Chapter 274: This molecular structure is a bit strange

May 5th, Wednesday.
Although they started to work normally in the afternoon, Xu Qiu, Han Jiaying and Chen Wanqing had arranged to meet at Caiyi 216 at 10 am. They planned to hold a small meeting to discuss the future prospects of the ADA non-fullerene system. Group meeting PPT.
　　 When Xu Qiu and Han Jiaying arrived at Caiyi as scheduled, they found that the door of the room was hidden, indicating that there were people inside.
　　 218 must be Teacher Wei. This is not surprising. You can usually meet him in the office on Saturdays. The people in room 216 are not the senior sister Chen Wanqing who came here in advance, but Feifei Wu and Shengnan Wu.
Feifei Wu is collating the test data of last week, and the production team will make PPT, while Wu Shengnan is writing a review plan on "Perovskite Quantum Dot Luminescent Materials". For postgraduates who receive monthly salary, Mr. Wei's requirements are more Higher, she has to make up for the work she did not finish before the holiday.
　　 A few minutes later, Chen Wanqing opened the door and walked in, looking at the crowds in Room 216, she was also taken aback, "How come there are so many people."
　　 "They came over to work ahead of time just like us," Xu Qiu smiled for the senior sister, and then proposed: "Let's go to the small conference room on the third floor to discuss."
　　 "Okay." The school sister and the school girl agreed.
　　 Xu Qiu took the key from the concierge and opened the door of the meeting room on the third floor. The senior sister was the speaker, holding the laptop, and the senior sister was in charge of recording, holding the experiment notebook and black pen.
　　 The three of them got together and sat down in front of the computer screen. Xu Qiu gave a light cough and said, "Go ahead."
Chen Wanqing nodded, opened the PPT file, pressed F5 to enter the screening mode, and talked freely: "The current type of non-fullerene receptor molecule, the D unit is IDT, and the A unit is ICIN. Based on this molecule, next There are four optimization schemes."
"The first one is to control the linear conjugation length of the IDT of the D unit. The current number of fused rings is 5, of which, the center is a benzene ring, and there are two five-membered rings on each side. New conjugated fused rings can be introduced. Structure, increase the number of fused rings to 7, 9, or even more..."
"The second kind is to change the D unit, the side chain of IDT. The current side chain is a six-membered phenyl side chain substituted by 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. It should be relatively easy to introduce one or two groups to generate a mono- or di-substituted ICIN structure. Introduce halogen atoms such as fluorine and chlorine atoms to further improve the electron-withdrawing ability of ICIN units. It is also possible to introduce electron-donating groups such as methyl and alkoxy groups to inhibit the overall electron-withdrawing ability of A unit..."
"The fourth is to imitate the article in "Nature·Materials" and synthesize a structure similar to the IDTBR molecule, that is, to introduce a small conjugate unit between the D/A units of ADA, which can be the BT unit they used. , It can also be a thiophene unit, etc..."
After 　　 senior sister introduced the four ideas, she stopped abruptly.
　　 "It's gone?" Xu Qiu asked puzzledly: "What about the specific synthesis route, is there only one page of PPT?"
　　 "Well, there is only one page, the synthesis route has not been figured out yet." Chen Wan added weakly: "We are not discussing."
　　 "Okay." Xu Qiu understood the intentions of the senior sister. Now the senior sister has listed all possible research directions in a comprehensive and comprehensive way, and wants to choose a few for her.
　　 "If you don't consider the strategy of drastically revising the D/A unit, the summary is quite comprehensive." Xu Qiu summed up, then pondered for a moment, and analyzed:
"The first and third methods have relatively large changes to the molecular structure, and the device performance should have a relatively large fluctuation range, and there is a higher probability of achieving a breakthrough in efficiency, but the synthesis is also relatively difficult, at least there is no way to see at a glance. To come up with a detailed synthesis path, you still need to read some documents.
The second path is relatively simple. IDT units with different side chains can be purchased directly from the photoelectric company in Shenzhen, and it is not difficult to synthesize by yourself. However, just modify the side chain of D unit to make the efficiency greatly Positive fluctuations are still relatively difficult, and the probability can only increase by a few tenths or one percentage point.
　　 The fourth method, referring to the results of the article "Nature·Materials", the synthesis route is better designed, you can imitate it first, and you can also make a difference in the afternoon group meeting. As for the impact of this strategy on molecular performance, it is still incalculable. After all, they only made IDT-2BR, without the structure of IDT-2R as a control group. "
Han Jiaying, who has been busy taking minutes of the meeting, suddenly interjected: "Brother means that the first and third strategies are easier to make breakthroughs. The situation of the fourth strategy is unknown, and the second strategy is suitable for icing on the cake. Is that true? ?"
