I Have a Research Support System

In the group meeting, the perovskite team first reported.

The efficiency of the two-dimensional perovskite stack device was finally fixed at 10.5%. Wu Feifei began to write an article, the target journal CM, and the current progress is 40%.

For the tin-based two-dimensional perovskite system, Wu Feifei's review proposal has been written and submitted, and the target journal is ACSEL.

Although Sun Wo’s failure of the evaporation equipment last Monday caused that wave of devices to crash, but from Tuesday to Thursday, he made three waves of devices in a row, increasing the device efficiency of tin-based two-dimensional perovskite from 0.00001% to 1 %, increased by a full hundred thousand times!

However, the current 1% efficiency is still far from the 12% efficiency result reported by others in "Science".

At the same time, Sun Wo said: "I think the solvent atmosphere has a great influence on the morphology of tin-based two-dimensional perovskite films..."

Wu Feifei helped to explain: "Before, the glove box was used for the mixture of perovskite and organic. Sun Wo found that the film was often not coated well. Now he has continuously prepared several batches of perovskite devices, and the quality of the film can be clearly seen. The improvement, the efficiency has also been improved at the same time..."

Wei Xingsi thought for a moment, then turned his head and asked, "Xu Qiu, what do you think?"

Xu Qiu has verified through the simulation laboratory before that if organic and perovskite are mixed, the performance of the obtained organic photovoltaic device is at least better than that of pure organic photovoltaic glove box, that is, the glove box at Gong Yuanjiang's side. The device efficiency is lower than 0.3%.

But now there are no conditions in the group, so Xu Qiu and the others usually maintain the solvent atmosphere in the glove box before the experiment to reduce the impact of "mixing devices" on device performance.

Specifically, there are two means of operation, namely, cleaning and regeneration.

For cleaning, it is simply to continuously discharge the gas in the glove box into the atmosphere, and at the same time replenish new nitrogen gas.

This process still consumes nitrogen. A bottle of high-purity nitrogen costs 100 yuan, and it can usually be cleaned for about 30 minutes.

The usual cleaning operation, plus other nitrogen losses, the two glove boxes in the laboratory will generally consume 10 to 20 bottles of high-purity nitrogen in a month.

There are generally two situations where cleaning is used.

One is that air enters the glove box due to broken gloves, improper use of the transfer chamber, overpressure and opening of the protection valve, etc., causing the oxygen content inside the glove box to be too high, such as greater than 100ppm.

This requires a long cleaning, such as five to ten minutes, to reduce the oxygen content in the glove box to tens of ppm, and then let the glove box circulate itself to reduce the oxygen content to a lower level, such as less than 10 ppm.

The other is to clean the device for three to five minutes before preparing the effective spin-coated layer to "change the blood" of the gas inside the glove box in order to obtain a relatively pure nitrogen atmosphere.

This approach has some effect, but it is a temporary solution, not a permanent cure.

Because as the glove box is used longer, many organic solvents will be adsorbed on various surfaces in the glove box, such as the filter screen, and simple cleaning and ventilation are not enough to remove them.

The phenomenon shown is that the glove box has been used for a long time, and the oxygen content will remain above 10ppm, which cannot be automatically reduced to less than 0.1ppm by its own circulation function.

At this time, the method of regeneration is used to "revitalize" the glove box.

The specific method adopted is to heat the place in the glove box where the organic solvent is easily adsorbed, so that the solvent molecules are desorbed at high temperature.

In addition, a nitrogen-hydrogen mixture with a volume fraction of 95%+5% is also used to provide a reducing atmosphere.

The regeneration process generally lasts for up to 24 hours, and cannot be interrupted midway, nor can experiments be carried out.

It can be considered that regeneration is a powerful cleaning process.

During this process, the organic solvent molecules accumulated in the box will be excluded from the glove box, most of them will be directly discharged into the atmosphere, and a small part will remain in the laboratory.

Therefore, the smell in the laboratory during this period will be very difficult to describe. Wearing a gas mask, you can smell a "astringent" smell of chlorobenzene, DMF and the like.

