Chapter 445: 1 week of Liver Emperor, Y series materials are available

After the group meeting, everyone returned to 216.
After a while, Wu Feifei suddenly said excitedly: "My visa has been passed, and Xu Qiu and Han Jiaying should check it out soon."
Xu Qiu glanced at Wu Feifei’s computer screen. The page on the browser was the Beautiful Country Visa Center, with
Issued
on the top, and the applicant’s AA code, passport issuance time, and a paragraph in English below. Remarks: "Your visa has been passed. If you do not receive the visa within 10 working days, please contact..."
"It's pretty fast." Xu Qiu casually responded, and then checked with Han Jiaying and found that their visa status also showed "Issued", so they said: "Our visa has passed."
"You are all lucky, none of them have been reviewed. "I just don't know how long the validity period of the visa application is..." Tian Qing explained: "There are several levels of validity for tourist visas like beautiful countries, they are 3 Months, 1 year, 3 years, 5 years, 10 years, and permanent validity. The valid period of the tourist visa I applied for before is 5 years, which is relatively long. "
"By the way, after you receive your passport, remember to go to the EUVS website to update your information. This must be updated before you go to the beautiful country. If you don't update it, your entry will be affected." Tian Qington After a pause, he added:
"Oh, and this website is free. Sometimes if you want to directly search for a fake official website, you will be charged dozens of dollars in handling fees. Remember not to be scammed by Qiandu."
Wu Feifei responded with a smile: "I didn't expect Qiandu's business to expand so extensively. It used to be an advertisement for selling shoes, and an advertisement for receiving hospitals. Now they have successfully connected with the international community."
...
After lunch, Xu Qiu went to the Jiangwan campus by himself. His work plan this week was to synthesize the Y series of receptor materials, and at the same time to complete the writing of the "Joule" article between experiments.
Han Jiaying and Wu Shengnan have both stayed at the Handan campus. The school girl will prepare battery devices based on PTQ1 this week and also perform other characterization tests. The postdoctoral sister will communicate with Wei Xingsi about the fund project in real time this week.
The other two undergraduates, Yin Houlang and Xu Xinjie, both stayed at the Handan campus.
In fact, Xu Qiu doesn't mind bringing two newcomers in the area personally, but the new undergraduates have a special attitude towards him...
How to describe it? Probably respectful and alienated, a bit similar to how he looked at Wei Xingsi when he first joined the group.
Before he knew it, Xu Qiu's student identity was quietly fading, and he gradually transformed into a leader of a research team.
At about one in the afternoon, Xu Qiu arrived at the Jiangwan campus and first came to the student office on the fourth floor of Xiancai to rest.
Someone moved in in the big office today, three men and one woman, who seem to belong to the same research group.
Xu Qiu speculated that it might be the laboratory of other research groups in Jiangwan, which has been almost renovated, and plans to relocate to Jiangwan in response to the school's call.
However, Xu Qiu didn't know any of these four people, so he didn't say hello to them, and directly took out the key to open the door and entered the small office inside.
After scanning the office and seeing Han Jiaying's table, Xu Qiu decisively chose "Dove to occupy the magpie's nest" and occupied the position of the school girl.
Because the school girl’s chair has a soft cushion, it is more comfortable to sit on, and the surrounding decoration is also very good, which can make people happy and get a work efficiency +10% BUFF.
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Sitting on the chair, Xu Qiu turned on the laptop and began to plan the experiment. It seemed that she could still smell the smell of the school girl, and she didn't know if it was an illusion.
For the Y series of receptor materials, Xu Qiu actually had the consideration of "simplifying the synthesis steps of receptor materials and reducing the cost of receptor materials" at the beginning of the design.
For example, the synthesis of Y5 material is because Y4 uses the ICIN-2F end group, which is relatively difficult to synthesize, so ICIN-2Cl end group is used instead.
Originally, Xu Qiu didn't expect the performance of Y5 to be so good, but the result is correct. The performance of Y5 is better than Y4, and the highest device efficiency has reached 14.8%.
During this period, Xu Qiu also made further "optimization" of Y5 with reference to the previous experience of the ITIC system.
Using the simulation laboratory, Xu Qiu designed and synthesized Y6-Y11, a total of 6 receptor materials.
