I Have a Research Support System

Wednesday, May 5th.

Although it was only in the afternoon that they started working normally, Xu Qiu, Han Jiaying and Chen Wanqing made an appointment to meet at Caiyi 216 at ten in the morning. They planned to have a small meeting to discuss the future work prospects of the ADA non-fullerene system. Let’s do it by the way Group meeting PPT.

When Xu Qiu and Han Jiaying arrived at Caiyi as scheduled, they found that the doors of rooms 216 and 218 were ajar, indicating that there were people inside.

The person in Room 218 must be Mr. Wei, which is not surprising, you can usually meet him in the office on Saturdays; and the people in Room 216 are not Senior Chen Wanqing who came earlier, but Wu Feifei and Wu Shengnan.

Wu Feifei is sorting out the test data of last week, the production team will meet the PPT, and Wu Shengnan is writing a review proposal on "Perovskite Quantum Dot Luminescent Materials". Higher, the work that she did not finish before the holiday has to be completed during the holiday.

A few minutes later, Chen Wanqing pushed the door open and walked in. Seeing the crowds of people in Room 216, she was taken aback, "Why are there so many people?"

"They are also like us. They came to work early." Xu Qiu smiled and explained to the senior sister, and then suggested: "Let's go to the small meeting room on the third floor to discuss."

"Okay." The seniors and the juniors agreed one after another.

Xu Qiu went to the concierge to get the key, and opened the door of the meeting room on the third floor. The senior sister was the lecturer, holding a laptop, and the junior sister was in charge of recording, holding an experiment notebook and a black fountain pen.

The three got together and sat down facing the computer screen. Xu Qiu coughed lightly and said, "Let's get started."

Chen Wanqing nodded, opened the PPT file, pressed F5 to enter the screening mode, and talked eloquently: "The current IDT-ICIN, an ADA-type non-fullerene acceptor molecule, has the D unit as IDT and the A unit as ICIN, based on There are four optimization schemes for this molecule."

"The first one is to regulate the linear conjugation length of the D-unit IDT. The current number of fused rings is five, of which there is a benzene ring in the center and two five-membered rings on each side. It can be achieved by introducing new conjugated fused rings. structure, increase the number of fused rings to 7, 9, or even more..."

"The second is to change the D unit and the side chain of IDT. The current side chain is a six-membered ring phenyl side chain substituted with four hexyl groups, which can be replaced by straight chain, branched chain alkyl, or thiophene ring side chain, etc. ..."

"The third is to optimize the structure of the A unit. There are four reaction sites on the benzene ring of ICIN, and one or two groups are introduced into it to generate a mono-substituted or di-substituted ICIN structure. It can be done Halogen atoms such as fluorine atoms and chlorine atoms are introduced to further improve the electron-absorbing ability of the ICIN unit, and electron-donating groups such as methyl and alkoxy groups can also be introduced to suppress the overall electron-absorbing ability of the A unit..."

"The fourth is to imitate the article in "Nature Materials" and synthesize a structure similar to IDTBR molecules, that is, to introduce a small conjugated unit between the D/A units of ADA, which can be the BT unit they used , it can also be a thiophene unit and so on..."

After the senior sister introduced the four ideas, she stopped abruptly.

"It's gone?" Xu Qiu asked suspiciously: "What about the specific synthetic route, is there only one page of PPT?"

"Well, there's only one page, and the synthesis route hasn't been figured out yet." Chen Wanqing added weakly: "Aren't we discussing this?"

"Okay." Xu Qiu understood the intention of the senior sister. Now the senior sister has listed all the possible research directions in a large and comprehensive way, and wants to choose some for her.

"If you don't consider the strategy of greatly modifying the D/A unit, the summary is fairly comprehensive." Xu Qiu summed it up, then pondered for a moment, and analyzed:

"The first and third methods have relatively large changes to the molecular structure, and the fluctuation range of device performance should be relatively large. There is a high probability of achieving a breakthrough in efficiency, but the difficulty of synthesis is also relatively high. At least there is no way to see it at a glance. To find out the detailed synthetic route, we still need to read some literatures.

The second path is relatively simple. IDT units with different side chains can be purchased directly from the optoelectronic company in Shencheng. At the same time, it is not difficult to synthesize them by yourself. Positive fluctuations are still relatively difficult, and the high probability can only increase by a few tenths or a percentage point.

The fourth method, referring to the results of the "Nature·Materials" article, the synthesis route is better designed, you can imitate it first, and you can also cross over in the afternoon group meeting. As for the impact of this strategy on molecular performance, it is still impossible to estimate. After all, they only made IDT-2BR, and there is no IDT-2R structure as a control group. "

Han Jiaying, who had been busy taking minutes of the meeting, suddenly interrupted: "Brother, what you mean is that the first and third strategies are easier to achieve a breakthrough, the fourth strategy is unknown, and the second strategy is suitable for icing on the cake, is that right? ?”

"Well, that's pretty much what it means." Xu Qiu agreed.

"Hmm..." Chen Wanqing thought about it for a moment, and said, "Anyway, I can't do all these directions by myself, so I'll start with the fourth one."

