Chapter 262: Sister in self-doubt

The other friends in the research group all know that Xu Qiu and Chen Wanqing were called away by Teacher Wei early in the morning.
Now seeing them holding a new document of "Nature·Materials" in their hands, various speculations have emerged in their hearts.
Han Jiaying sat next to Xu Qiu and asked softly, "Brother, what's the situation?"
Xu Qiu briefly introduced a few sentences: "Xu Zhenghong's research group just published an article "Nature·Materials", and they broke the efficiency of the ADA system to more than 10%..."
His voice is not too big or too small, just enough to be heard by everyone around him.
Han Jiaying is in the organic field. After listening to the beginning, she understood in an instant, analyzed the stakes in it, and then offered a comforting look at the senior sister.
Although Wu Feifei, Duan Yun, and Tian Qing are not in the organic field, they have been fascinated by them in weekdays and group meetings. They quickly analyzed the publication of this "Nature·Materials" article, which is not good news for Chen Wanqing. , Comforted her one after another.
Only Sun Wo, who has just stepped into the scientific research circle for a short time, looked dumbfounded. Who am I? What are you talking about? Why are they all comforted all of a sudden?
After being comforted by everyone, Chen Wanqing was almost back to normal, and fell into self-doubt.
Wei Xingsi allowed everyone to discuss freely for more than a minute, until the voice slowly became smaller, then he tapped the table with his knuckles and said: "Let's start the meeting, Wu Feifei, you come first."
Feifei Wu wrote a review of "Research Progress in Perovskite Thin Films and Single Crystal Preparation Methods" last week, and completed the submission on Sunday. The target journal is Adv.Sci.
In addition to writing a review, she also took Sun Wo, supplemented Sun Wo tin-based perovskite material related characterization, including XRD, SEM, etc., and taught him data processing methods.
Today, she mainly talks about the literature review and the prospects for her future work:
"Next, I intend to change the research direction from a three-dimensional perovskite system to a Ruddlesden-Popper (RP) type perovskite material, or two-dimensional perovskite material."
"More than half a year ago, there were two documents, one JACS and one ACSNano (the grade is equivalent to AEM), and they first proposed the concept of two-dimensional perovskite..."
"In traditional three-dimensional perovskite materials such as MAPbI3, the introduction of amine organic structural units with bulky side chains, such as phenethylamine PEA, n-butylamine n-BA, etc., forms an organic spacer layer, thereby inhibiting the perovskite material Crystallization in three-dimensional directions yields two-dimensional perovskite materials with only a few or more than a dozen atomic layers in the crystal region...
"Compared with three-dimensional perovskite materials, the primary advantage of two-dimensional perovskite materials is that they have very good environmental stability and strong resistance to water and oxygen. The secondary advantage is that they have self-assembly characteristics and do not require reaction. Solvent, multi-step spin coating can get a smooth film, etc..."
"However, compared with the photoelectric conversion efficiency of traditional three-dimensional perovskite materials as high as 22% or more, two-dimensional perovskite materials still have a big gap in device performance..."
"Two weeks ago, the Mohite research group published a main journal of "Nature" and prepared a two-dimensional perovskite material with a molecular structure of (n-BA)2(MA)3Pb4I13. They used the thermal spin coating method for the first time. , Increasing the device efficiency from 4.44% of the standard to 12.52%..."
"My idea is to use the isomer of n-butylamine, iso-butylamine iso-BA, to replace the position of n-butylamine in the molecular structure in the literature, during the preparation of similar two-dimensional perovskites..."
After hearing "n-butylamine" and "isobutylamine", Xu Qiu subconsciously looked at Chen Wanqing, ‘this operation seems to be familiar to the senior sister. ’
The elder sister met his gaze with a blank face, "Look at your Han Jiaying, go to Xi, what are you doing with me? ’
The two exchanged silently, and no one knew what the other was thinking.
Xu Qiu turned around and thought about it carefully. Although Feifei Wu and the senior sister had similar operations, Feifei Wu imitated the main journal of "Nature". If there are results, for example, the efficiency is 8% or 10%. It’s not too difficult to mix up an article like AM and AEM.
This is the advantage of the hot field, as long as you catch the hot spot, high-level articles will be available.
If the efficiency is further improved, 16% and 18% can be obtained, which are close to the three-dimensional perovskite system, and then cooperate with Feng Shengdong and others to engage in mechanism research and the like, and even have the opportunity to be published in the "Nature" magazine. The main journals of "Nature" and "Science" are not impossible.
Of course, this kind of thinking is enough, not very realistic...
Because the more popular the field, the more researchers and the greater the competition.
In addition, the threshold of the perovskite photovoltaic system is relatively low, and there is no need to do complex synthesis like organic photovoltaics. You can directly buy the material and mix it with a solution to make the device directly. The article cycle is usually relatively short.