Unfortunately, the device performance of these materials has not made further breakthroughs, and still stays at the level of 12-14% efficiency.
Specifically, Y6 is relative to Y3. The ICIN of the Y3 end group is changed to ICIN-M, which is considered to be a material of the same series as Y4 and Y5. Although the device efficiency is slightly worse than that of Y4, it has reached 14 %+.
The subsequent Y7-Y11 are all "improvements" relative to Y5.
Among them, Y7 is the thienothiophene TT connected to the NT unit in Y5, replaced by thienothienothiophene TTT, which is used to broaden the conjugation length of the central unit, with a maximum efficiency of 12%+.
Y8 and Y9 modify the side chain on the nitrogen atom of the NT unit in the Y5 molecule. Y5 uses 2-ethylhexyl, Y8 uses a linear alkyl group with the same number of carbon atoms—n-hexyl, and Y9 uses It is 2-butyldecyl with 4 more carbon atoms. The efficiencies of Y8 and Y9 are both 13%+, which does not exceed Y5.
Y10 and Y11 modify the side chain on the N atom at the junction of the NT unit and the TT unit in the Y5 molecule. Y5 is also 2-ethylhexyl, and Y10 and Y11 are n-hexyl and 2-butyldecyl, respectively. The efficiencies of Y10 and Y11 are both 14%+, which also does not exceed Y5.
These experimental results show that, on the one hand, the "foundation" of Y series materials is relatively good, the average level of efficiency is 12%-14%, while the average level of the previous ITIC series is 10%-12%, and the earlier PDI series , In 6%-8%.
The molecular structure largely determines the upper limit of a material's performance.
On the other hand, it also shows that Y5 has been optimized and more perfect.
If you want to improve it further, you can't "make a little trouble", but need to make greater adjustments to the central unit, such as replacing the NT unit with another unit.
Xu Qiu produced a series of ideas in his mind and handed them to the simulation laboratory to explore on their behalf.
His top priority now is to synthesize the original Y series materials in reality.
Xu Qiu’s target materials are Y3, Y4, Y5 and Y6. The central units of these materials are all of the same kind, with only different end groups, which can be "one pot end", which greatly saves time.
As for Y1 and Y2, he gave up temporarily.
Theoretically, they can also be synthesized, two articles in one section, but it is not necessary.
Even for the four materials Y3-Y6, Xu Qiu does not plan to write too much articles, because now he has only one goal, and that is the CNS main journal.
If you just publish one article every time you optimize it a little bit, the number of articles will be larger. There may be five or six articles at the AM, JACS, EES level, but you may miss the chance to be the top CNS main journal.
This is not only for system tasks, but also for my own research career.
The gold content of a piece of "Nature" is higher than that of ten pieces of AM.
Basically, there is an article of "Nature", and it is a matter of time to rise to the position of "excellent youth" in China.
Therefore, Xu Qiu's plan was to first hold back a wave of big moves, and then directly hit Wang Bo, raising the efficiency to a very high level at one time.
For example, reaching a recognized threshold of 15% in the field of organic photovoltaics, or even breaking this threshold, reaching more than 16%.
Under this circumstance, there is still a good chance of impacting a CNS.
It is conceivable that the colleagues of organic photovoltaics are still working hard for the efficiency to exceed 13% (the "Nature Energy" with an efficiency of 13% has not been published), if it does not take long for an article to directly achieve the efficiency of 15 or 16 %, how shocking that would be.
The specific synthesis scheme planning, because the Y3-Y6 material end group A unit is the ICIN derivative used in the previous ITIC system, so it does not need to be re-synthesized, and the main consideration is the synthesis of the central D unit.
In fact, in a strict sense, the molecular structure of Y series receptors is no longer the ADA structure of the ITIC system.
The nature of the central NT unit is close to the A unit, and the TT units on both sides of the NT are close to the D unit, plus the end group A unit, so the Y series acceptor is actually a molecule with a structure similar to ADADA.
Xu Qiu speculated that the ADDA molecular structure of Y series receptors may be a major reason for its performance surpassing ITIC series materials.
Of course, looking for the reason for the performance improvement is something later, and now we still have to focus on the synthesis of materials.