For this reason, the regeneration time is generally scheduled on Saturday when there is no one around.

In addition, after the regeneration is over, the circulation system of the glove box needs to be opened in time, so a special person is required to come and restart the glove box.

It just so happens that if it is scheduled to regenerate on Saturday, it can be used when you come over on Sunday and start it directly.

Of course, there is a limit to regeneration, and it is impossible to completely restore the state of the glove box.

After all, there are various solvents and reagent bottles in the glove box, and organic solvent vapors are volatilizing all the time.

But in any case, the effect of regeneration is much stronger than cleaning.

Generally, glove boxes that often use organic solvents can be used continuously for two or three months after a regeneration.

And glove boxes such as evaporation glove boxes that hardly use organic solvents can be regenerated once a year.

Xu Qiu thought about it and said: "The atmosphere in the glove box will indeed affect the device results. I also think it is better to prepare the organic and perovskite devices separately, but this requires moving the laboratory to Jiangxi Province. bend over..."

"It's not impossible to move to the bend of the river..." Wei Xingsi thought about it for a while, and said, "Either our laboratory in Handan will move during the winter vacation? It mainly depends on the current situation of your stacked device, Xu Qiu. If you can Submit the article before the winter vacation, and we can plan the winter vacation move..."

Wei Xingsi paused, and suddenly asked: "By the way, Xu Qiu, what's the latest progress of your laminated device?"

Xu Qiu looked at Duan Yun, Tian Qing, and Chen Wanqing, the three paddling monsters, and decided to advance the order of his reports, so he replied "It's okay", then inserted the U disk into the computer and started reporting.

He only made one page of PPT this week. The main content is the J-V curve and EQE curve he tested with his schoolmate last Friday, as well as the photoelectric performance parameter table of the best stacked device.

Xu Qiu went straight to the point and said, "Last week, Han Jiaying and I achieved a maximum efficiency of 16.15%!"

Hearing this result, everyone's eyes brightened.

The one who reacted the most was Mo Wenlin, she was thinking in her heart:

"They seem to have made a batch of devices last week, and that's 16%... Hey, my 15.5% has not been warmed up yet, and it has been surpassed, huh."

Wei Xingsi was still debating whether or not to move, and when to move, but now that he heard the result, he instantly laughed like a chrysanthemum.

He didn't expect that just after the New Year's Day holiday, it would usher in a good start.

Xu Qiu ignored everyone's reactions and calmly reported:

"The method we adopted this time is to use a new acceptor material, COi8DFIC, to replace the IEICO-4F in the previous top cell, and keep other conditions unchanged..."

Hearing this, Chen Wanqing frowned, her own IEICO-4F was just abandoned.

But this is also normal. My own IEICO-4F is the earliest near-infrared non-fullerene acceptor.

Later, my main energy was devoted to working for Blue River Company, and I didn't further develop new materials, so it was normal for me to be surpassed by others.

Xu Qiu continued to report: "At the same time, we also found that after the device is prepared, storing the device in the vacuum environment in the evaporation chamber for a certain period of time may improve the performance of the device."

"However, the universality of this phenomenon requires further research."

Although Xu Qiu has already reached a preliminary conclusion in the simulation laboratory, he cannot express it at this stage.

Tian Qing was originally wandering, but when she heard the familiar method of "vacuum placement", she immediately shifted her attention.

Her facial expressions are also very rich, as if she was talking to Xu Qiu from a distance: "Look, I said that my previous discovery is correct, and you all don't believe it."

Although Tian Qing has been engaged in the research of device mechanism for a long time, in the early stage, he would do it himself and make some standard sample system devices.

Her discovery was based on the previous P3HT standard sample system, but it was not taken seriously at that time.

Of course, objectively, this is also related to the fact that the operation of "vacuum placement" is relatively unstable, sometimes ineffective, and more time-consuming.

From Xu Qiu's point of view, he can explore several systems in batches, use a large number of experimental samples, get a broad conclusion, and then decide his next countermeasure based on this conclusion, whether to use this method or not.

