Chapter 188: 2 paths

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On January 28th, Xu Qiu's work of writing a summary plan came to an end.
He has integrated the third part of Chen Wanqing's responsibility into the plan, and now only the prospect part is left.
This year's Spring Festival is February 6, and the research team will be on holiday from January 31 to February 13.
Therefore, they have to submit this plan to Teacher Wei before the research team is off, and then Teacher Wei will be responsible for contacting the editor.
In the afternoon, Xu Qiu and Chen Wanqing sat at their desks and discussed the "Outlook" part of the review.
At the same time, they also called Han Jiaying to listen. The school girl mainly acted as an audience and recorded their discussions.
"I think before discussing the outlook part, we can discuss the direction we each plan to do next." Xu Qiu suggested.
"Yes, um..." Chen Wanqing thought for a moment, and said: "Those unsystematic molecular structures, that is, other categories in the review can be excluded first, then choose from the three mainstream directions, brother, you Any thoughts?"
"I think the N2200 series can be eliminated first of the remaining three systems." Xu Qiu said without hesitation: "In the field of organic photovoltaics, long-term research experience has shown that there are two materials for giving and accepting, and one is for polymer. Another choice is small molecules, so the combination of photoelectric performance is better.
The theoretical basis is that from the perspective of morphology, the combination of such small polymer molecules makes it easier to form a bicontinuous interpenetrating network structure, that is, a three-phase structure.
At this stage, I think we must not deviate too much from other researchers in choosing the general direction. "
"Well, I agree, the performance potential of all-polymer or all-small molecule devices is indeed limited," Chen Wanqing asked again: "Then there are only two options left, PDI series and ADA series, which one do you prefer? ?"
"Both paths have their advantages and disadvantages," Xu Qiu paused and said, "To be honest, I haven't thought about it yet."
"In fact, I am more optimistic about the A-D-A series." Chen Wanqing said.
"Oh? Why?" This time it was Xu Qiu's turn to be surprised. These two routes are biased in his heart, but they are at most four or six. He is still entangled, but the senior sister has directly identified them. A route.
"A woman's intuition." Chen Wanqing smiled, and Han Jiaying, who was watching beside her, couldn't help but chuckle.
"Okay," Xu Qiu raised his head, looked at the senior sister, then looked at the senior sister, and tentatively asked: "The senior sister, do you have any specific research ideas?"
"No." Chen Wanqing shook her head.
"Okay." Xu Qiu raised his forehead again, and sure enough, the senior sister was really as usual...
"However," Chen Wanqing said, "I think about the outlook part. Let's talk about the specific experimental ideas. Anyway, there is a winter vacation transition, so it's not in a hurry."
"Sister, it’s good if you know what is going on," Xu Qiu did not forget what was going on. He pulled the topic back to the overview and began to analyze: "The two paths have their own advantages and disadvantages. Let me talk about my thinking.
PDI derivatives are optimized around the initial perylene diimide molecules. The electron mobility of this type of material is higher, which is comparable to that of traditional fullerene materials.
And there is a perfectly matched polymer donor material PTB7-TH. The main problem to be solved is the destruction of the morphology of the blend film by the high crystallinity of PDI.
The advantage is that the path is simple, just focus on the crystalline properties of the material, and other researchers have done a lot of preliminary work. The current basic value of efficiency is relatively high, up to 8%.
At the same time, the shortcomings are also obvious. There is only one molecular structure of PDI, which is relatively simple, the light absorption range is relatively fixed, and the upper limit of the material's performance may be relatively low. "
"Brother, slow down." Han Jiaying interrupted suddenly: "I can't remember."
Xu Qiu nodded and expressed his understanding. This is indeed new knowledge for the school girl. She is not like him and the school sister. They have recently made up some non-fullerene-related literature.
So, he repeated it again, slowed down, and helped the school girl to record the main points, and then continued to analyze:
"The small molecules of the ADA series are small molecule receptors connected by three units A, D, and A. The two A units are the same, and the D unit is usually also axisymmetric. Therefore, the molecule is usually an axis. Symmetrical structure.
The advantage is that the molecular structure is more flexible, and the physical and chemical properties of the D unit and A unit can be adjusted by adjusting the structure of the D unit and A unit, such as the light absorption range, energy level structure, and even the morphology of the blended film. The upper limit of the performance of the material may be relatively high.
Disadvantages, the current efficiency is very low, only about 6%, it is not clear whether it can be higher in the future.
And I don’t know the reason for the inefficiency. There are many related claims, and it is not clear which is correct. One claim is due to the relatively low electron mobility of the material.
There are not many people doing this series of research, mainly in a few groups in China. Mr. Wei’s friend Gong Yuanjiang is one of the main players. "
"Well, what's your tendency for the younger brother?" Chen Wanqing asked, Xu Qiu's overall is in place, basically in line with her ideas, and it is not too difficult to get these conclusions. Just read the dozens of related documents thoroughly. .