The synthesis of Y3-Y6 requires six-step reactions, and the first five steps of synthesis are exactly the same, so only one-pot reaction can be used.
In the first step, a dibromo-substituted benzotriazole (NT) unit with an ethylhexyl side chain on the nitrogen atom is connected to the remaining two reaction sites of the benzene ring through a nitration reaction. Group to obtain NT units substituted with dibromo and dinitro groups.
In the second step, the dibromo, dinitro substituted NT and monotrimethyltin substituted TT unit are reacted to obtain the structure of TT-NT-TT, wherein two nitro groups are connected to the NT.
The third step is to reduce the nitro group in the TT-NT-TT molecule and form a ring with the adjacent TT unit to form a cyclic secondary amine (a compound generated by the substitution of two hydrogen atoms on the ammonia molecule with a hydrocarbon group) , A continuous condensed ring structure is obtained, and the conjugation length is 7, that is, seven five-membered and six-membered rings are connected in the form of a condensed ring. At this time, there is a secondary amine between TT and NT in the product, and there is a residual hydrogen atom on it, which is a reaction site.
In the fourth step, the reactants in the third step are reacted with brominated alkanes to replace the hydrogen atoms on the secondary amine with alkyl groups to form tertiary amines, to achieve the purpose of introducing side chains on the N atom, and to obtain the final central DAD unit.
In the fifth step, the aldehyde group reaction of the central DAD unit connects two aldehyde groups at both ends of the central DAD unit.
In the sixth step, the aldehyde-based DAD unit reacts with the unit to obtain Y3-Y6 series acceptor materials.
After preparing for the experiment, Xu Qiu entered the chemical laboratory on the fifth floor of Xiancai, put on protective equipment, and started the experiment.
The first step of the reaction is to carry out a nitration reaction on the NT unit.
The raw materials are dibromo-substituted NT units, nitric acid and trifluoromethanesulfonic acid.
Among them, trifluoromethanesulfonic acid is a new reagent.
It is also known as trifluoromethane sulfonic acid. It is easily soluble in water, has low toxicity and has a wide range of uses. It is one of the strongest organic acids. It is highly corrosive and hygroscopic. It is widely used in medicine and chemical industries.
In terms of molecular structure, trifluoromethanesulfonic acid is a product in which a hydrogen atom in a sulfuric acid molecule is replaced by a trifluoromethyl group, which is more acidic than 100% sulfuric acid.
In many occasions, trifluoromethanesulfonic acid can replace traditional sulfuric acid, hydrochloric acid and other traditional inorganic acids to optimize and improve the process.
Taking into account that the NT unit is relatively cheap, and four materials will be synthesized at the end this time, there is more demand for raw materials. In addition, the photoelectric properties of the Y series materials have been verified by the simulation laboratory. Xu Qiu is also in the simulation experiment. Relevant synthesis experiments were rehearsed in the room, so he decisively carried out large-scale synthesis.
First, take out a washed and dried two-necked flask from the oven.
Then, weigh the reactant NT monomer, 10 g, and put it into the reaction flask.
Then, concentrated nitric acid, 35 ml, into the reaction flask.
Finally, draw 5 ml of trifluoromethanesulfonic acid and add it to the reaction flask.
When adding trifluoromethanesulfonic acid with a disposable dropper, Xu Qiu found that this thing would also smoke in the air like fuming sulfuric acid and fuming nitric acid, probably because it inherited the water absorption of sulfuric acid.
This step of the nitration reaction is not very difficult, because for the dibromo-substituted NT unit, this kind of material with fewer reaction sites may have fewer side reactions.
However, if there are more reaction sites, the nitration reaction is somewhat difficult.
For example, when Xu Qiu was doing 3D-PDI before, he once did a nitration reaction. As a result, several products were directly synthesized, and they could not be separated and purified at all, and the experiment directly failed.
In the evening, Xu Qiu processed the product and purified it with a column method. The yield of this step was very high, reaching 93%.
However, due to time constraints, there is no way to proceed with the second step of the reaction.
The main reason is that there are no beds in Jiangwan to rest, so the experiment must be finished before the last school bus, otherwise, you can only take a taxi or ride a bicycle back to the Handan campus.
