Tian Qing usually likes to travel around, she is also the only one in the group other than Wei Xingsi who has been to the beautiful country before.

Therefore, after Wu Feifei returned from Teacher Wei's office, together with Xu Qiu and Han Jiaying, she asked Tian Qing how to apply for a passport and visa.

Tian Qing talked eloquently: "I applied for a passport and a beautiful country visa more than a year ago when I was on a graduation trip."

"For a passport, I took my ID card directly to the entry-exit management office of the Shanghai Municipal Public Security Bureau, took photos on the spot, filled out the application materials, followed the WeChat public account, and went home to wait."

"After a while, you can check the results on the WeChat public account."

"After confirming that you can get the passport, go to the immigration management office again. You can also bring your ID card and pay a fee of 200 yuan to get the passport."

"Passport processing is relatively fast, usually within a week or two. In addition, I have the impression that the money paid must be in cash."

"In terms of visas, I got a 10-year B1/B2 tourist visa directly. I was lucky and passed it quickly without being checked."

"When you apply at that time, in order to prevent being checked, you still need to reserve some time. At least apply at least one month before departure, so that you don't have to worry about any unexpected events."

"After all, the place to apply for a visa is the Consulate General of the Beautiful Country in Shanghai. They are quite special. They have holidays on weekends and holidays in China, and they also have holidays on holidays in the Beautiful Country. So you know..."

"But don't worry too much. After all, you are invited by the MRS organizer. You have an invitation letter. The probability of successful visa application is relatively high. I will guide you to operate it after your passport is obtained."

"Okay, thank you." Wu Feifei and others agreed one after another. It's good to have a "know-it-all" like Tian Qing in the group.

In fact, Tian Qing knew better than Wei Xingsi about passport and visa matters.

Because Mr. Wei obtained the green card of the beautiful country while working in NREL, but retained the nationality of the flower planter, so he does not need to apply for a visa to go to the beautiful country.

However, the green card is a symbol of permanent residence in the beautiful country. If the green card holder shows the intention to give up the right of residence, for example, if he is not in the beautiful country for 183 consecutive days, or has no tax filing record, the green card may be revoked and withdrawn by the immigration bureau.

Therefore, Wei Xingsi will go to Piaoguo twice a year to check in. Before that, the group did not have any academic achievements, and he has not participated in the MRS conference after returning to China. He usually travels to Piaohua during the winter and summer vacations.

Now, if you can always attend the MRS meeting in the future, you don't have to go twice a year.

After figuring out the matter of going abroad, Xu Qiu opened the application for key projects written by Mr. Wei and checked it.

Wei Xingsi wrote a lot in the introduction part above, and it looks quite exciting.

Xu Qiu didn't expect that Wei Xingsi's ability to write Chinese texts was so strong after staying abroad all year round.

But after thinking about it, Mr. Wei wrote the first notebook after returning to China.

If you don't have two brushes, how can you get millions of start-up funds.

However, for the specific experimental part later, Mr. Wei only briefly wrote about it, and did not expand the description.

Xu Qiu guessed that Teacher Wei probably wanted him to add.

According to the previous plan, this book is roughly divided into three parts. Gong Yuanjiang is responsible for the synthesis of small molecule donor materials, and Wei Xingsi is responsible for the synthesis of polymer donors and non-fullerene acceptor materials.

Therefore, Xu Qiu added some content based on the results of Simulation Lab III these days.

On the one hand, he provided a specific synthesis scheme for non-fullerene acceptors. The A unit is still a derivative of ICIN, and the D unit introduces a nitrogen atom, which is formed on both sides by nitrosation and then reduction to an amino group. A secondary amine connection is formed between two adjacent five-membered rings and six-membered rings, which not only obtains a fused ring structure, but also introduces side chains at the same time, and can also maintain a good packing structure between molecules.

This series of molecules is named Y series molecules, and the device performance of Y1 molecules has reached more than 10%.

On the other hand, for the design of body materials, Xu Qiu decided to work in a simple direction.

The main consideration is that the main light-absorbing substance in the current non-fullerene system is the acceptor, and the donor material may not need to be "too good" to achieve excellent performance.

The structure is still a D-A copolymer, in which one D unit is a simple thiophene unit, and the other A unit is improved based on the same simple BT unit.

The BT unit is benzothiadiazole, fluorine atoms can be introduced on the benzene ring below, and the thiadiazole connected above can be replaced by a six-membered ring, connected by two nitrogen atoms, so that there are two sites on the top, which can be The introduction of alkyl side chains is used to improve its solubility, and Xu Qiu named this kind of donor molecules PTQ series.

It took a lot of energy to perfect the fund book. Xu Qiu had been busy all day, adding three pictures and three paragraphs of text. It was only at night that the work was done and sent to Wei Xingsi by email.

Monday, group meeting.