"PDI derivatives and ADA molecules, my personal tendency is to open June Fourth, but since the senior sister chooses the ADA series, then I will choose PDI derivatives." Xu Qiu said, he was influenced by Mr. Wei, and his influence on the PDI system A lot of extra attention has been paid, and preliminary experimental ideas have been generated in my heart.
"Why, don't you want to be in the same field as me." Chen Wanqing suddenly changed a bitter tone and said: "Han Jiaying must be with you, hey, I have to fight alone again."
"Since ancient times, confidantes are so fate~~~" Chen Wanqing said griefly.
"Senior sister, don't be like this." Xu Qiu raised her head again, asking if she had watched too many TV series recently, she had replaced herself again.
However, he explained patiently: "I am out of insurance considerations. If we all study the same field, if we fail, we have to start from scratch. But if we divide into two fields, suppose one of them With a major breakthrough, if there is no prospect in another field, you can temporarily give up and focus on the field where the breakthrough is made.
As long as we maintain communication, it is not very difficult for us to switch research fields at this level. "
"Okay, it sounds reasonable. I can barely persuade me." Chen Wanqing returned to normal, and then moved and said: "Han Jiaying, which field do you want to do more, is it a PDI derivative?"
"Yeah, yes." Han Jiaying's cheeks were slightly red, and she responded in a low voice.
"You two," Chen Wanqing looked at them back and forth, and said; "Forget it, let's not talk about this, let's continue to discuss the summary."
"Well," Xu Qiu's face was not red and heartbeat, and calmly said: "Then we will focus on the two directions of PDI derivatives and A-D-A series, and give some ideas. Other areas can be downplayed, and there is no harm in writing less."
Speaking of business affairs, Chen Wanqing returned to a serious state: "I mainly supplement the ADA series. I have accumulated a few ideas during this period. First of all, the D unit used in the binary DA copolymer donor material can be introduced into In ADA molecules, such as IDT and IDTT, they happen to have large conjugated fused ring structures, which are also matched with ADA molecules."
"Will it be too difficult to synthesize this way?" Xu Qiu frowned, but he stretched out quickly and said to himself: "The difficulty of synthesis is not something we need to consider, as long as it is reasonable."
"Yes, it's a prospect after all," Chen Wanqing smiled and said: "There is also the low electron mobility and poor charge transport of ADA molecules. I have an idea to improve the electron withdrawing ability of the terminal A unit. It can increase the dipole in the molecule, and perhaps solve this problem to a certain extent."
"This is fine." Xu Qiu nodded. The two points raised by the senior sister are almost enough for the prospect of the A-D-A series.
He began to talk about his thoughts: "The main idea for the optimization of PDI derivatives is to reduce their crystallization performance. A common method currently available is to dimerize PDI.
I think it is possible to further gather and gather together. Of course, I also face the problem of high synthesis difficulty, but from the perspective of thinking, it should be no problem.
Another idea is to change the single carbon-carbon single bond between the dimers to multiple carbon-carbon single bonds, which can compensate for the decrease in crystallinity caused by the dimerization to a certain extent, so that the crystallinity is between The intermediate state between the individual molecule and the dimer ~EbookFREE.me~ makes the material performance optimization smoother.
Moreover, this method can be further extended to trimers and tetramers. "
"Yes, I have a lot of ideas, I think we can try to do it ourselves." Chen Wanqing applauded.
"Actually, I still have an idea, but the space in the summary plan is too small to write." Xu Qiu smiled.
"Speaking of people." Chen Wanqing said in an unpleasant way.
"I want to keep this idea for myself, and don't want to write it in the review." Xu Qiu said.
"Then keep it, just count you." Chen Wan gave him a clean look and continued: "The four or five points we just said, plus some conventional ones, such as non-halogen solvents, air stability related The research is almost done, do you have anything to add?"
"Let me add one more point," Xu Qiu said: "The N2200 system is also a DA copolymer, but an acceptor polymer. The A unit is NDI and the D unit is two thiophenes. The structure of NDI is similar to that of PDI. I feel that PDI molecules can be substituted for NDI molecules."
"That's good, I think maybe I can publish an article," Chen Wanqing's eyes lit up and asked: "Are you willing to write it in the review? Don't you stay and do it yourself?"
"I came up with this casually. If the senior sister likes it, I will keep it for you." Xu Qiu smiled.
"That's not necessary," Chen Wanqing waved her hand: "I will still focus on the A-D-A series in the future."
In this way, the two again embarked on two different paths.
Last time, Xu Qiu chose the P4T system and finally got PCE11 materials, and received an AM and several other articles.
This time, he doesn't know what the future will be like.
It is enough to do everything, obey the destiny, be yourself, and have a clear heart.