The Handan campus and the Jiangwan campus are not far away. If you ride a bicycle, Sun Wo said you can get there in half an hour, but Xu Qiu hasn't tried it, and he doesn't want to try it for the time being.
Sun Wo knew it because he didn't apply for the student dormitory after enrolling, and he still kept the habit of cycling home every day during the summer vacation, and he knew better about riding.
I don't know if Sun Wo is simply trying to save one or two thousand annual accommodation fees, or to exercise, or for other reasons.
On Tuesday, Xu Qiu went to the Jiangwan campus again.
Continue the second step of the reaction to react yesterday's reactant with the TT unit substituted with monotrimethyltin.
This step is the Stille reaction of small molecules. There are not many side reactions. It is only necessary to complete the reaction of all the reactants as much as possible, which is relatively easy.
Therefore, Xu Qiu directly uses the microwave reactor to provide a relatively violent reaction condition, which can increase the yield of the reaction at the same time and shorten the time required for the reaction.
In the afternoon, Xu Qiu got the crude product, filtered, revolved, and passed through the column to obtain an orange-red product with a yield of 82%.
Continue to the third step, which is the reduction of the nitro group.
The purified product in the second step and triethyl phosphate are used, and o-dichlorobenzene is used as the reaction solvent, which needs to be heated and refluxed overnight.
The reaction in this step is not difficult, just add each reagent carefully to the reaction flask, and then set up the equipment.
The only thing worth mentioning is that the new reagent used this time, triethyl phosphate, is a colorless liquid with a low viscosity and a slight fruity scent.
When Xu Qiu was buying medicine, he almost bought triethyl phosphite by mistake.
This is because the English names of Triethylphosphite and Triethylphosphate are so similar, there is only a difference between the letter "i" and "a".
From this point of view, the Chinese drug name is still relatively advantageous. With the addition of the word "亚", the difference between the two can be seen at a glance.
It’s no wonder that the Histochemical Abstracts Service (CAS), a subsidiary of the National Chemical Society, will introduce CAS numbers to distinguish different substances. Otherwise, based on the similarity of the English names, when using other drugs, it is estimated that many people will mistake.
The point is that for chemical reagents, the difference is far from perfect.
Regardless of the difference between triethyl phosphite and triethyl phosphate, the molecular structure is only that the latter has one more phosphorus-oxygen double bond than the former, and the difference in physical and chemical properties will be very large.
For example, triethyl phosphate can be completely soluble in water, while triethyl phosphite is almost insoluble in water.
On Wednesday, continue the experiment.
Xu Qiu post-processed the product of the third step reaction, and directly removed the solvent by rotary evaporation, and the obtained crude product was used in the fourth step of the reaction.
This step does not need to be purified, because even if there are side reactions and formation of by-products, it will not affect the next experiment, so there is no need to purify.
When doing synthesis in an organic laboratory, try to reduce the experimental steps as much as possible under the precondition of ensuring that the experiment will not fail.
The time saved is very good whether it is to continue experimenting, writing articles, or paddling.
The fourth step of the reaction is to introduce side chains on the secondary amine, and the product of the third step, bromine-substituted ethylhexyl, potassium iodide, potassium carbonate, and DMF solvent are used.
Originally, Xu Qiu chose to use the shorter 2-ethylhexyl group as the side chain, considering that there is already a side chain on the NT unit, and there is no need to use a longer side chain to meet the basic solubility requirements of the material.
Later, the results of Y10 and Y11 also showed that Xu Qiu's original idea was correct.
This reaction needs to react for 10 hours at 90 degrees Celsius and protected from light.
In the evening, Xu Qiu treated the product of this step, extracted with ethyl acetate, washed with water, dried, and passed through the column.
Because the conjugate structure of the material has not changed much, the product obtained is still orange-red.
For organic photovoltaic materials, the main color is the conjugated structure, and the side chain has relatively little effect on the color of the material.
Due to time constraints, Xu Qiu did not have time to vote for the next fifth step.
On Thursday, continue the Jiangwan experiment.
However, today is quite special. Xu Qiu chose this semester's courses on this day.
Early in the morning, he sent an e-mail to several teachers, asking for leave sincerely, saying: "There is an important continuous experiment to be carried out. I hope to ask for a day off and hope for approval."
Speaking of which, Xu Qiu hasn't skipped class very much this semester.