　　 "Well, that's almost what it means." Xu Qiuying said in peace.
　　 "Hmm..." Chen Wanqing considered for a moment, and said, "Anyway, I can't finish it by myself in so many directions. I'll start with the fourth one."
"Yes, after I am busy with the B3T-6 series of articles on design and school girl, I will also choose a direction to start..." Xu Qiu paused, shook his head and said, "Forget it. I’ll be graduating and defending in one month. I’ll give you some support first. There must be a lot of things to be handled on the Handan campus near graduation, and the laboratory is in Zhangjiang, which is too inconvenient."
　　Han Jiaying answered at the right time: "Senior brother stayed in Handan to help us make devices before graduation. By the way, what system will I do next?"
　　 Xu Qiu touched his chin, considered for a while, and said, "Senior girl, you can synthesize the donor body. It can be based on the current FTAZ wide band gap material.
Copolymer, the name of the A unit used is called FTAZ, and the center is a derivative of the BT unit substituted by difluoro. The sulfur atom on the BT thiadiazole is replaced by a nitrogen atom with an alkyl side chain. The scientific name is roughly difluoro Substitute benzotriazole, and connect two thiophene units next to it;
The D unit is a common BDT unit, but the side chain is quite special, it is an alkyl straight chain, you can try other side chain types, including alkoxy side chain, alkyl thiophene side chain, etc., the monomer can be directly from Shencheng It can be purchased by that company, or it can be synthesized by itself. I have summarized the literature in this area.
　　 In addition, in order to be different from others, you can use your own set of naming methods, why not start with H1? "
"Alright." 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 wide band gap DA copolymer donor materials, and the synthesis is not difficult. , I want to try it."
　　 Then, the school girl hand-painted the molecular structure of BDD on the experimental notebook: "It looks almost 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 efficiency of the device blended with PCBM is about 5%."
　　 "That's right, it is 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 returned to 216 after discussing, Wu Feifei was no longer visible. Wu Shengnan was still in the liver review plan, and Duan Yun, Tian Qing, and Sun Wo did not appear.
　　 Wei Xingsi has also left, and Xu Qiu feels a little regretful, and originally wanted to brush his face with Teacher Wei.
　　……
　　 In the afternoon, everyone was not late, and even Tian Qing appeared at the entrance of the laboratory when he was stuck at 1.28.
At 1:35, Wei Xingsi summoned the eight members of the research group to Room 218. When everyone arrived, he sat at the desk and scanned the crowd for a while, then knocked on the table and said, "The meeting begins. Come, Feifei Wu, you come first."
　　 Feifei Wu opened the PPT and showed the results of last week's experiments. The first is the J-V curve and photoelectric performance parameters of the two-dimensional perovskite device.
　　 "At present, the n-butylamine system has been optimized to 10%, which is very close to the 12.4% efficiency in the literature. The isobutylamine system developed by ourselves has the highest efficiency of more than 7%..."
"7%, 7%," Wei Xingsi repeated twice, and then stared at the projection screen for a long time. Then he said: "This efficiency value is ok. Wu Feifei and Sun Wo continue to optimize the device while you can start. Measure various characterization tests, such as the like. For the new field of 2D perovskite, the most important thing now is time. Our work must be fast and published in front of other groups, which is less efficient. No problem."
Wei Xingsi pointed to a stack of unbound documents on the desk next to him, and said: "Just put a fake, a few days later, I saw three more two-dimensional perovskite articles in the morning. Organize and bind."
"Okay~EbookFREE.me~ Feifei Wu responded and operated the laser pointer to continue the introduction: "This is a set of two-dimensional perovskite film pictures I took with my mobile phone. I placed them in the air. , Can keep the color unchanged for more than ten hours..."
　　As the effective layer of the perovskite photovoltaic material, it is tan under normal conditions and can achieve broad light absorption in the visible light range. However, if it is a three-dimensional perovskite material, it will quickly decompose and deteriorate after encountering water and oxygen in the air, and become 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. It is really obvious in comparison," Wei Xingsi nodded and added: "It's just a bit rough. It's best to keep the temperature and relative humidity the same every time you do stability experiments. Strict. I used a constant temperature and humidity box when I was abroad. Our group can buy one, and there is no need to pick too expensive one. It has basic functions."
Wu Feifei answered: "I have browsed the manufacturers of constant temperature and humidity cabinets before, and finally found a company that is located in Magic City. The cabinet has a small volume and a relatively narrow temperature range, but the price is more appropriate. More than 3,000 yuan."
　　Wei Xingsi didn’t hesitate much, so he made a decision directly:
This is ok, you can contact them directly to buy, remember to issue an invoice.

Later, Mr. 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 they are made organic. The air stability of non-fullerene materials not bad."