Chapter 249: History is always surprisingly similar

Early on Saturday morning, Xu Qiu entered the simulation laboratory full of expectations, and soon received the results of a new wave of exploration.
　　 His third-generation 8 series 3D-PDI molecules have optimized the highest efficiency to 8.43%, the donor material used is P3TEA, the device processing solvent is a chloroform/dichlorobenzene mixed solvent, and the addition amount of dichlorobenzene is 4.5%.
　　8.43%!
　　 This is a complete break of the original world record, 7.92%, and it is a small step forward.
　　 On the other hand, Han Jiaying's second-generation B4T system has a maximum efficiency of 7.33%, and the donor material used is PCE10. The mixed solvent of chloroform/dichlorobenzene is also suitable for processing solvents, and the addition amount of dichlorobenzene is 8%.
The efficiency improvement of the 　　 school girl system is relatively small, and with the current step, there is not much room for further optimization, and there is a high probability that it will not exceed 8%.
However, her system is currently only the second generation. If selenium atoms are introduced from the original PDI molecule to synthesize a third-generation product similar to Xu Qiu, the efficiency will exceed 8%, or even higher, there is still a big possibility. of.
Thinking of this, Xu Qiu couldn't help muttering to himself that he wouldn't be bursting with chrysanthemums by a school girl just a few days after breaking the record. After all, the efficiency of his second-generation 8 series is only about 6%. This is 7.3%. If we iterate again, don't we have to go to heaven.
　　 Then I thought about it, if she was really blown up, then blow her back again.
　　 After summarizing the results of his experiment with the school girl, Xu Qiu looked at the school girl's system.
　　 Her two acceptor materials have traversed more than a dozen commonly used donor materials in the simulation laboratory.
　　 Although the senior sister named them, Xu Qiu still gave them a more general name based on their molecular structure. He felt that such naming was sometimes more intuitive.
　　 Among them, CH1, with F8 in the center as the D unit, and two 1,3-indenedione (IN) connected to the side as the A unit, so it is named F8-IN;
　　 Similarly, CH2 is named IDT-IN.
　　 First of all, based on the F8-IN system, Xu Qiu took a look at the efficiency.
　　 Hundreds of devices, hundreds of conditions, at first glance, all start with zero eggs.
　　 up to 0.3%...
　　 How can it be a tragic capital letter?
　　 In fact, when Xu Qiu saw the F8 unit, he was not surprised that the maximum efficiency of the F8-IN system was only 0.3%.
　　 The F8 unit is a very old structural unit, which can be traced back more than ten years, perhaps even longer.
Among them, "F" represents the fluorene unit, and the alias of fluorene is dibenzopentacyclic. As the name implies, it is a five-membered ring sandwiched between two benzene rings, and there is a sp3 hybrid carbon atom in the middle of the five-membered ring. "8" represents this Two straight-chain alkyl groups of 8 carbon atoms are attached to the side chain of the sp3 hybridized carbon atom.
　　 fluorene is one of the separation products of coal tar. It is backed by petrochemical chemical raw materials, which are sold by ton, so it is very cheap.
　　 And when a field develops in the early stage, it is natural that something is cheap, and something is readily available, so let’s try it first. Moreover, fluorene-based materials have made great achievements in the field of photoluminescence.
　　 As far as Xu Qiu knows, when Mr. Wei was in the beautiful country, he studied F8-based polymer donor materials, including 2, PF8DTBT and the like.
　　 However, this type of material has hardly spread to the present.
　　 Nothing else, the device efficiency is too low, all of them are on the street.
　　 The Internet has memories, and research circles have memories as well.
　　 Ten years later, a failed system, unless you deliberately read the earlier related literature, basically you will no longer find it.
As for why Chen Wanqing re-selected the F8 system and used it in organic photovoltaic materials, it may be influenced by Teacher Wei. After all, his scientific research experience before returning to China must be part of the inheritance, and he wants his students to complete it. For example, the PDI series now handed over to Xu Qiu and Han Jiaying.
　　 Or maybe the senpai just showed her...her traditional performance again.
　　 After many years, the F8 system has re-emerged, but once again hit the street.
　　History is always surprisingly similar.
　　Xu Qiu was a little surprised by the efficiency of another CH2 system.
　　 The highest efficiency is 2.87%!
　　 was actually close to 3% in the first test. You must know that the current maximum efficiency of the A-D-A system is only 6%.
　　 If this is to be optimized again, the efficiency is above 3%, and the A unit is a newly developed structure, it is not bad innovation.
　　Comprehensively, it is enough to send an article like CM on the junction of one and two districts, and even work hard to make an impact;
　　 If the efficiency can be higher, 4% or 5%, then there will be a chance. The first 3D-PDI system article reviewed by Xu Qiu some time ago was also 4% efficient, so it was sent to JACS.
　　 "Senior Sister finally came out of the 1% quagmire. This is going to work hard. Her one-section article dream is likely to come true."
　　 "Could it be that the previous failures allowed her to accumulate a lot of character, but this time she suddenly broke out?"
　　 "The design of this molecular structure seems to have part of my influence."
　　 "Anyway, this is always a good thing."
　　 Xu Qiu pondered for a while and began to study the CH2 data carefully.
In the IDT-IN system, the D unit used is the IDT structure. IDT is a structure that has recently emerged in the field of organic photovoltaics. The molecular structure is relatively complex. It is composed of four thiophene rings and one benzene ring connected by linear fused rings. There are four The side chain site, the Chinese-English translation name is Yinda Province and dithiophenes.