The main reason is that he is now well-known in the department, so that many teachers know him, so he will be especially "cared for" in the classroom, and he is often asked to answer questions.
Xu Qiu didn't dare to skip class as unscrupulously as he did during undergraduate studies, even if these teachers didn't name them.
Regarding the matter of asking for leave, in fact, what most teachers want is an attitude. You don't have to come to class, but you have to tell me to show respect. Few teachers will not approve leave.
Sure enough, not long after Xu Qiu's mail was sent out, at 7 or 8 in the morning, he received an email reply from the teachers, indicating that he was going to leave.
Today is the fifth step of the reaction, that is, the reaction of adding aldehyde groups. Liquid nitrogen is needed to add aldehyde groups to both ends of the central DAD unit.
The reaction is not difficult or troublesome. The main reason is that there is no cryogenic physics laboratory in Jiangwan, and liquid nitrogen needs to be brought from the Handan campus.
With liquid nitrogen, you can’t take a school bus. You can only carry a liquid nitrogen container with liquid nitrogen, and then take a taxi to take the liquid nitrogen there.
Finally, after a day of tossing, in the evening Xu Qiu finally got the reaction product of the fifth step after purification through the column.
Originally put 10 grams of NT raw material, after this step, only 5.35 grams were left.
However, this amount is completely acceptable.
If evenly distributed, each material of Y3-Y6 can be synthesized into more than 1 gram, which is enough for the time being.
After finishing the experiment, Xu Qiu took the school bus back to Handan, dragged his exhausted body back to the dormitory, took a hot bath, and his exhaustion subsided a lot.
Now that I am upgraded to a postgraduate student, I have a 24-hour hot water supply, and finally I don’t need to take a cold shower every day like my undergraduate student.
On Friday morning, Xu Qiu stayed at the Handan campus.
Today, he will perform his duties as a teaching assistant. On the one hand, he will evaluate the PPT speeches of undergraduates in Teacher Wei's course, and on the other hand, he will lead them to visit the laboratory.
Although Xu Qiu hadn't done any of these things before, he had accumulated a wealth of experience in Wei Xingsi's group for more than a year, and it was not difficult for him to deal with such things.
I have to say that working in Wei Xingsi's group is really a lot of things, but it's really training people.
The number of students taking this course is not large, there are only a few, and all of them are present.
Originally, at the beginning of the semester, Teacher Wei wanted to let several undergraduates from the new research group choose his courses.
As a result, when Wei Xingsi told them, the course selection time had passed, and there was no way to modify the class schedule, and finally had to give up.
But they can wait until the next time Wei Xingsi starts to choose. Basically, Wei Xingsi can get an A stably in this course, or at least a B+.
After all, it was Teacher Wei who scored, and he would definitely give a good grade to the students in his group.
Although this is "seeing people to give points", it is unfair, but how to put it, the national conditions are like this.
This is also historical inertia. For example, the remnants of feudalism such as "patriarchy" have not been completely cleaned up until now.
The first is the evaluation of the PPT speech. Xu Qiu didn't bother other people, so he alone pulled these students into the small conference room on the third floor of Caiyi.
In fact, it is relatively easy for him to ask someone to come and help, such as Ramo Wenlin or Han Jiaying.
But firstly, other people are very busy. Two people come to evaluate the work efficiency, which is equivalent to directly halving. Secondly, after all, he has taken a few hundred dollars every month from the school, so he needs to do things with the money.
The latter is also the philosophy of Teacher Wei. For example, when he asked Xu Qiu to review the doctoral dissertation, or the associate professor's conversion materials, he gave Xu Qiu the review fee. His proposition is "Whoever does the job gets the money."
As for Xu Qiu and the others for their help in reviewing the manuscript, there is really no remuneration in kind. After all, reviewing the manuscript itself is voluntary labor.
But from another point of view, the rewards have actually been received, which is relatively false, including articles that are more easily accepted, and less likely to be directly rejected by the editor, and so on.
The students began to report in turn, giving speeches in English.
Some of them have slightly better English, and some of them have a slightly worse English, but generally speaking, they are all okay.
After all, students who have the courage to choose an all-English course usually have two brushes, and Xu Qiu did not choose an all-English course before.