When you see someone else has published an article and developed the first-generation material, in fact, they may have already secretly developed the second or even the third generation.
If it is so easy to achieve efficiency breakthroughs, there is a high probability that Wu Feifei will not be able to find out, and it has been too slow.
There is still a chance to counterattack areas involving such long periods of organic synthesis. It is still too difficult to counterattack short periods of time like perovskite.
After listening to Wu Feifei's report, Wei Xingsi nodded and said casually: "The idea is okay, hurry up and do it, are the medicines ready?"
"I bought both high-purity n-butylamine and isobutylamine last week, and they have been sent to the laboratory. I put them in the glove box." Chen Wanqing replied.
Wei Xingsi gave an "um", staring at the molecular structure on the projection screen for ten seconds, then suddenly turned his head and asked, "Xu Qiu, how did you do the light source test on Saturday?"
Xu Qiu was taken aback for a moment, and Xin said why he suddenly mentioned the light source, but he still answered normally, highlighting the workload by the way: "We have prepared nearly a hundred samples, all of which have been tested, and my data has been processed. And put it in the article."
After a short pause, Xu Qiu continued: "By the way, I have completed the draft of the NC article." Speaking of which, he was directly summoned by Teacher Wei early this morning to read the document of "Nature·Materials" , I never found a chance to tell Teacher Wei the good news before.
"Oh, so fast!" Wei Xingsi said with a smile on his face: "We will discuss your article in the afternoon. Let's talk about the two-dimensional perovskite first. Do you think this type of structure can be characterized by GIWAXS? I got some useful information. I remember that no one else has made a similar report. Wu Feifei, right?"
"Yes," Wu Feifei nodded in response, "I have read less than ten articles so far, and I haven't used GIWAXS methods."
Xu Qiu was lost in thought. He hadn't considered this aspect before, and now his brain started to rotate rapidly, and while analyzing, he said:
"In the thin film obtained by spin coating of the three-dimensional perovskite material, the perovskite crystal region has an irregular polycrystalline structure, so the GIWAXS image is a concentric ring, two-dimensional perovskite material, according to Wu Feifei’s document In summary, it should be a two-dimensional structure similar to graphene, so..."
Xu Qiu imagined that the two-dimensional perovskite material film formed two-dimensional crystal regions during the spin coating process, and imagined it as a piece of soda crackers.
After the spin coating is over, the state of the biscuits may be almost horizontal, or because they are stacked on each other and have a small angle with the horizontal plane, it is very difficult to make the biscuits stand upright, not to say that it is completely There are no biscuits erected, but from a probability point of view, there are very few such maverick biscuits.
In other words, this system is not completely disordered, so GIWAXS can detect the signal.
The idea was straightened out, Xu Qiu continued:
The stacking structure of the two-dimensional perovskite film formed by spin coating must have a certain tendency. In the GIWAXS image, there will be a crystalline signal in a specific direction than other The direction must be strong."
Both Wu Feifei and Wei Xingsi nodded and agreed with Xu Qiu's point of view.
Sun Wo nodded when he saw this, although he didn't understand it very clearly.
"Okay, next time you test the light source, Feifei Wu and Sun Wo will also prepare some samples about the two-dimensional perovskite system." Wei Xingsi decided.
After finishing speaking, Teacher Wei looked at Sun Wo and said,
After your graduation project is completed, let’s do two-dimensional perovskite. You can try the system with tin. If the system with pure tin is not easy to do, then you can. Can we make a mixture of lead and tin gradually."
Xu Qiu secretly analyzed the following, it seems that Teacher Wei intends to do a big job in the field of 2D perovskite. For a small research group like Teacher Wei, this is indeed a more sensible choice.
A simple comparison will tell you that one side is a large research group. The big boss has a number of small bosses, with a number of post-doc, and then with a number of doctoral and master students~EbookFREE.me~ dozens of people are burning tens of millions. Level funding to research a field together;
On the other side is Teacher Wei's research group, and Wu Feifei took Sun Wo two people to explore hard. The speed of their results can be compared with the large research group. It is weird that they can only find another way.
If you can’t do other people in the big field, you can do it in sub-fields, and you can drink soup. Hot fields, even soup may be AM.
Speaking of which, post-doctorate is a very important main force in the scientific research circle. After all, they are paid wage earners. According to the domestic market, it is 10,000 to 20,000 a month. It is definitely better to use than doctors and masters.
The boss asks you to study something. PhD students and master students can also talk about the conditions. Post-doctors have no right to refuse, but if you are in a hurry, you can leave the station ahead of time. The restrictions are slightly less.
There is currently no postdoc in the group, mainly because Mr. Wei has just returned to China before, and there are no articles and his influence is not high enough.
There are several high-quality articles published by Feifei Wu and Xu Qiu, and there will still be opportunities to attract post-doc post-doctors to come forward.