Chapter 229: After good night is the beginning of night life

Exiting the simulation laboratory II, Xu Qiu went to the vacuum oven and turned off the heating device and vacuum pump.
Then, rotate the vent hole on the side of the instrument and carefully put the air into the vacuum oven. If the venting rate is too high, the solid powdery medicine wrapped in the filter paper may be blown away, causing the experiment to directly GG.
The barometer on the vacuum oven rose slowly and returned to normal atmospheric pressure after about half a minute.
Xu Qiu turned the handle, opened the oven door, took out the filter paper bag, and carefully unfolded it.
The filter paper was baked warmly, and the dark red powder on it was completely dry at this time, and there was no trace of solvent.
After all, the set temperature is 70 degrees Celsius, which has exceeded the boiling point of methanol solvent about 65 degrees Celsius. Therefore, although the drying time is only more than one hour, the task has been successfully completed.
In fact, if you are not in a hurry to cast a reaction, the best treatment is 40 or 50 degrees Celsius, vacuum drying the medicine at a relatively low temperature, and then lasting longer, such as 6 hours or even overnight.
The main consideration is that under high temperature conditions, it may cause the decomposition of drug molecules. For example, drugs such as organotin reagents may be detinned. However, the chemical stability of PDI molecules is very good, so don't worry too much.
Xu Qiu used a stainless steel spatula to transfer the second-generation 3D-PDI molecules on the filter paper to the weighing paper and weighed the mass.
41.2 mg.
The quality of the raw materials is higher than when it was initially fed.
This is also normal. The nitration reaction is to replace a hydrogen atom with a nitro group and introduce three nitro groups to the molecule, which can increase the relative molecular mass of about 135.
After calculation, the yield is 99.6%, rounded up to 100%!
Xu Qiu collected the product and began to prepare for the next reaction-at high temperatures, the selenium powder reacts with the second-generation 3D-PDI molecules of trinitration.
In this reaction, the selenium atom replaces the position of the nitro group and at the same time connects with another bay carbon atom on the current PDI molecule to form a single bond again.
In layman's terms, (1, 2), (3, 4), (5, 6), six active sites, for the nitration reaction in the previous step, only one site is taken each.
For selenium atoms, I’m sorry, I want them all. Each selenium atom occupies two active sites in the bay, forming a five-membered ring structure.
This is why the reaction in the previous step does not need to distinguish the three products.
Because even if it is a mixed product, the reaction of introducing selenium atoms through this step will eventually return to a unified final product.
Xu Qiu walked to the reagent cabinet, took out the reagent bottle containing selenium powder and the N-methylpyrrolidone solvent bottle, and transferred them to the fume hood.
Selenium powder is an inorganic non-metallic material. There are not many organic solvents that can dissolve it. It is soluble in concentrated sulfuric acid and chloroform, slightly soluble in carbon disulfide, and insoluble in water and ethanol.
Obviously, concentrated sulfuric acid is not a good choice for solvent. Trichloromethane, that is, chloroform, has a boiling point that is too low, only about 60 degrees Celsius, which is also not suitable for this reaction.
Therefore, the solvent selected this time is N-methylpyrrolidone, or NMP for short, which is a strong polar solvent. It can not only dissolve selenium powder, but also has a boiling point of more than 200 degrees Celsius, which is very suitable for this reaction.
NMP is a colorless transparent oily liquid with a certain viscosity, which is different from commonly used toluene, methylene chloride and other low viscosity.
It is said that this thing has the smell of amine, but Xu Qiu didn't go up to sniff it.
He directly used a disposable dropper to draw about 10 ml of solvent into the two-necked flask. This time, he didn't need to re-evaporate the solvent, which was easier.
After fixing the reaction solvent, Xu Qiu picked up the reagent bottle of selenium powder and looked at it.
It is marked with "Sepowder, high-purity selenium powder, the CAS number of the drug, 7782-49-2, and manufacturer-related information.
The CAS number of a drug is very similar to the ID number of a resident. Each CAS number usually corresponds to only one drug, but the same drug may correspond to multiple CAS numbers.
Xu Qiu has checked the information before, and selenium powder is toxic and powdery, and it is easy to diffuse into the air during the weighing process.
Therefore, he took the reagent bottle of selenium powder into a fume hood dedicated to inorganic synthesis reaction and weighed it with the balance here.
Open the fume hood, pull the glass of the fume hood to the bottom, unscrew the reagent bottle cap of the selenium powder, scoop a small spoonful of black-gray powdered selenium powder with a medicine spoon, and transfer it to the weighing paper on the tray of the peeled balance. The glass door on the side of the upper balance.
The selenium powder in this reaction is greatly excessive, so the weighing does not need to be particularly precise.
