Chapter 214: The aggressive school girl and the self-released school girl

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The samples Xu Qiu had asked for from the photoelectric company in Shencheng had already been sent to Caiyi's concierge.
He hurriedly retrieved it. There were a total of seven polymer donor materials, each ranging from 10 mg to 20 mg, and they were packaged in small glass bottles. He did not deliberately avoid others and simply explained the way down.
The materials are blue, purple or black in fiber shape. Xu Qiu checked them and was very satisfied. They copied them to the simulation laboratory and transferred them to the spin-coated glove box for storage.
After reporting yesterday, he chose the course by the way on the course selection website. This semester there is only one "Graduation Design", which is equivalent to no class. Dr. Chen Wanqing's second year has completed all the courses. Han Jiaying has two courses, but not at all. on Monday.
So, after lunch, the organic trio took the school bus to Zhang Jiang laboratory.
Chen Wanqing completed the aldehyde grouping of the D unit last week and successfully purified it. This week, he plans to re-synthesize the A unit that failed last week.
Xu Qiu and Han Jiaying intend to continue the third step of the PDI system to synthesize dimer PDI.
There are two types of PDI dimers, one is the bridge type and the other is the torsion type.
For bridged synthesis, two molecules of monobromo PDI and one molecule of bis-trimethyltin substituted D unit react to form the structure of PDI-D-PDI. The D unit can be thiophene, dithiophene, vinyl, etc. The reaction principle of the yoke structure unit is Stille reaction, which is similar to the previous synthesis of polymer donor molecules, but because PDI is substituted by mono-bromo, the reaction will stay in the dimer and cannot continue to react to form the polymer.
The twisted synthesis is a new reaction. Two molecules of monobromo PDI, under the action of zinc powder and zero-valent palladium catalyst, undergo a coupling reaction to obtain the structure of PDI-PDI, usually using DMF as a solvent.
Although it is a new reaction, the difficulty of the two reactions is not great, and it is an entry-level experiment.
In the office, only Xu Qiu and Han Jiaying were preparing for the experiment. Chen Wanqing just repeated the experiment from last week, so no preparation work was required.
"Brother, how do we divide the labor?" Han Jiaying asked while sitting at the computer.
"Each person casts two reactions, one bridging type and one twisting type," Xu Qiu said casually: "Just follow the order of our previous synthesis. I will do No. 1 and No. 2, and you will do No. 3 and 4. , No. 1, 3 bridge type, No. 2 and 4 torsion type, each test 100 mg of water."
"No problem." Han Jiaying immediately started operating the laptop in her hand, calculating the amount of each reactant fed.
They had drawn the reaction steps in the CHEMDRAW software before, and directly framed the molecular structure of the raw materials, and the software could calculate its relative molecular mass.
Input the relative molecular masses of several raw materials and catalysts into the preset "Feeding Quality Calculation" EXCEL, and then input the feed equivalents of several reagents, and finally determine the initial mass of a certain raw material, you can automatically calculate each reagent Feeding amount.
A few minutes later, Han Jiaying picked up four sticky notes in her hand, handed two of them to Xu Qiu, and asked, "Brother, are there any precautions for the next experiment?" She has become a teacher to ask Xu Qiu before the experiment. got used to.
Xu Qiu thought for a while and said: "On the one hand, we must ensure anhydrous and oxygen-free conditions. The catalyst should be zero-valent palladium. You should understand. On the other hand, we must ensure the purity of the product and order it again before the reaction. Confirm with the board."
Han Jiaying nodded, and said with confidence: "It makes sense, Senior Sister Chen Wanqing was a lesson from the past last week. Seven or eight sample points are just like candied haws."
With the paper notes, the two entered the laboratory and stuck them on the glass of the fume hood.
Speaking of, the glass of the fume hood was marked by Duan Yun before Xu Qiu entered the research group. Later, at the unanimous request of Wu Feifei and Chen Wanqing, he wiped it clean with ethanol and acetone.
Now Duan Yun hardly comes to Zhang Jiang to do experiments. His materials, including N2200, PVDF and several metal nanowires, are all purchased through commercial channels, and then directly prepared in Handan's glove box, and then used He set up the test equipment for testing.
The perovskite quantum dot project that Tian Qingxin is responsible for may come to Zhangjiang for synthesis afterwards.
...
Start the experiment.
The solvent was re-evaporated. In the four reactions this time, DMF was selected. In fact, toluene was used as before. Theoretically, it was possible to use toluene. However, it was written in the literature as DMF and they were not replaced.
Prepare the reaction flask, add a magnetic stir bar, and prepare a nitrogen balloon.
Tap the board to confirm the purity of the medicine, weigh the medicine, add the solvent, connect the condensing device, the nitrogen ball, and draw three rows.
Add the catalyst, draw three rows in three, quickly heat up, and stick aluminum foil to protect the reaction flask.
Sure, the orange-red solution is like a pot of tomato soup.
The other reaction step was similar, and Xu Qiu quickly finished it again.
Then, he was surprised to find that Han Jiaying's reaction speed was not much slower than him, only less than a minute behind him.
