I Have a Research Support System

After exiting the simulation laboratory II, Xu Qiu came to the vacuum oven and turned off the heating device and vacuum pump.

Then, rotate the air release hole on the side of the instrument, and carefully put air into the chamber of the vacuum oven. If the air release rate is too high, the solid powdery medicine wrapped inside the filter paper may be blown away, causing the experiment to directly GG.

The barometer reading on the vacuum oven rises slowly, and returns to normal atmospheric pressure after about half a minute.

Xu Qiu turned the handle, opened the hatch of the oven, took out the filter paper bag, and unfolded it carefully.

The filter paper was baked warmly, and the dark red powder on it was completely dry at this time, and there were no traces of solvent.

After all, the set temperature is 70 degrees Celsius, which has exceeded the boiling point of methanol solvent at about 65 degrees Celsius. Therefore, although the drying time is only more than one hour, the task has been successfully completed.

In fact, if you are not in a hurry to submit a reaction, the best treatment method is to vacuum dry the drug at 40 or 50 degrees Celsius at a relatively low temperature, and then last for a longer time, such as 6 hours or even overnight.

The main consideration is that under high temperature conditions, drug molecules may be decomposed. For example, drugs such as organotin reagents may be detinned. However, the chemical stability of PDI molecules is very good, so there is no need to worry too much.

Xu Qiu used a stainless steel spatula to transfer the trinitrated second-generation 3D-PDI molecules on the filter paper to weighing paper, and weighed the mass.

41.2 mg.

The quality of the raw materials is higher than that of the original feeding.

This is also normal. The nitration reaction is to replace the position of a hydrogen atom with a nitro group, and introduce three nitro groups into the molecule, which can increase the relative molecular mass of about 135.

Calculated, the yield is 99.6%, rounded up, 100%!

Xu Qiu put away the product and began to prepare for the next step of the reaction—the reaction of selenium powder with the trinitrolated second-generation 3D-PDI molecule at high temperature.

In this reaction, the selenium atom will replace the position of the nitro group, and at the same time connect with another carbon atom on the current PDI molecule, forming a single bond again.

Generally speaking, (1, 2), (3, 4), (5, 6), six active sites, for the nitration reaction in the previous step, each only takes one site.

As for the selenium atom, I'm sorry, I want all of them. Each selenium atom occupies two active sites at the bay position, forming a five-membered ring structure.

This is why the reaction in the previous step does not need to distinguish the three products.

Because even if it is a mixed product, after this step of introducing selenium atoms into the reaction, it will eventually return to a unified final product.

Xu Qiu went to the reagent cabinet, took out the reagent bottle containing selenium powder and the N-methylpyrrolidone solvent bottle, and transferred them to the fume hood.

Selenium powder is an inorganic non-metallic material. There are not many organic solvents that can dissolve it. It is soluble in concentrated sulfuric acid and chloroform, slightly soluble in carbon disulfide, and insoluble in water and ethanol.

Obviously, concentrated sulfuric acid is not a good choice as a solvent. Chloroform, that is, chloroform, has a too low boiling point, only about 60 degrees Celsius, and is also not suitable for this reaction.

Therefore, the solvent chosen this time is N-methylpyrrolidone, referred to as NMP, which is a strong polar solvent. It can not only dissolve selenium powder, but also has a boiling point as high as 200 degrees Celsius, which is very suitable for this reaction.

NMP is a colorless transparent oily liquid with a certain viscosity, which is different from commonly used toluene, dichloromethane and the like.

It is said that this thing has the smell of amine, but Xu Qiu did not go up to sniff it desperately.

He directly used a disposable dropper to draw about 10 ml of solvent into the two-necked flask. This time, he did not need to distill the solvent again, which was more troublesome.

After finishing the reaction solvent, Xu Qiu picked up the reagent bottle of selenium powder and looked it over.

It is marked with "Se powder, high-purity selenium powder, 99.99%", as well as the CAS number of the drug, 7782-49-2, and information about the manufacturer.

The CAS number of a drug is very similar to the ID number of a resident. Each CAS number usually corresponds to only one drug, but the same drug may correspond to multiple CAS numbers.

Xu Qiu has checked the information before, and the selenium powder is poisonous, and it is in powder form, and it is easy to diffuse into the air during the weighing process.

Therefore, he took the reagent bottle of selenium powder to the fume hood specially for inorganic synthesis reactions, and weighed it with the balance here.

Open the fume hood, pull the glass of the fume hood to the bottom, unscrew the cap of the reagent bottle of selenium powder, scoop up a small spoonful of black-gray powdered selenium powder with a medicine spoon, transfer it to the weighing paper on the peeled balance tray, and put it together Glass door on the side of the scale.