　　 Interestingly, in the most efficient system, the donor material used is not a common narrow band gap material, such as A, but a rare wide band gap polymer donor FTAZ.
　　 After thinking for a while, Xu Qiu probably understood the reason, which should involve the issue of complementary light absorption.
For traditional fullerene derivatives and non-fullerene PDI acceptors, the light absorption range is usually 300-600 nm, which is a wide band gap material. Therefore, the matching donor material should be selected in the light absorption range Narrow band gap material near 500-800 nm.
　　 Unlike the A-D-A molecules synthesized by my sister now, the light absorption range can be controlled by adjusting the structure of D and A units.
　　 For example, the color of CH2 is blue-black, and it is a narrow band gap material. Therefore, it is better to match the donor material with a wide band gap to ensure complementary light absorption.
　　 It is worth noting that although they are all narrow band gap materials, their light absorption ranges overlap greatly, but based on the system, the highest efficiency can reach 2.46%.
　　In this way, PCE10 can become the standard donor material in the field of organic photovoltaics in recent years. There are indeed two brushes
　　 The universality of this material is indeed good enough, and it can be adapted to most newly developed receptor materials, even if the light absorption is not complementary.
　　 After all, other people are not like Xu Qiu, they can try different conditions in large quantities through the simulation experiment system.
　　 For Xu Qiu, as long as he has no problem grasping the general direction, one day in Simulation Lab II can complete the workload of others for one month.
　　 I have to say that the system is still very powerful in this respect.
　　 For most researchers, the general approach is to choose a system with a not too bad foundation, and then go one way to the end, and keep trial and error.
　　 They are also very helpless. They can't do a system for half a month or a month, and then suddenly change to a new system. The sunk cost is too high.
　　 Therefore, a material with universal applicability like PCE10 is naturally sweet, even if the highest value cannot be obtained, it is not bad to get a higher value.
　　 Of course, in the long run, if various types of narrow band gap A-D-A acceptors are widely studied in the future, it is bound to synthesize the corresponding wide band gap donor materials, which are similar to materials like FTAZ.
　　……
　　On Sunday, Caiyi 216, the research team should have 7 people, but there are actually 6 people.
　　With Han Jiaying's help, Xu Qiu doesn't need to make the parts himself.
Although 8.4% of the results have been obtained in the simulation laboratory, considering the direct replacement of the solvent, the change of the thickness of the molybdenum trioxide, and the preparation conditions of the zinc oxide transmission layer are relatively abrupt, Xu Qiu did not adopt the new conditions for the time being, but let the school girl The previous experimental conditions have been slightly modified, allowing free play.
　　 He intends to keep the system between him and his schoolgirls in the next week when he personally conducts the experiment.
　　 Today's main task is to make the senior sister's CH2 system stand out.
　　 Xu Qiu suggested that she use the system. Although I know that FTAZ is more compatible, it is impossible to use FTAZ directly in exploratory experiments.
　　 After arranging the work of the school girl, Xu Qiu began to write articles.
　　 Although I am writing a big article like NC, the pressure is not great.
　　 On the one hand, an article like him whose highlight is "breaking records" is much easier to write than an article with "new structure" and "new viewpoint" as its highlight.
It’s very simple. You put the efficiency data on the title of the "breakthrough record" type of article. After seeing the data, your peers will know that you are NB at a glance. There is no need to say anything in the body, as long as the story is told normally. Yes, others will naturally supplement your brain according to your molecular structure and synthetic route.
But if a "new structure" or "new viewpoint" is proposed, a lot of words must be used to express it, such as: where is this "new" new and where it is powerful; why is this "new structure" and "new viewpoint" proposed? and many more.
　　 On the other hand, Xu Qiu is no longer a scientific researcher at the time. I still remember when I wrote an article for the first time, he wrote it for more than a month, and finally changed it many times.
Up to now, Xu Qiu has accumulated a lot of various routines and words in the field of organic photovoltaics. It seems that as long as the characterization data is complete and the article is clear, he will be given a week to complete an article ~EbookFREE.me~ It seems It is not too difficult.
　　 After all, the text is only three to five thousand words. As long as the mind is coherent, there is no problem writing 10 words in a minute, and that is 600 in an hour. Even if it is slower, writing 5 words in a minute, there are 300 words in an hour.
　　In terms of time allocation, two days for the main text, two days for processing data, graphics, and references, one day for fine-tuning, and two days for revising, almost like this.
　　 In the afternoon, Xu Qiu spent most of the time sitting at the desk with codewords, constantly filling in NC article templates.
Others in the laboratory, Chen Wanqing adopted Xu Qiu’s suggestion, first prepared a solution, and then stayed in the laboratory, put the mobile phone in disposable PE gloves, placed it on the platform next to the glove box, and moved it. A round stool was sitting next to the glove box, watching the drama while supervising Han Jiaying's experiments.
　　 Sun Wo saw the posture of Chen Wanqing and Han Jiaying and decisively gave up the idea of ​​making devices today and stayed in the office to sort out documents.
　　 Duan Yun was doing thermoelectric experiments while scanning the web page. Each test lasted a long time, and it took up two KEITHLEY source meters at the same time, but he did not need to be there to stare most of the time.
　　Wu Feifei wore headphones and focused on writing a review. Her work was the most special in the audience. Teacher Wei looked back at the progress of her essay to know if she had paddled. It is difficult to fish in quantifiable work.
　　 Tian Qing, people don’t know where they have gone, so they just didn’t show up. Everyone is not surprised at this. On weekdays, when Teacher Wei was there, she would occasionally be an hour late.