It's not surprising to think about it, the senior sister is a robust type of experiment, so it is relatively slow, the senior sister is still relatively reckless in doing experiments, a bit like him.
Han Jiaying picked up the experimental garbage in the air and kicked, and asked casually: "Are we going back to Handan this week to make devices?"
Xu Qiu thought for a while and said, "After this product is purified, let's go back and make several batches of devices."
This is mainly to explain to the school girl and Teacher Wei. They don’t seem to have a simulation experiment system and can get efficiency data directly. Secondly, Chen Wanqing will use the liquid chromatograph in the next few days. If they go to Handan, it happens Can be used for peak shifting.
"Senior brother, how much efficiency do you think?"
"I guess 5%-6%. After all, it almost completely repeats the existing system. It can't be higher than the value in the literature." Before the simple PDI molecule can reach 3.5%, now the modified PDI dimer It is not difficult in theory to reach more than 5%, unless the synthesis reaction fails.
"Unfortunately, this result cannot be used to post articles."
"That can't be helped. The dimer has been studied for many years, and the molecular structure is limited. Basically all conceivable structures have been published," Xu Qiu said, "However, the operating space of 3D-PDI is much larger. Now, the middle nucleus can be adjusted at will, there are many possibilities."
"In fact, I have been thinking about 3D-PDI during this period and have some experimental ideas."
"Oh, let's talk about it." Xu Qiu's eyes lit up, and she suddenly became interested.
"In common organic photovoltaic materials, thiophene rings, which are also aromatic rings, are obviously more used than benzene rings. However, in the first 3D-PDI work, they used triphenylamine and did not introduce thiophene." Han Jiaying paused. Continue:
"I think it might be possible to make improvements based on their system, such as connecting three or even four thiophenes to the benzene ring, and then connecting them with PDI molecules to form a 3D-PDI structure."
"Brother, what do you think?" After speaking, Han Jiaying stared at Xu Qiu expectantly.
"This idea is good, it has a certain feasibility." Xu Qiu naturally praised it. The school girl was very happy after hearing it, her eyes narrowed into a small crescent.
Most of the time before, he put forward the experimental idea and let the school girl execute it, but now she has developed her own experimental idea, and the analysis still makes sense.
This made him feel that his son was finally raised.
In fact, Xu Qiu was not idle during this time, he took the time to list several feasible molecular structures.
Then, with the DFT simulation in the simulation laboratory, some unreasonable steric hindrance structures were eliminated, and more than ten feasible solutions were obtained, and this idea of ​​the school girl is one of his options.
...
After that, Xu Qiu and Han Jiaying purified four products.
Because the raw materials are very pure, and there are almost no side reactions in this step, there is only one main product obtained, and the purification difficulty is not high.
The yield is roughly between 50-70%, and only a few tens of milligrams of product, but it is temporarily enough.
The characterization data sent by the school girl last week returned one after another, and the results were almost the same as those obtained by Xu Qiu in Simulation Lab II. After receiving the news, Han Jiaying and Chen Wanqing were both happy.
Xuemei was very happy because the result of the characterization verified that her previous conjecture was correct, and the reactions of her and Xu Qiutou afterwards were all based on her "inference".
The senior sister has verified that the D unit is substituted by a dialdehyde group, and can carry out the post-reaction with peace of mind.
In addition, Xu Qiu also obtained the first batch of device data based on synthesized PDI molecules ~ EbookFREE.me ~ the highest efficiency value is 5.21%, the system is PCE10: PBI-5, and the devices are of course made by Han Jiaying.
PBI is the name of the PDI dimer, followed by the number representing the number of carbon atoms in its side chain, or the name of the bridge unit, such as PBI-5, PBI-2-T and the like.
Xu Qiu used the simulation laboratory II, consumed 12 hours, 1200 points, based on the four PDI dimer receptors, and initially traversed the existing donor library, the highest efficiency value was 5.86%.
Then, two preliminary experimental conclusions were obtained:
First, the photoelectric performance of the bridged PDI dimer is worse than that of the torsion type. Of course, this is only a preliminary conclusion, because there are many variables, which may also be related to the selection of the intermediate bridge unit.
Second, after the dimerization of the PDI molecule, the number of side chain carbon atoms is required to be more than that of the simple PDI molecule. Xu Qiu speculated that because the size of a single molecule has become larger, more side chains are needed to ensure the original solubility. .
In general, the foundation of the PDI system has been laid.
The nominal leader of the organic trio, Chen Wanqing has been staying in Zhang Jiang's laboratory, and even ran over on Saturday for an extra day.
After two weeks, she finally paid off and got the first batch of small A-D-A molecules she synthesized, and she named it C1.
Although Xu Qiu and Han Jiaying both complained about the name, the senior sister didn't mean to change it. It seemed that she was planning to release herself.
Then, Xu Qiu secretly used Simulation Lab II to help her experiment on Sunday-based on the current donor library, it took 5 hours and the highest efficiency obtained by the initial traversal was only 0.67%.
emmm...
I don't know what the senior sister will feel when she gets this result.