Of course, he did not choose the English course mainly because he was afraid of trouble. For example, the English course taught by foreign teachers in English not only gave poor marks, but also usually had a lot of homework in class. Choosing such a course was purely to find abuse for himself.
When Xu Qiu listened to the reports from the students, he was not idle, doing two purposes at the same time, filling out his teaching assistant manual at the same time.
The teaching assistants in the school will receive a booklet to record the situation in each class, the number of students who should arrive, the actual number of students, and the main content of the course, suggestions for the course, and so on.
However, Xu Qiu has never appeared in class except for the first appearance, and now he can only rely on imagination to complete the teaching assistant manual.
In fact, Xu Qiu is not a special case. Most teaching assistants do this.
Basically, I can see one side at the beginning of the class, and another side when the exam is invigilated. At other times, there is no one.
The main reason is that there is no need to assign teaching assistants to many courses. Even if teaching assistants are assigned, there is no need to sit in the classroom for each class. However, teaching practice such as teaching assistants is a compulsory credit for every graduate student.
It can only be said that many things in the school are very rigid, and there is almost no difference from the training program of professional students. For example, teaching practice must be done, several lectures must be listened to, and reports must be made at conferences above the school level.
It may also be because there are too many graduate students now, and the school is not well managed, so it can only do one size fits all.
And many postgraduates do not go to graduate school for the sake of scientific research, but are employed in graduate school, which means they don’t want to find a job, or can’t find a good job, so they just go to graduate school for two or three years.
This is also a manifestation of the internal scrolls of contemporary college students. It is difficult for fresh graduates to find jobs. Those who have the conditions to go to graduate school naturally tend to change the track. After all, some positions are restricted to graduate students, and there will be more choices after graduate school.
The school's rigid restrictions may also be setting a bottom line so that the masters and doctors trained are not so "ugly", at least they must have some scientific research literacy.
After the students finished their speech, Xu Qiu took the group to Caiyi 216 Lab and visited it.
One of the junior girls said after seeing the laboratory: "The area is so small here that there are so many instruments."
Xu Qiu joked: "Yes, all this is due to the designer of our laboratory, Senior Sister Wu Feifei."
Wu Feifei was experimenting in the glove box. After hearing this, she gave Xu Qiu angrily.
In fact, Xu Qiu is not entirely joking. When Feifei Wu was planning the laboratory, she was stunned by squeezing only about 30 square meters of space into the 60 square meters of ordinary laboratory instruments and equipment, and the space utilization rate. Extremely high.
Lead to the newly purchased instrument later. For example, TRPL can only be placed in Teacher Wei's office.
Compared with the situation Wu Feifei encountered back then, when Xu Qiu later designed the Jiangwan laboratory, it was much simpler, with a large area, and it was willful.
After arranging the group of undergraduates, Xu Qiu went to Jiangwan again in the afternoon to continue the experiment.
Han Jiaying also passed by Xu Qiu. They were separated from each other for several days, and they missed it very much.
When the two arrived at the office on the fourth floor of Xiancai together, the school girl found a hole in the cushion of her own seat. She immediately understood something, and then showed a look of disgust.
Xu Qiu had to smile awkwardly. These days, his experiment is progressing very fast, but most of the time he still spends his time in the office with the code word, "Joule" article, so that's it.
To this end, UU reading www. The two of uukanshu.com "fighted" in the office.
The final solution was that the school girl went to buy a new cushion, and Xu Qiu owned the original cushion.
After the play, the two entered the laboratory and started the final reaction.
Xu Qiu took out 4 grams of the obtained 5.35 grams of central DAD unit, divided into four, 1 gram each, and reacted separately. In the environment of pyridine and chloroform solvents, the mixture was stirred and refluxed overnight to obtain the target product Y3-Y6.
On Saturday, the two continued the liver explosion experiment, and Han Jiaying accompanied Xu Qiu to Jiangwan to deal with the reaction. After four columns, they finally got the four products of Y3-Y6.
After working seven days in a row, with an average working time of 12 hours a day, Xu Qiu said that he was a little bit empty.
Fortunately, the usual physical exercise is not bad, otherwise it may not be able to persist.
Of course, all of this is worth it.
After successfully obtaining four sets of Y series materials, it is time to test the results.