Lab 6

May 23, 2014

Today our lab consisted of examining our substrates under the Scanning Electron Microscope (SEM).

Figure 1. Scanning Electron
Microscope

A fairly simple lab today, mostly watching and observing. The substrates were placed into the vacuum sealed chamber to examine them underneath the electron microscope seen in Figure 1. The microscope essentially works by bombarding the object with electrons. The electrons that actually collide with the object are then bounced back and the computer constructs an image of the object from the bounced back electrons.

Figure 3. 90 Cycle Substrate

When done with our substrates, the computer produced the image in Figure 2 for our 30 cycle substrate and Figure 3 for our 90 cycle substrate.

Figure 2. 30 Cycle Substrate

Lab 5

May 9th, 2014

Today our lab consisted of light absorption and Photoelectrochemical (PEC) testing.

Figure 1. Light Source

The first stage of the lab was calculating the light absorption of our substrates. Since the actual absorption rate is difficult to test by itself, it was estimated through calculating the reflection and transmission percentages and subtracting those values from the total light emitted onto the substrate. The machine in Figure 1 was used to produce the light source into a fiber optic cable which could concentrate the light onto the substrate.

Figure 2. Setup for
Transmission testing

Figure 3. Setup for
Reflection testing

The transmission percentage was tested first using the setup in Figure 2. The substrate was placed in between the two black blocks in the path of the light produced from the fiber optic cable. The light transmitted was calculated by measuring the amount of light that passed through the substrate.

The reflection percentage was found using the setup in Figure 3. The substrate was placed inside the black cylinder. This was done in order to make sure that only the light transmitted through the substrate escaped and allowed for the light reflected to be measured through the output cable. 

From calculating the reflection and transmission percentages of the light emitted, the light absorbed could be estimated through subtracting those percentages from 100%.

Figure 4. PEC Testing
Setup

The final stage of the lab was the PEC testing. This test was conducted by placing the substrates in a solution of Sodium Hydroxide inside the illuminated cube setup seen in Figure 4. The illumination provided a light source for the substrate to produce a voltage, acting as an anode, and driving the water splitting reaction through the Platinum cathode. No actual water splitting was conducted, however the efficiency of the substrate was measured through the final current read through the cathode giving us an idea of how much power could be produced through the substrate and therefore, how much hydrogen could be produced.



Lab 4

May 2, 2014

Today our lab consisted of annealing the Iron(III) hydroxide into the final Iron(III) oxide.

The lab was very simple today as the annealing phase essentially involved throwing the substrate into the furnace. We conducted this in two stages. The first stage consisted of leaving the substrate in the furnace for 22 minutes at 450 degrees Fahrenheit. After that period of time had ended, the second phase was done by increasing the heat to 775 degrees and leaving it in for another 29 minutes. After this, the annealing was completed making the substrates ready for testing.

Lab 3

April 25th, 2014

Today our group conducted the coating of the Iron Hydroxide film onto the substrates.

Figure 1. Sodium Hydroxide (left) and Iron(III)
chloride hexahydrate (Right)

The first part of the lab consisted of preparing the solutions for the substrates to be dipped in and coated with. The solutions were comprised of  Sodium Hydroxide (left side of Figure 1) and Iron(III) chloride hexahydrate (Right side of Figure 1). The first made was a 0.1 molar solution of Sodium Hydroxide. The second was a 0.5 molar solution of Iron(III) chloride hexahydrate. The solutions were both mixed using the magnetic stirrer seen in Figure 2.




Figure 2. Magnetic Stirrer

Figure 3. SILAR Machine

After the synthesis of the solutions was complete, the substrates were put through successive ionic layer absorption and reaction (SILAR) using the machine seen in Figure 3. Unfortunately, while attempting to remove the substrates from the petri dish left in for storage, the titanium dioxide coating had dried and stuck to the dish for substrate 2. This resulted in the substrate being damaged on the conductive side rendering it useless. This left us with only 3 good substrates left for testing. The solutions were placed in the circular order of 6 solutions starting with the Iron(III) chloride hexahydrate, then a rinse solution of DI water, the Sodium Hydroxide to follow, another rinse, and then repeat. The substrates were held by a robotic arm inside the machine that dipped them into the solution and rotated rapidly. After the substrates were put into place, they were left to run through the SILAR for 30 cycles. After that, we removed the first substrate, and left the two others in for another 60 cycles for a total of 90.

Lab 2

April 18, 2014

Figure 1. Nitrogen Gun drying substrate

Today our group made the final preparations before actually growing the ferric oxide film onto the substrate.

First, our group took the substrates out of storage and, using a nitrogen gun in Figure 1, dried off the substrates and eliminated the ethanol it had been stored in. 

After the substrates had been dried, they were dip-coated in a solution of Titanium Dioxide (TiO2) in the machine shown in figure 2, to produce a thin film on the substrate. A calculated dip time span of 17 seconds was implemented for the coating of the substrate in order to get an ideal thickness of the film. 

Figure 2. Dip-coating of substrate

The substrates were dried, conductive side up, for approximately 30 minutes. Then the conclusion of our lab came after cleaning the equipment we'd used and throwing into the furnace at 450 degrees Fahrenheit for an hour.

Lab 1

April 11th, 2014

Today our group conducted the first stage of lab, substrate cleaning.

The process began by first identifying the conductive side of the substrate with a voltmeter and then, using a diamond tip pen, marking the backside to be able to keep track of which side was which.

After the sides were properly identified, the substrate entered the first stage of cleaning off any of the organic material. The substrate was placed in a small glass beaker and was then filled with chemical grade dish soap. These glass beakers, now containing the substrate and the soap, were placed into a larger glass beaker slightly filled with water. The large glass beaker was then put into an Ultra Sonicator; a device that produces heat to add thermal work and a high frequency through a medium, the water, to produce mechanical work. This thermal and mechanical work acted as a deeper cleanse of the substrate, rather than just shaking the beakers back and forth to have the soap do its job. The large beaker stayed in the Sonicator for a total of 15 minutes under a temperature of 60 degrees Fahrenheit. The small beakers containing the substrate were then rinsed off with Deionized water eliminating any of the soap left over to allow for the next stage of cleaning.

The next phase of the cleaning process was to then eliminate the inorganic material. The most effective way to do this was to perform the same process as the stage before, but instead of soap, an approximate 50/50 combination of ethanol and acetone was utilized. The reason for the combination is that acetone will clean off everything on the substrate, however it will leave a layer of itself even after rinsing. The ethanol acts as a "clinger" to the acetone to make sure it can be easily washed off with the Deionized water after sonication. After adding the chemical combination to the beakers, they were then placed back in the Sonicator for 15 minutes, also under 60 degrees Fahrenheit, and then rinsed off.

The final step of the cleaning process was to soak the substrate in a solution of 1 molar hydrochloric acid. This step was taken in order to get rid of any ions were still stuck to the substrate. The same procedure was taken with the first two steps but with the HCl and was placed in the sonicator for 10 minutes under the same temperature and then rinsed off.

Figure 1. Substrates stored in ethanol

After the finalization of the cleaning, the substrates were put into the small glass beakers filled with ethanol and covered, as shown in Figure 1, for storage over the next week.