In the end, Xu Qiu weighed 40.1 mg of selenium powder and quickly transferred it to a two-necked flask, which was about 30 equivalents relative to the nitrated 3D-PDI molecule.
He grabbed a clean shuttle-shaped magnetic stirrer, threw it into the reaction flask, clamped the reaction flask on the iron clamp, immersed it in the oil bath, started heating and stirring, set the temperature to 70 degrees Celsius, and the speed of 400r.p.m.
While waiting for the selenium powder to dissolve, Xu Qiu started to prepare. This reaction requires nitrogen protection and does not need to be refluxed. Just use a three-way valve to get a nitrogen ball.
Afterwards, install a nitrogen ball, three pumps and three rows, add the nitrated 3D-PDI raw material, three pumps and three rows, quickly increase the temperature to 190 degrees Celsius, increase the speed to 700r.p.m., and wrap the reaction flask with aluminum foil.
"Finally finished." Xu Qiu muttered to himself, and looked at the stopwatch hanging next to the fume hood, "It's almost 11 o'clock, it's almost 12 o'clock, let's send a message to the school girl first."
Remove the sweaty gloves, take off the lab coat, and return to A501.
Picking up the phone and looking at it, he received a row of messages from school girls.
"Brother, I'm in the bedroom."
"After taking a shower."
"[What about people]"
"So sleepy."
"I really want to sleep."
"[voice]"
"[voice]"
Xu Qiu clicked on two voices, and the school girl’s soft voice came from the earpiece, "Hoo~ I almost fell asleep." "Wait for me, I will wash my face again."
‘It’s really nice to have someone miss you,’ Xu Qiu smiled, and just wanted to reply, he received another message.
"Grand Summoning, show up, brother."
"[I'm coming]"
"Hey, the call is really successful."
"I have been experimenting before. I didn't bring a mobile phone. I just finished my work."
"Brother has worked hard, the experiment is going well."
"not bad."
The two chatted for a while, and said goodnight to each other.
As we all know, staying up all night begins after good night.
Xu Qiu put down the phone and returned to the laboratory.
He was eager to report safety to the school girl just now, and the laboratory has not been closed yet.
After checking several fume hoods, several reaction flasks were normal, Xu Qiu then safely turned off the laboratory's water, electricity, and gas, locked the door and left.
Back to A501, brush your teeth and wash your face. Unfortunately, the conditions here are not allowed and there is no way to take a bath.
Although the bathroom in the Handan dormitory only has cold water supply, it has at least one spray head. If you use a warm kettle to get two pots of boiling water downstairs, you can even take a hot bath with the shower head.
The school girl goes back late every day. That's how she takes a bath. As for how Xu Qiu knew, he didn't ask him actively anyway.
But Zhang Jiang didn't even have a shower in the bathroom.
It is normal, after all, it is a laboratory building, not a dormitory.
For this reason, there is a sprinkler and eyewash in the corridor on the fifth floor, right next to the A502 gate, but this is for emergency use in case of an accident and cannot be used for personal use.
For example, if you accidentally spill chemical reagents into your eyes, you can use an eyewash to provide plenty of water to rinse your eyes, or your clothes catch fire, you can use a shower to soothe your heart.
Putting aside the mess of thoughts in his mind, Xu Qiu glanced at the time, and it was past twelve in the morning.
Decisively lay down on the bed, closed his eyes and counted the sheep for a while, and fell asleep.
...
The sun is shining and a new day is here.
Xu Qiu woke up at 8 o'clock, after a simple wash, went to the cafeteria to settle breakfast.
On the way, he entered the simulation laboratory II to check the results. The three first-generation 3D-PDI molecules, namely the PDI3-B-5/6/8 series, have completed the preliminary exploration of photoelectric properties.
Because of the previous exploration experience (the first generation 5/6 series, the 6 series is higher, the highest value is 4.37%), this time the simulation experimenters have more detailed control of the parameters, and the final photoelectric efficiency of the device is higher. Improved once.
Of course, it may also be because the product of this reaction is better.
Regardless, the final result is that the efficiency of the first-generation 5 series is still at the bottom, the highest efficiency is 4.22%, the photoelectric performance of the 6 series and the 8 series are equivalent, and the highest value is 4.55 respectively. Based on the existing donor library, the best fit is The body materials are all P3TEA, and the suboptimal aptamer donor materials are all PCE10.
With this result, Xu Qiu began to analyze.
Last week, the second-generation 3D-PDI was the 5 series of molecules obtained through the photocyclization reaction. The highest efficiency reached 5.41%. If it is replaced with the 6/8 series, the probability can be increased again, perhaps 6%.