For Chen Wanqing and Wu Feifei before, they only had one or two systems in their hands, and it was difficult to find out the rules. When they found that a method was not so stable and it was time-consuming, they would naturally not invest in it. Too much energy to research.

Only Tian Qing, who is relatively salty, has been using this method.

After reporting the results of this device, Xu Qiu began to look forward:

"Next, I plan to further optimize, on the one hand, to continue to explore the impact of 'vacuum placement' time on device performance."

"On the other hand, referring to the article on the ternary system by Li Dan's research group of the National Nano Science and Technology Center, the PCBM originally used for the bottom battery is introduced into the top battery to build a binary IDIC-M/ternary COi8DFIC system , in order to achieve further improvement in device performance..."

Wei Xingsi waited until Xu Qiu had finished speaking, and then said: "16.15%! The job is very good!"

Originally, when he first heard the 16% efficiency result, he planned to ask Mo Wenlin or someone to send samples to NIM for testing.

But when he heard the latter, he was not in a hurry to express his opinion, because Wei Xingsi heard the possibility of hitting 17% from Xu Qiu's confident words.

The previous 15% efficiency to vote for "Science" has about 20 to 30% probability of being accepted, and now 16% to submit, there may be 70% to 80% probability of winning. If it can reach 17%, the probability of winning can be increased to More than 90%.

In the face of unknown, potentially greater opportunities, people are usually used to waiting a little longer.

Just like stocks and funds, when you start to lose money, you always feel that you can get back your money in a few days, and then you can make more money when you get back your money, and if you make some money, you can continue to think about making more.

At this time, a wave of sudden stops came, and it fell by five points. I thought to myself that this must be a short-term adjustment, and I wanted to increase my position.

As a result, it fell another five points the next day. This time, I thought about value investing in my heart. There are always fluctuations in the short term, but I am optimistic about the long term, so I continued to increase my position.

On the third day, it really rebounded and rose by three points. I recognized my value investment and short-term adjustment ideas very much in my heart, and felt that the rise would continue, so I continued to chase the rise and increase my position.

Then on the fourth day, it fell by another four points. At this time, I began to hesitate in my heart, thinking that it would not fall further. I should stop the loss in time and clear the position.

As a result, the warehouse had just been cleared, and the market had just opened on the fifth day, and the daily limit was directly sealed...

It seems that there is a pair of invisible eyes watching your operation.

Wei Xingsi just asked casually before, but he didn't expect to "catch a big fish", so excited that he forgot the moving thing he was discussing.

Therefore, Xu Qiu reminded: "I think this job can be done before the winter vacation, so I can plan to move during the winter vacation."

"Oh, moving, right..." Wei Xingsi came to his senses, thought for a while and said:

"Then I'll talk to the glove box about returning to the factory for remodeling. They said that the remodeling period is within one month. I'll say hello to their boss and try to shorten it to two weeks..."

"In addition, Handan's laboratory has a relatively heavy evaporation equipment, which may be troublesome to move. Let me discuss this with the department and find a professional moving company..."

"Also, the dormitory issue. I'll apply with the department at that time to see if I can arrange you to the Jiangwan dormitory at the same time. But this may be more difficult. I'll think of a way..."

"Finally, the issue of re-optimizing the experimental parameters, let's talk about it when we move over. Anyway, we have to be prepared to stop working for a month or two, so it's best to finish all the experiments that need to be processed... ..."

After talking about the move, Wei Xingsi switched the topic back: "Xu Qiu, continue to optimize according to your ideas, and see if you can improve the performance of the laminated device. Now that the "Science" article has been written, it's just a matter of time." Efficiency data..."

Wei Xingsi thought for a moment, and then made a final decision: "The time is set before the winter vacation. We submit this "Science" article, and then we can achieve as much efficiency as possible."

"Okay." Xu Qiu nodded in agreement, if he really can't reach 17% within a month, then he can only give up temporarily.

Otherwise, if others achieve 15% or even higher efficiency after a while, their own advantages will be greatly squeezed.

Xu Qiu reported to the group meeting in advance that he skipped three water paddle monsters, Duan Yun, Tian Qing and Chen Wanqing.

