Week+of+4-22-2013

4-24-2013 I came into the lab today and began scanning a sample of C-60 on gold.. The sample was prepared using a less than one second dip cast in 1 mg/mL CH2CL2. Matt and Jolai had been working on doing some heating experiments and I joined them right as they were heating up the sample. The before-image can be seen here below as AK.

AK-1000 Å, 32 A/D, 300 ms/line. Afterwards, it was heated for 2 seconds. AL-3718.29 Å, 4 A/D, 300 ms/line. I zoomed in to the middle of this image. There was, however, a lot of drift and so in order to find the desired area again I decided to take a large scan. AM-3718.29 Å, 4 A/D, 300 ms/line. Here we can see that the image did drift far to the left and a bit upwards. After I had found the region I needed, I zoomed in to the upper left. AN-1000 Å, 32 A/D, 300 ms/line. It is quite clear that this image is of the same area as AK. I heated up the sample for 3 seconds following this image then let the sample cool for about 10 minutes. AO-3718.29 Å, 4 A/D, 300 ms/line. I zoomed into upper right. There was a lot of drift so I rescanned the same area to find the region from before. AP-3718.29 Å, 4 A/D, 300 ms/line. I zoomed into the middle of this region to take a scan of the region from AK and AN. AQ- 1000 Å, 4 A/D, 300 ms/line. I heated the sample up for 3 seconds. The tip crashed as I was turning the heater off and then about 10 seconds later, the tip un-crashed. AR-3718.29 Å, 4 A/D, 300 ms/line. This image does not appear to resemble the same general area seen in the previous large-scale areas. This is almost definitely caused by a large amount of drift provoked by the tip crashing into the sample. AK-AN There is a clear deterioration in the tip's quality that can be seen between the images AK and AN here and even more so in AQ. A molecular structure is visible throughout much of AK on the right. Much of this structure has been obscured in AN and is covered in noise and streaks caused by the tip. I have outlined some fairly noticeable changes between the two images though these are not the only ones. The one in the furthest upper left could change simply as a result of the tip and it seems to me that that change is more just a malfunction of the tip rather than an actual change in the molecules. The black outline right next to that one features a large group of C-60 molecules grouped on top of a mount in AK. In AN, there does not appear to be as many of these molecules and they appear to be even more disorganized. Below these two outlines is what I perceive to be only one bonded molecule while in the image on the right, it appears to have separated into two distinct molecules, possibly a consequence of the heating. The same thing seems to have occurred to the large molecule in the outline in the lower right. This time it also appears to have decomposed into two separate molecules. The three molecules in the black outline in the upper right seem to have disappeared completely which is quite interesting itself. Today provided some decent evidence that we will actually be able to obtain some legitimate results when we have a better sample and a better tip. We were definitely able to get the scope to scan the same area after heating several times and future experiments look promising. Matt will be preparing the sample using Pentane as a solvent because it is much more volatile so will be less likely to stick to the surface and to interact with the C-60 molecules; it will evaporate quickly and will allow for a better sample.