The selenium powder in this reaction is in large excess, so the weighing need not be particularly precise.

In the end, Xu Qiu weighed 40.1 mg of selenium powder and quickly transferred it to a two-necked flask, which was about 30 equivalents to the nitrolated 3D-PDI molecule.

He grabbed a clean shuttle-shaped magnetic stirrer, threw it into the reaction bottle, clamped the reaction bottle on the iron clip, immersed it in the oil bath, started heating and stirring, set the temperature to 70 degrees Celsius, and the speed to 400 r.p.m.

While waiting for the selenium powder to dissolve, Xu Qiu began to prepare. This reaction requires nitrogen protection and does not require condensation and reflux. Just use a three-way valve to set up a nitrogen balloon.

Then, install a nitrogen balloon, three pumps and three rows, add nitro-ated 3D-PDI raw materials, three pumps and three rows, quickly heat up to 190 degrees Celsius, increase the speed to 700r.p.m., and wrap the reaction bottle with aluminum foil.

"It's finally finished." Xu Qiu muttered to himself, and looked at the stopwatch hanging beside the fume hood, "It's past eleven, and it's almost twelve, let's send a message to my junior."

Take off the sweaty gloves, take off the lab coat, and return to A501.

Picking up the phone to look, I received a row of messages from schoolgirls.

"Brother, I'm in the dormitory."

"I'm done taking a shower."

“[Where are people]”

"I'm so sleepy."

"I really want to sleep."

"[voice]"

"[voice]"

Xu Qiu clicked on the two voices, and the soft voice of the school girl came from the receiver, "Huh~ I almost fell asleep just now." "Wait for me, I'll go wash my face."

"It's nice to have someone miss you," Xu Qiu smiled, and was about to reply when he received another message.

"Great summoning technique, show up, brother."

"[I am coming]"

"Hey, the summoning was really successful."

"I have been experimenting before, I didn't bring my mobile phone, and I just finished my work."

"Brother, thank you for your hard work. The experiment is going well."

"not bad."

The two chatted for a while and said good night to each other.

As we all know, staying up late starts after good night.

Xu Qiu put down his phone and returned to the laboratory.

Just now he was eager to report to his junior that the laboratory was not closed yet.

After checking several fume hoods, several reaction bottles were normal, so Xu Qiu turned off the water, electricity and gas in the laboratory with peace of mind, locked the door and left.

Go back to A501, brush your teeth and wash your face, but unfortunately the conditions here do not allow you to take a shower.

Although the bathroom in the Handan dormitory only has cold water supply, at least there is a shower head. If you use a thermos to get two pots of boiling water downstairs, with the shower head, you can even take a hot bath.

The school girl also goes back late every day, that's how she takes a bath, as for how Xu Qiu knew, anyway, he didn't take the initiative to ask.

And Zhang Jiang's bathroom doesn't even have a shower head.

It is normal, after all, it is a laboratory building, not a dormitory.

Therefore, there is a sprinkler and eyewash in the corridor on the fifth floor, next to the gate of A502, but this is for emergency use in case of accidents, and cannot be used for private use.

For example, if a chemical agent is accidentally splashed into the eyes, you can use an eyewash station to provide a large amount of water to rinse the eyeballs, or if your clothes are on fire, you can use a shower to cool your heart.

Putting aside the messy thoughts in his mind, Xu Qiu looked at the time, it was past twelve o'clock in the morning.

He resolutely lay down on the bed, closed his eyes and counted the sheep for a while, then fell into a deep sleep.

...

The sun is shining and a new day has arrived.

Xu Qiu got up at eight o'clock, washed up briefly, and went to the cafeteria for breakfast.

On the way, he entered the simulation laboratory II to check the results. The preliminary exploration of the photoelectric properties of the three first-generation 3D-PDI molecules, namely the PDI3-B-5/6/8 series, has been completed.

Because of the previous exploration experience (the first generation 5/6 series, the 6 series is higher, the highest value is 4.37%), this time the simulation experimenters control the parameters more carefully, and the final photoelectric efficiency of the device is higher than Once improved.

Of course, it may also be because the product of this reaction is better.

In any case, the final result is that the efficiency of the first-generation 5 series is still at the bottom, with a maximum efficiency of 4.22%. The photoelectric performance of the 6 series and 8 series is comparable, with the highest values ​​of 4.55% and 4.60% respectively.

Based on the existing donor library, the best suitable donor materials are all P3TEA, and the second best suitable donor materials are all PCE10.

After getting this result, Xu Qiu began to analyze.

Last week, the second-generation 3D-PDI is the 5 series of molecules obtained through photocyclization, with a maximum efficiency of 5.41%. If it is replaced with the 6/8 series, the probability can be increased again, perhaps reaching 6%.