Unfortunately, in the first generation of 3D-PDI, the efficiency of the 8 series is not obvious compared to the 6 series, only 0.05%. It is rounded to 0. It is not clear that these two in the subsequent second and third generations Whether the series can widen the gap.
At present, the third-generation 5 series 3D-PDI that is still performing the selenization reaction in the laboratory is very critical. If it is improved compared to the second-generation 5 series, it is likely that this strategy can be simultaneously applied to 6 /8 series.
So, today’s task is also determined, to cast three reactions to synthesize the second-generation 5/6/8 series molecules in large quantities, and do the post-processing of the third-generation 5 series molecules.
Back to the Microelectronics Building, Xu Qiu went to the laboratory alone before the school sister and school girl came, opening the windows for ventilation.
The expected reaction time of the selenization reaction is 12 hours and the high temperature is 190 degrees Celsius. The reaction conditions are relatively fierce, but because of the nitrogen protection, the chemical stability of the PDI molecule and there are no possible side reactions, there is not much to worry about.
Xu Qiu originally wanted to check the board, but the high temperature reaction plus nitrogen protection, the solution in the reaction flask must be cooled to room temperature, and then the solution in the reaction flask must be reduced to room temperature. So I had to give up.
‘Anyway, I’m not in a hurry, so I’ll wait for another three or four hours. It’s just that time for the three responses. ’
Thinking of this, Xu Qiu began to prepare for the experiment. There is only one raw material for the photocyclization reaction, which is the first-generation 3D-PDI molecule, with iodine as a catalyst.
In fact, it is not very rigorous to say that iodine is a catalyst, because the composition, chemical properties and quality of the catalyst itself do not change before and after the reaction. In fact, iodine is consumed during the reaction. When two carbon atoms form a ring, When directly connected with a carbon-carbon single bond, two hydrogen atoms will be removed, and it will just be combined with iodine to form hydrogen iodide.
Xu Qiu first set up the device to distill toluene, and then checked the purity of the three reaction raw materials.
Everything was ready. He took three clean reaction flasks and added the weighed three first-generation 3D-PDI molecules. In this reaction, he directly used all the stocks obtained from yesterday’s separation and purification. About 300-400 mg.
Then, add 100 ml of re-steamed toluene to dissolve the raw materials, add 1 mg of iodine, and set up a 500-watt high-pressure mercury lamp to start the reaction.
Xu Qiu was very careful during the whole process, because this time it was a large-scale reaction, and there was no room for loss.
...
At about 9:30, Chen Wanqing and Han Jiaying appeared at the gate of A501 together.
The three chatted and laughed for a while, Xu Qiu stayed in the office, and the other two went to the laboratory.
Thinking about the cover of the article yesterday, Xu Qiu sent Tian Qing a WeChat message: "Sister Tian Qing, how about the cover?"
I received a reply soon, "I have already made a first draft, how do you think?" "[Picture]"
Xu Qiu clicked on the picture. It was obviously hand-painted by Tian Qing. The overall style is the same cartoon style as before, but now it is not completely colored, and some of it is simply outlined.
The content is very rich. It can be seen that she has made a lot of work, and her understanding of organic photovoltaics is not low.
On the upper left is a golden sun, constantly radiating sunlight as the start of energy;
On the upper right are the cartoonized PCE11 molecules and PC[70]BM molecules, grinning and holding hands, seeming to say "we all have a bright future", which is the core highlight of Xu Qiu's article.
The bottom left is an anatomical view of the layers of the organic solar cell device, including glass substrate/ITO/transport layer 1/effective layer/transmission layer 2/metal electrode; the bottom right is an enlarged view of the effective layer, or the microscopic appearance .
In these two parts ~EbookFREE.me~ Tian Qing shows the whole process of converting solar light energy into electrical energy:
The material absorbs light energy, generates excitons (electron/hole pairs), splits excitons into free electrons/holes, free electrons/holes are transported inside the acceptor/donor, and electrons/holes are electrode Collect to form photocurrent.
On the whole, Xu Qiu was quite satisfied, and replied: "The painting is good, I have shown it to Teacher Wei."
"I've seen it, he said it's okay, do you have any comments, brother?" Tian Qing replied.
"The core of PC[70]BM is that the C-70 is ellipsoidal. The figure is drawn as a spherical shape, and it can be changed." Xu Qiu thought for a while and asked a small question.
"Okay, I'll change it, I will be lustful today, and I will post it with PS to finalize it."
"Sister Tian Qing has worked hard, wait for me to invite you to dinner."
PS: I asked for a monthly pass at the beginning of the month. Last month, I updated almost 20W characters. This month I will continue to cheer for more outbreaks!