In fact, they just don't have much PPT to talk about.

Last week, Duan Yun finally chose Warwick, a few days before the expiry of Warwick’s offer, which is not an IT position, so the salary is not high. The monthly salary is 16K, 14 salary. Internship there.

Tian Qing's "Research on Charge Transport Related to Stacked Devices" officially started work, but due to the approaching holiday, she was not very interested in doing experiments, and there was no substantial progress.

In order to "properly paddling", Tian Qing took the initiative to find Xu Qiu last week, saying that "I want to contribute my modest strength to the "Science" article in the group."

Translated, it means "I will help you edit the picture, you add me to the list of authors, and then help with Teacher Wei's side."

Xu Qiu did not refuse. Periodicals like "Nature" and "Science" also have very high requirements for pictures. If you have a professional artist to help you retouch the pictures, you can add a lot to your work and slightly improve the final draft. Rate.

He added Tian Qing's name to the fifth place in the "Science" article, ranking behind Han Jiaying, and moved the positions of two undergraduates, senior sister, Gong Yuanjiang and Wei Xingsi one place back.

Like the previous "Nature·Energy" article, the current "Science" article also has ten authors.

Chen Wanqing also did not report and paddled in the water.

It stands to reason that Duan Yun and Chen Wanqing, who are about to graduate, do not need to attend the group meeting.

However, Wei Xingsi was quite stubborn about this aspect, and made it clear that you don't have to come normally, but you must be present at the group meeting.

Next, Han Jiaying began to report that her PTQ1 work had already begun to write articles, and the target journal AM also planned to submit the article before the holiday.

She is now in the second semester of her senior year. Since she has almost finished her courses and there is no pressure on the exam, she can devote her main energy to scientific research.

Wu Shengnan continued the previous work of Xu Qiu's Y1-Y4 series of materials. While helping Xu Qiu with characterization experiments, he started to synthesize. The target products are Y5, Y6, and Y7.

Xu Qiu saw that the system Wu Shengnan chose was partly a system that he had already done in the simulation laboratory before, but did not make a breakthrough.

However, it's not easy for Xu Qiu to remind him, he can't say that he can predict the future.

Moreover, these systems are quite good once they are done. No matter how good or bad the performance is, after all, these tasks still need to be done by someone.

It's just that Xu Qiu's current goal is to attack the CNS, so he gave up such leftover work.

For the Y series materials, even if they are leftover materials, it is not difficult to post a few AM articles.

After all, the efficiency is there. The efficiency of single-junction devices exceeds 14%, and no one can beat it at this stage.

Mo Wenlin was busy with exams last week, because there were two consecutive exams, so she paddled for a week in experiments.

Several undergraduates did not come to the group meeting, and their academic pressure in their sophomore and junior years is indeed not small.

The newcomer, Fan Wentang, ran over on Monday.

However, Wei Xingsi did not take the initiative to ask him to attend the group meeting, and Fan Wentang wisely did not offer to attend.

After all, now is also a period of mutual inspection between students and tutors, and it is not suitable for too much participation in various things of the research group.

Especially now is the critical period when the group is attacking "Science", so it is still necessary to avoid suspicion.

In the next few days, Xu Qiu continued to revise the "Science" article while preparing stacked devices.

To be precise, it is to watch other people make stacked devices.

The experimenter changed from the former school girl to Mo Wenlin, who was relieved because the latter had already passed the exam.

And after the school girl changed her taste and made a batch of devices, she returned to writing articles on her PTQ series for body work.

The main reason is that after Xu Qiu came to the experimental conclusion of "vacuum placement", the influence of the experimenter was basically eliminated, so the school girl was not asked to continue to make devices repeatedly.

This week, Xu Qiu has the last exam, which requires an open-book exam and a PPT speech at the same time. The type is similar to the previous "Inorganic Functional Materials" and "Composite Materials", and he thinks he can easily pass it.

Xu Qiu estimated that his three professional courses this semester would most likely be A's, plus one exempted English course, and one "Laboratory Safety Education" with a P (pass).