It's a pity that in the first generation of 3D-PDI, the efficiency of the 8 series is not significantly improved compared to the 6 series, only 0.05%. Whether the series can widen the gap.

At present, the third-generation 5 series 3D-PDI is still undergoing selenization reaction in the laboratory. This material is very critical. If it is improved compared with the second-generation 5 series, there is a high probability that this strategy can be simultaneously applied to 6 /8 series.

Well, today's task is also determined, vote for three reactions, synthesize the second-generation 5/6/8 series molecules in large quantities, and do a good job in the post-reaction processing of the third-generation 5 series molecules.

Returning to the microelectronics building, Xu Qiu went to the laboratory alone and opened the windows to ventilate before the seniors and juniors came.

The estimated reaction time of the selenization reaction is 12 hours, and the high temperature is 190 degrees Celsius. The reaction conditions are quite intense, but because of the nitrogen protection, the chemical stability of the PDI molecule is good, and there are no possible side reactions, there is nothing to worry about.

Xu Qiu originally wanted to order a board to have a look, but with the high temperature reaction and nitrogen protection, the solution in the reaction bottle must be lowered to room temperature, and then it must be pumped three times to remove oxygen and heat up again, which is too troublesome. I had no choice but to give up.

'Anyway, I'm not in a hurry for this moment, so I'll wait for another three or four hours. It's just during this time that I can vote for those three reactions. '

Thinking of this, Xu Qiu began to prepare for the experiment. There is only one raw material for the photocyclization reaction, which is the first-generation 3D-PDI molecule, and iodine is used as a catalyst.

In fact, it is not very strict to say that iodine is a catalyst, because the composition, chemical properties and quality of the catalyst itself do not change before and after the reaction. In fact, iodine is consumed during the reaction. When two carbon atoms form a ring, When directly connected by a carbon-carbon single bond, two hydrogen atoms will be removed, which just combine with iodine to form hydrogen iodide.

Xu Qiu first set up the device for re-steaming toluene, and then tested the purity of the three reaction raw materials by spotting the plate.

Everything was ready, he took three clean reaction bottles, and added three kinds of first-generation 3D-PDI molecules that had been weighed. For this reaction, he directly used all the stock that was separated and purified yesterday. About 300-400 mg.

Subsequently, 100 ml of redistilled toluene was added to dissolve the raw materials, 1 mg of iodine was added, and a 500-watt high-pressure mercury lamp was set up to start the reaction.

Xu Qiu was very careful during the whole process, because this time it was a large-scale response, and no mistakes were allowed.

...

At about half past nine, Chen Wanqing and Han Jiaying appeared at the gate of A501 together.

The three chatted and laughed for a while, Xu Qiu stayed in the office, and the other two went to the laboratory.

Thinking about the cover of yesterday's article, Xu Qiu sent Tian Qing a WeChat message: "Sister Tian Qing, how is the cover?"

Quick response, "I've got a first draft, what do you think?" "[image]"

Xu Qiu clicked on the picture, and it was obviously hand-painted by Tian Qing. The overall style was the same cartoon style as before, but now there is no complete coloring, and some parts are simply outlined.

The content is very rich, and it can be seen that she has put in a lot of effort, and her understanding of organic photovoltaics is not low.

On the upper left is a golden sun, constantly radiating sunlight, as the beginning of energy;

On the upper right is a cartoon PCE11 molecule and a PC[70]BM molecule, smiling and holding hands, as if to say "we all have a bright future", which is the core highlight of Xu Qiu's article.

The lower left is an anatomical diagram of the layers of the organic solar cell device, including glass substrate/ITO/transport layer 1/effective layer/transport layer 2/metal electrode; the lower right is the enlarged view of the effective layer, or the microscopic appearance .

In these two parts, Tian Qing shows the whole process of converting solar energy into electricity:

Material absorbs light energy, excitons (electron/hole pairs) are generated, excitons are split into free electrons/holes, free electrons/holes are transported inside the acceptor/donor respectively, electrons/holes are transported by the electrode collected to form a photocurrent.

On the whole, Xu Qiu was quite satisfied, so he replied: "The painting is not bad, I showed it to Teacher Wei."

"I've read it, and he said it's okay, do you have any comments, junior?" Tian Qing replied.

"The core of PC[70] BM is C-70, which is ellipsoidal. It is drawn as a sphere in the picture. It can be changed." Xu Qiu thought for a while and asked a small question.

"Okay, I'll change it up. I'll be lustful today, and I'll post-process it with PS to finalize the draft."

"Sister Tian Qing has worked hard, I will treat you to dinner when I get back."

PS: I asked for a monthly pass at the beginning of the month. I updated almost 200,000 words last month. I will continue to work hard this month and strive for more outbreaks!