills into all the other cells and the whole thing goes up in flame
The Electronics
- Elements that are used
- Copper, Silver, Gold, Tantalum
- Copper, Silver, and Gold are used for wiring
- whilst copper, gold, and silver are made into micro electrical components
- Tantalum is used as a main component for micro capacitors
- Nickel, Dysprosium, Praseodymium, Terbium, Neodymium, Gadolinium
- Nickel is found in the microphones and other electrical connections
- Neodymium, Gadolinium and Praseodymium are used in the magnets which are found in the speaker and microphone
- Terbium, Neodymium and Dysprosium are found in the vibration unit
- Silicon, Oxygen, Antimony, Arsenic, Phosphorus, Gallium
- Silicon is made into the chip in the phone
- It is exposed to Oxygen and heat
- Creates a layer of silicon dioxide on the surface
- Bits of the layer will be taken off to allow a current of electricity to flow
- Silicon can’t conduct electricity without other elements
- There are different semiconductors for each different element that is used
- Tin and Lead
- Used to solder the electronics and chip pieces together
- Now days they use a combination of tin, silver, and copper as a lead free replacement
Chemistry's Role
The Chemistry of touchscreen technology is very wide and vast. When I started this project I didn’t realize how many things there were in one little smartphone. However I was able to find lots of sources that helped! The first thing that you see chemistry being involved would be the screen. Inside the screen there are different elements that are used to produce the variety of different colors that you see. Another huge thing that the smartphone contains would be the variety of elements. For example when they solder the pieces together they use a combination of tin, silver, and copper so they heat up the elements to create the solder metal. Another example of chemistry at work in a smartphone would be the chip. Not only is the chip made of 100% silicon but when it is exposed to oxygen and heat it then undergoes a chemical reaction and creates a layer of silicon dioxide which doesn’t allow electricity to pass through. So they scrape some bits of ot to allow electricity to pass through certain spots as needed. However the one thing that used the most chemistry would be the battery. In the battery there is a thin sheet of Lithium Cobalt Oxide or LiCoO2. Which is the chemical bonding of lithium, cobalt, and oxygen. Plus there is another sheet which is made of carbon and a separator sheet. All of these are fully submerged in an organic solvent where they work together and hold electricity.
Background Research
How It works:
- There has been a variety of techniques used over the past two decades for Touchscreens
- The range being from mechanical, optical, and electrical sensing
- Today the electrical sensing has been proven to be the most useful and efficient way
- Capacitor:http://www.thefreedictionary.com/capacitor : an electric circuit used to store & charge, temporarily, consisting of two metallic plates separated from each other. Aka: condenser
- Because there is a gap a direct current of electricity(DC) can’t extend out to the other side
- An alternating current (AC) can conjure up a charge of electricity that can flow from one side of the gap to the other
- The surface of the touchscreen has a layer of electrodes laid out like a grid
- When our finger comes to contact with the screen, the AC is generated inside the device , and it connects with the corresponding current inside our body
Smartphone Chemistry:
- 70 out of the 83 elements on the periodic table can be found in your smartphone
- Smartphones may contain up to 62 different types of metals
- Rare earth metals such as scandium, yttrium, and elements 57-71
- Elements 57-71 are known as lanthanides
- One single iPhone could contain 8 different rare-earth metals
- You could find 16 of the 17 rare-earth metals if you examine several varieties of smartphones
- You won’t find promethium because it is radioactive
- Dysprosium and neodymium cause your smartphones to vibrate
- Dysprosium and neodymium are contained in magnets in your smartphones
Smartphone’s Display :
- The screens of smartphones were designed to be tough
- Actually it was the result of a serendipitous accident
- Serendipitous: The faculty of making fortunate discoveries by accident
- A chemist accidentally heated a sample of glass to 900 degrees C then he dropped it onto the floor and it bounced instead of breaking
- Hence was created the world’s first synthetic glass-ceramic
Synthetic glass-ceramic
- Shares lots of similar properties with glass and ceramic
- Glass is actually a formless solid, because it lacks a crystalline structure
- The glass molecules aren’t in any type of form the are arranged more like a liquid yet frozen in place
- Since glass does not contain atoms by which they cannot slip by each other this causes stress
- since there is no way to relieve this stress it forms a crack when excessive stress is placed on it
- Ceramics’ molecules however are often characterized by ionic bonds, even though they can also contain covalent bonds
- Because of the extremely strong bonds between the molecules it makes it difficult for the planes to slip past each other
- They resist compression but can break if bent
- The combination of glass and ceramics creates a more tougher and stronger type of material
- This material can be made by overheating the glass, so that a portion of the glass is transformed into a fine-grained crystalline material
- It is extremely heat resistant
- Glass-ceramics aka: vitroceramic, is a controlled crystallization of certain glasses
- Sometimes it is induced by nucleating additives
- In comparison to spontaneous surface crystallization, you don’t normally want it for glass manufacturing
What is Behind a Touchscreen
- There are two basic categories of touchscreens
- First resistive touchscreens
- They can be touched with any type of material and still work
- Like the ATM, or the little machine at the checkout counter where you sign your name for the credit card you use
- They are made of two layers of conductive materials
- When you touch a resistive screen the screen actually bends and touches the other layer so it connects the circuit
- The software recognizes the change in the current at the point of contact and responds by carrying out the action that corresponds with that spot
- Aka: pressure-sensitive screens
- ONLY one button can be pressed at once, if more than one is pressed at once then the software won’t respond
- Second capacitive touchscreens
- Since glass is an insulator it cannot conduct electricity
- Even though glass has ions they are locked into place which stops the electricity from flowing through
- Must be coated with a thin layer of a conductive substance
- Indium tin oxide which placed into a crisscrossing pattern
- Because your finger has an electrical charge, when you touch the screen the charge from your finger connects with the screen’s charge the software reacts to the voltage drop
- Your skin is an amazing conductor primarily due to the salt and moisture, creating an ionic solution
Resources
http://engineering.mit.edu/ask/how-do-touch-sensitive-screens-work
http://www.thefreedictionary.com/capacitor
https://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2014-2015/smartphones.html
http://www.policyinnovations.org/ideas/innovations/data/00306
http://ceramics.org/wp-content/uploads/2010/09/bulletin_oct-nov2010.pdf
http://www.compoundchem.com/2014/02/19/the-chemical-elements-of-a-smartphone/
http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery.htm
http://www.compoundchem.com/2014/02/19/the-chemical-elements-of-a-smartphone/
About the Author
Samantha Newby is a junior who attends Billings Senior High school. She attends STEM society and is currently in honors chemistry. She also has lettered in band and has participated in cross country as a manager. She enjoys spending time with her family and learning about chemistry. She loves baking and taking care of the family dogs. Learning and getting the experience to become a vet is what she wants to do. She hopes to continue to learn as much science as she can so she can attend BYU Idaho and get a 4 year degree. She decided to do her project on smartphones.