4-25-2013 I came into the lab today and began scanning a sample of C-60 on gold. The sample was dip cast in supersaturated n-Pentane for less than one second. AP-1000 Å, 32 A/D, 200 ms/line. I rescanned this image because of the drift near the end AQ-1000 Å, 32A/D, 200 ms/line. I zoomed out and took a full-scale image afterwards. This image features a large amount of streaks and the bright spots on this image, which could possibly indicate the surface molecules, are too blurred out by the tip for us to actually observe any of their real qualities. AR-3718.29 Å, 4 A/D, 300 ms/line. I zoomed in to the lower middle AS-1000 Å, 32 A/D, 300 ms/line. I moved the scanning region slightly up and to the right to avoid the junk on the bottom part of this image. Here we see a fairly blurry surface caused by most likely the tip and the quality of the sample. The sample prep does not appear to have created a sample with the desired monolayer that we are looking for. Also, it appears that the tip is obscuring anything on the surface that we might have been able to see anyway. AT-1000 Å, 32 A/D, 200 ms/line. I moved the scanning region upwards. This image displays a high level of blurriness which prevents us from observing the molecular structure of the surface and the C-60 molecules. Streaks are abundant no clear structure is apparent here. AU-1000 Å, 32 A/D, 200 ms/line. This image is definitely an improvement from the one before but it is still blurry. The few large-scale streaks in the middle of the image caused by the opening and closing of the door to the room caused the image to look blurrier than it might have actually been. This image still lacks the molecular definition that we are looking for in this experiment. I moved the tip slightly up and to the left. AV-1000 Å, 32 A/D, 200 ms/line. The C-60 molecules are present in this image as the bright spots on top of the otherwise gray surface. They are faintly, however, only faintly apparent and their boundaries are not well defined. They are indiscrete here and the tip's lack of quality obscures their relationship to the other molecules and the surface as a whole. I moved the tip far off to the right. AW-1000 Å, 32 A/D, 200 ms/line. This image is just simply incomprehensible. There was a lot of strange noise so I scanned it again. AX-1000 Å, 32 A/D, 200 ms/line. There wasn't much improvement from the last image to this. There are still way too many streaks and nothing can be clearly distinguished on the surface. I moved the scanning region up. AY-1000 Å, 32 A/D, 200 ms/line. The bottom portion of intense streaks almost completely obscured the rest of the image when I processed the scan.The surface here looks like nonsense and the bright spots appear to simply be junk rather than actual molecules. I moved the scanning region up and to the left. AZ- 1000 Å, 32 A/D, 200 ms/line. This image is not much better than the last one solely because of how blurry it is. Surface features are faintly visible but are mostly obscured because of the tip. I moved the tip down and to the right. BA- 1000 Å, 32 A/D, 200 ms/line. This image shows a bit of improvement. It is somewhat more clear that there the bright spots in the lower third are C-60 molecules though their boundaries themselves are heavily obscured. I moved the tip up and to the right. BB-1000 Å, 32 A/D, 200 ms/line. The surface features seem to be faintly present in the upper third of this image but are obscured by the streaks across the image. After the first third, the image decreases heavily in quality and looks simply like nonsense without any real structure present. I moved the tip to the right. BC-1000 Å, 32 A/D, 200 ms/line. Surface structures do not appear to be present in this image at all. Edge boundaries are indiscrete and streaks obscure the entirety of the image, especially in the bottom half. I moved the tip to the bottom left of the macro image. BD-1000 Å, 32 A/D, 200 ms/line. There are few C-60 molecules which can be observed here but there is still an improvement in the image quality in this image. The boundaries between the surface and the pits are much more defined in the lower half of this image and it is not as streaky as the last few images. I moved the tip up. BE-1000 Å, 32 A/D, 200 ms/line. This image here shows a very blurred surface, a lot of which can be attributed to the tip and to the incredible difference in height in the uppermost portion of the image. Streaks also plague this image, obscuring the boundaries between the pits and the surface. I moved the tip to the bottom right. BF- 1000 Å, 32 A/D, 200 ms/line. This image is incredibly blurry because of the tip nonsense that occurred in the first third of the image. I attempted to rescan this area twice and each time the same problem occurred. After the third time, I moved the tip to the upper left corner. BG-1000 Å, 32 A/D, 200 ms/line. Here the surface molecules are are more clearly represented in the upper left quadrant of the image. However, the rest of the image is completely blurred out by streaks and offeres no insight into the molecular structure of the sample. I zoomed in to the upper left corner of this image. BH-1000 Å, 32 A/D, 200 ms/line. This image was mostly disappointing but also sort of expected. The quality had not been high all day and this image is consistent with that. The tip blurs out almost completely what could be the surface molecules present here. Streaks obscure the boundaries between the molecules and the surface and between the pits and the surface. The day's failures can be attributed mostly to the tip's lack of sharpness and to the sample as the prep did not create the type of surface monolayer that we wanted.