Beckman Group 1 is spotting a plate with ratios of iron (III) nitrate to aluminum nitrate. Their plate, 1-52, will have four different ratios of iron (III) nitrate to aluminum nitrate—1:1, 1:2, 1:3, and 1:4, each ratio having their own section on their plate. Group 2 ran Plate 2-70 with 0.01 M bismuth nitrate, since 0.03 M was not soluble. Their ratios of bismuth nitrate to iron (III) nitrate are 1:3, 1:6, and 2:3, and the fourth section solely has the pure 0.01 M solution of bismuth nitrate. They also reran Plate 2-68 with both 0.03 M chromium (III) nitrate and 0.03 M zinc (II) nitrate, using three ratios—0:1, 1:1, and 1:0. Group spotted plate 3-62 with ratios of bismuth nitrate to iron standard, which are 1:0, 1:1, and 0:1. Group 4 ran plate 4-54, the plate treated by UV for 5 minutes, as part of their efforts to discover the effects of elongated UV treatment on the coffee ring effect.
Poly: After brushing up on some conceptual understanding of band gaps, electron excitation, and the solar spectrum, we’ve decided to try spotting two solutions on one plate in order to take advantage of the band gaps of multiple materials. We hope that the relatively low band gap of Cobalt will aid in capturing a wide spectrum of light while an additional layer of Iron will actually carry out water-splitting. We’re using 0.1 M solutions of Cobalt Acetate and Iron Nitrate (the same solution as last time). In addition, we’ve taken to drying our recently-washed plates with Nitrogen, and we’re cleaning two plates with plasma again this week to further explore effect of plasma etching.
The other group cleaned eight plates using the plasma cleaner at the Atwater lab. We then went to the Kavli Nanoscience Institute to observe what a real clean room fab looks like. We took back the plasma cleaned plates to the lab and dried them with nitrogen gas to remove any remaining/gathered dust. Finally, we spotted two plasma cleaned plates with 0.1 Iron Nitrate, two with 0.1 Manganese Sulfate, two with 0.1 Cobalt Acetate, and the last two with both the Manganese solution and the Cobalt solution.
Alverno: BASIC group made an MnSO4 and TiO2 plate to see how they react with each other. They also made an Iron plate along with a Strontium and Manganese plate. They tried running plates 180306ES-1 and 180223ES-1 but had issues with dark current. CO2 group explored different concentrations of Iron standard plates and in doing so noticed crystallization on the 0.4 M plates. They made another 0.4 M Iron plate and a 0.1 M Iron plate. DOLPHIN group used a Dremel to cut metal into pieces so that they can raise the printer to fit SEAL plates inside.
San Marino Green Team: Last week’s plate had nothing but noise. In the beginning of the year, they believed they had discovered a Cu spot that was a huge hit, so they continued to play with copper. The reasoning for this plate is simply to finish “The Copper Adventure”. From the plate made last week, there was actually a solid spike in Spot #1 (Cu:Zn in a 99:1 ratio). Rather than just noise as per the plate tested last week where everything was under 0.1, Spot #1 was reproducibly good, peaking up to 0.3 on the scale while many of the other spots hovered around 0.1. They expected to have bad results to finish off the Copper narrative, but instead found something interesting— though it was still blue, it is worth looking at if Zinc is a viable combination with Copper.
Blank Team noticed there is significant flaking for the iron control spot – Fe(NO3)3 after annealing. Other spots containing Fe did show some flaking, but not as much. As concentration of iron increases, the spots flake more and more. The reason for the significant flaking is probably because the Fe(NO3)3 solution used was old and cloudy. It could also be because the plate was baked at a 450 degrees C, which is higher than normal temperature.
When the plate was placed in the base solution, before applying voltage, significant flaking occurred, specifically on the “pure” MnCl2 spots and the iron control spots. Despite the flaking of the MnCl2 spots, much of the spot material remained attached to the plate in a deformed state (in pieces instead of a round circle). The iron control spots, which had already significantly flaked after baking before placing it in the base solution, completely flaked away after being placed in the base solution. For the first scan, the dark current is around 0.5V, and applied a current of -0.002V. MnCl2 had a the highest bar (0.2V) out of all the spots. Second scan was performed with -0.002 V applied; dark current remained steady and dropped after the second scan. The third scan applied -0.005 V with dropping dark current; results are overall the same. Scan four has the same result despite the positive applied potential 0.005. Overall, given the four scans, there are no conclusive results.
They are planning to use barium for the next plate because they don’t have any cadmium. They will mix the barium salt solution with a manganese salt solution and repeat some spots containing iron using a newer solution. Since the vanadate tended to react to form new materials, they will not test it for this new plate. 10 microliters per spot of:
0.2 M MnCl2, 0.1 M Ba(NO3)2, 0.1 M ZnSO4, 0.1 M Fe(NO3)3
Ba(NO3)2 + MnCl2 (7.5 : 2.5); (5 : 5); (2.5 : 7.5)
Ba(NO3)2 + Fe(NO3)3 (7.5 : 2.5); (5 : 5); (2.5 : 7.5)
Ba(NO3)2 + ZnSO4 (7.5 : 2.5); (5 : 5); (2.5 : 7.5)
MnCl2 + Fe(NO3)3 (7.5 : 2.5); (5 : 5); (2.5 : 7.5)
MnCl2 + ZnSO4 (7.5 : 2.5); (5 : 5); (2.5 : 7.5)
ZnSO4 + Fe(NO3)3 (7.5 : 2.5); (5 : 5); (2.5 : 7.5)