Xu Qiu's AM article of the IDIC system was published, and he was happy to raise a bonus of 4,000 yuan again.

Before the group meeting started, Wei Xingsi asked, "How are the undergraduates doing?"

Wu Feifei first said: "Yu Ya and Yan Hu are both good."

Han Jiaying and Wu Shengnan then said: "Yin Houlang and Xu Xinjie are also good."

Wei Xingsi nodded, and made a decision: "Then the next group meeting, please inform them to join together. We will hold the group meeting in Caiyi's conference room on the third floor. Let's do this for today. Wu Feifei, please start talking."

Wu Feifei began to report: "It can be seen from the J-V curve that the hysteresis of the two-dimensional perovskite system based on the thienylethylamine organic spacer layer has been significantly suppressed. The current writing progress of the article is about 50%, and it is planned to submit AFM..."

Xu Qiu was thinking to himself, Wu Feifei's system is actually pretty good, but it suffers from low efficiency.

At present, the world record of two-dimensional perovskite in the world has reached more than 15%, but it is still difficult for the group to break through 12%, so the group can only be conservative when submitting articles. If the efficiency can be higher, For example, if it reaches 12% or 13%, there is still a chance to rush to AM.

However, there is no way around this. Wu Feifei and the others have tried very hard to repeat the experiments of several large groups, but they just can't repeat it.

There are many possible reasons, perhaps several leading large groups deliberately or unintentionally concealed the key experimental operation methods, perhaps the organic and perovskite were prepared together in the group, and the solvent vapor used by the organic affected the perovskite device film formation, or other reasons.

Experimental things are often not clear why, the same instrument may be moved to a different place, and the test results will be completely different.

Wu Feifei continued to report: "In addition, after discussions with Xu Qiu last week, the two experimental ideas we got were initially tried."

"One of them is to use the ITIC series of non-fullerene acceptor materials to replace the traditional PCBM and C-60 as the transport layer of the perovskite system. The results seem to be good so far, whether it is a three-dimensional perovskite or a two-dimensional perovskite. In the standard sample system of the mine, the performance of the device has improved slightly, and I plan to explore whether the stability of the device has improved. Theoretically, the stability of the ITIC system is better than that of the PCBM system."

"Another way of thinking is to do the concept of quasi-stacking, that is, to directly spin-coat the organic effective layer on the upper layer of the two-dimensional perovskite. For the time being, it has no effect. It may be necessary to further optimize the processing technology, such as the upper effective layer. The film is thinner."

"That's right, that's right. Everyone remember to communicate with Xu Qiu more often." Wei Xingsi nodded in satisfaction, and he was even thinking in his heart whether Xu Qiu should also be in charge of making perovskite at the same time.

But after thinking about it, forget it. Now there are so many things to do in organic photovoltaics. One person’s energy is always limited, and the current progress in the field of organic photovoltaics is very good. If Xu Qiu is transferred to perovskite Over there, it turns out that the water and soil are not acclimatized, so the gain outweighs the loss.

Duan Yun polished the article for several months, and finally finished it, and first submitted it to ACSAMI to see the situation.

Now Duan Yun is almost in a free-range state. He is mainly writing his graduation thesis, listening to various presentations, spreading his resume widely, and occasionally sharing with Wu Feifei how to use the thermoelectric instrument he built.

It's a pity that Duan Yun's current job hunting process is not very ideal, and there are still zero offers.

Sun Wo has the support of Yu Ya and Yan Hu, and the progress of the experiment has been accelerated. Now the experimental characterization test of the first work has been preliminarily completed, and the article is ready to be compiled.

However, it is sometimes difficult for Sun Wo to even read the literature written by other people, and it is even more difficult to write articles by himself.

This is not entirely Sun Wo's own problem, mainly because the perovskite system lacks the step of material synthesis, and most materials are commercially available, so in the article, the phenomenon of routine is not as common as in the field of organic photovoltaics. Obviously, the difficulty of reading is slightly higher than that of organic photovoltaic articles.

Therefore, Wei Xingsi did not have high requirements for Sun Wo. The first article was practiced and submitted from ACSAMI, the lower limit journal in the group.

Tian Qing continued to sort out the work of "exciton binding energy and exciton diffusion distance of multiple systems", the target journal ACSEL, the progress of the article is about 40%.

Chen Wanqing went to Blue River for three days last week, and the number of times she participated in the lectures was not as active as before.

Wei Xingsi also joked, "You are planning to go directly to Lanhe for an internship."

The senior sister nodded with a smile, and didn't answer the conversation, which was regarded as acquiescing.

Teacher Wei is not disgusted with this. After all, it is something to be happy that his students can find a good job.

However, the flexible, translucent, colorful, scrape coating, and full solution processing system that the senior sister is responsible for is still in the bottleneck, and the device efficiency is stuck at 6.5%.

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