"Okay, after I'm done with my graduation project and the B3T-6 series of articles about my school girl, I'll choose a direction to start from..." Xu Qiu paused, then shook his head and said, "Forget it, let's do it again." There is a month to graduate and defend, I'd better call you for assistance first, there must be a lot of things to deal with at the Handan campus when graduation is approaching, and the laboratory is in Zhangjiang, which is too inconvenient."

Han Jiaying answered at the right time: "Brother, before graduation defense, you stayed in Handan to help us make devices. By the way, what system will I do in the future?"

Xu Qiu rubbed his chin, thought for a while, and said, "Sister, you can synthesize the donor, it can be based on the current FTAZ wide bandgap material.

FTAZ is a D-A copolymer, the name of the A unit used is FTAZ, and the center is a derivative of the BT unit substituted by difluorine. The sulfur atom on the BT thiadiazole is replaced by a nitrogen atom with an alkyl side chain. The scientific name is roughly is difluorobenzotriazole with two thiophene units attached to it;

D unit is a common BDT unit, but the side chain is special, it is an alkyl straight chain, you can try to use other types of side chains, including alkoxy side chains, alkylthiophene side chains, etc. The monomer can be purchased directly from Shencheng You can buy it from that company, or you can synthesize it yourself. I have summarized the literature in this regard.

In addition, in order to be different from others, you can use your own set of naming methods, how about starting with H1? "

"Okay." Han Jiaying nodded and said: "In addition, I noticed that there is a type of A structural unit called BDB in the literature, which is used to synthesize D-A copolymer donor materials with wide band gaps, and the synthesis is not very difficult. , I want to try it."

Later, the school girl drew the molecular structure of BDD by hand in the experiment notebook: "It looks like this, a bit like a person lifting weights..."

"Well, this molecular structure is a bit strange..." Xu Qiu recalled for a few seconds, and said, "It seems that the donor material is called PBDB-T, and the device efficiency of the blend with PCBM is about 5%."

"That's right, it's PBDB-T," Han Jiaying praised, "Brother, your memory is really good."

"Basic operation," Xu Qiu waved his hand, and then said: "This system can also be done. The more types of donors and receptors we can get, the easier it is to achieve breakthroughs in device performance."

When Xu Qiu and the others finished discussing and returned to 216, Wu Feifei had disappeared, Wu Shengnan was still reviewing the proposal, and Duan Yun, Tian Qing, and Sun Wo didn't show up.

Wei Xingsi had also left, Xu Qiu felt a little regretful, and originally wanted to make a face with Teacher Wei.

...

In the afternoon, no one was late, and even Tian Qing showed up at the door of the laboratory at 1:28 on a rare occasion.

At 1:35, Wei Xingsi summoned the eight members of the research group to Room 218. When everyone arrived, he sat at the desk, glanced at everyone, then knocked on the table, and said: "The group meeting begins. Come on, Wu Feifei, come first."

Wu Feifei opened the PPT and showed the experimental results last week, first of all, the J-V curve and photoelectric performance parameters of the two-dimensional perovskite device.

"Currently, the n-butylamine system has been optimized to 10%, which is very close to the 12.4% efficiency in the literature, and the isobutylamine system developed by ourselves has a maximum efficiency of more than 7%..."

"7%, 7%," Wei Xingsi repeated twice, then stared at the projection screen for a while, and then said: "This efficiency value is good, Wu Feifei, you and Sun Wo can continue to optimize the device while you can start Measure various characterization tests, such as XRD, SEM, etc. For the new field of 2D perovskite, the most important thing now is time. Our work must be fast and published before other groups. It’s okay to be lower.”

Wei Xingsi pointed to a stack of unbound documents on the desk next to him, and said, "I just took a vacation, and within a few days, I saw three articles on two-dimensional perovskite in the morning, come here after you finish the lectures." Get it sorted out."

"Okay." Wu Feifei responded, operated the laser pointer and continued to introduce: "This is a set of pictures of two-dimensional perovskite films I took with my mobile phone. I placed them in the air environment, and they can maintain a dozen Hours don't change color..."

The perovskite photovoltaic material as the active layer, which is normally brown in color, can achieve broad light absorption in the visible range. However, if it is a three-dimensional perovskite material, it will quickly decompose and deteriorate after encountering water and oxygen in the air, turning into a yellow film, which is the color of the decomposition product lead iodide. The stability of the two-dimensional perovskite material in front of me has improved a lot. After more than ten hours, it is still a brown device.

"Well, the idea of ​​taking pictures is good, and the comparison is indeed very obvious." Wei Xingsi nodded, and added: "It's a bit rough, it's better to keep the temperature and relative humidity consistent every time you do a stability test, so that you can compare Rigorous. I used a constant temperature and humidity chamber when I was abroad, and our group can buy one, and we don’t need to choose one that is too expensive, as long as it has basic functions.”

Wu Feifei answered: "I have browsed the manufacturers of constant temperature and humidity chambers before, and finally found a local company in Shanghai. More than 3,000 yuan."

Wei Xingsi didn't hesitate much, and made a decision directly: "This is fine, you can just contact them directly to buy, remember to issue an invoice."

Later, Teacher Wei looked at Xu Qiu, Chen Wanqing and Han Jiaying, and said, "It is still necessary to buy a constant temperature and humidity chamber. They can also be used after making organic ones. The air stability of non-fullerene materials not bad."