All in all, a full score of more than 10 credits is still very powerful.

Of course, this is mainly related to the relatively "pure" course arrangement during the postgraduate period, most of which are professional courses.

When I was an undergraduate, there were many political courses and general elective courses mixed in the curriculum.

In these courses, you need to compete with liberal arts students.

And Xu Qiu really couldn't compete with their liberal arts students, so he got a lot of B and B+, and his GPA was pulled to 3.5.

The reason why the PK is not good is because the liberal arts students, such as international economics and trade majors, have very few places in the graduate school, and the volume is very large.

Those with a GPA of 3.6 or above are at the bottom of the research team.

Therefore, they strive to get an A in every class.

The material department requires a GPA of 2.8. When actually admitted, the GPA requirement is about 3, that is, students with an average grade of B can be guaranteed.

Because there are many B+ unlimited courses, even if none of the courses can get an A, as long as it is not too far-fetched, if you want to keep the graduate school, you can get it.

Of course, due to the existence of involution, the research threshold of the material department will also become higher and higher.

It is said that in the previous session, that is, Tian Qing's time, 2.8 was able to get in, and now Xu Qiu has already got 3.0 in this session, and after that, it may take 3.2, 3.4... to be able to get in.

In addition to the exams of his own courses, Xu Qiu also has the status of a teaching assistant this semester, and needs to invigilate the exams during the exam week.

Generally, teaching assistants will participate in the invigilation of the courses they are in charge of, but Wei Xingsi's course has no exams, so Xu Qiu was assigned to other courses.

It is another undergraduate course called "Intelligent Materials", a closed-book exam, and the place is in the west auxiliary building of the Twin Towers.

Xu Qiu came to the classroom ten minutes before the appointed time for the exam. Almost all the candidates here had already arrived, and the teacher was already standing on the podium with a stack of test papers in his hand.

The teacher of this course is Wang Jizeng, an associate professor of Qingjiao. He doesn't have a high sense of presence in the department. He is young, about thirty years old, but his hair is already a little thinning.

Wang Jizeng and Xu Qiu nodded in a friendly manner and didn't have much to say.

The invigilation within this kind of department is relatively casual and not too strict.

Cheating naturally exists.

Every year, there are people in the Shanghai Comprehensive University who are caught cheating and punished. Basically, they stay on campus for probation, and some are even expelled.

Before, there was a girl who helped her boyfriend take the high math exam, but she was caught. Both the girl and her boyfriend were fired, emmm...

It is said that the girl's parents came over and cried, but it was of no use.

Because they were caught and regarded as typical at that time, the punishment was very severe.

This is the same as the country's crackdown. If you commit a crime during normal times, if you have a minor problem, you will be released after a few days. During the crackdown period, you will be dealt with severely.

It just happened to catch up, it can only be said that it was bad luck.

Because of this kind of thing, those who are exposed are only the tip of the iceberg, and those who are not exposed are the majority.

At least during the previous exams, Xu Qiu, as an examinee, saw students cheating no less than ten times.

Once someone was arrested on the spot, but the teacher just confiscated the other party's tools for committing the crime and did not pursue it.

Most teachers are still relatively "kind".

The bell rang and the exam began.

Perhaps because the twin buildings are used for both office and teaching, there is no bell used like the second, third, and fourth teachings, but a melodious bell.

After Xu Qiu helped Wang Jizeng distribute the test papers, he found a seat in the back row and sat down, and didn't plan to go out to make inspections.

Wang Jizeng sat on the podium.

Invigilation is quite boring, because you can only sit for a long time, and in principle, you can't play with your mobile phone.

Before, Xu Qiu also saw a teaching assistant ask the teacher for a set of papers because he was too bored, and started to do it by himself...

However, Xu Qiu has a way to pass the time. He directly entered the simulation laboratory to check the results of the past few days of exploration.

PS: Yesterday the number of monthly tickets actually reached 2200+, book friends are really awesome! thanks for your support!

PS2: New April, set sail, everyone has so many monthly passes in stock at the end of the month, they must have guaranteed monthly passes... Please ask for guaranteed monthly passes...