Chapter 74: Experimental ideas (below)

　　 "My previous idea was to start with a simple structure, such as improving the second-generation classic P3HT donor material and transforming it into a D-A copolymer structure." Xu Qiu said:
　　 "Just now after listening to the senior sister's words..."
　　 "Shake it?" Chen Wanqing interrupted.
　　 "That's not true," Xu Qiu said:
　　 "I just think that a stop loss standard should be set. For example, if there is no result in three months, I will decisively give up this research idea."
　　 Xu Qiu discovered that his previous scientific research experience went smoothly, which made him a little too optimistic. He hadn't considered the situation that the experiment might continue to fail.
　　 In his two works, whether it is a flexible substrate or a perovskite transmission layer, the effective layer materials used are all researched by others, and even the materials are synthesized by others.
　　Before the experiment, he was able to estimate the upper limit of the device's performance, and he only needs to verify whether his idea is feasible.
　　 But his current research field, although still under the overall framework of organic photovoltaics, is a small unknown field.
　　 In this field, he can see that someone in front of him succeeded and ran ahead of him, such as the researchers who made PTB7-TH and other materials.
　　 However, Xu Qiu and them are not on the same track. The successful experience of the predecessors cannot be fully copied, and can only be used as a reference.
　　 Considering that he has the trump card of the simulation laboratory, the experiment speed is 1-2 times that of ordinary people, and three months is about half a year.
　　 If there is no improvement after so long, you should give up, and then use the experience accumulated during this time to find new research directions.
　　……
　　 "What about the specific idea?" Chen Wanqing said.
"P3HT uses thiophene units. Generally, single or multiple thiophene units can be considered D units. I want to add an A unit to it to form a D-A structure." Xu Qiudao.
　　 "Well, as far as I know, no one has done this kind of system very successfully. If you can succeed, then you can become a system by itself." Chen Wanqing said:
　　 "However, you also need to know the risks involved. No one has reported that does not mean that no one has studied it. Someone may have studied it, but the performance is not good. The article was posted in the third and fourth districts, and we can't see it."
　　 "Senior sister, don't hit me," Xu Qiu was a little melancholy:
　　 "By the way, didn't Mr. Wei said before, do you have any ideas to simulate with DFT?"
　　 "DFT, you can really try it," Chen Wanqing said:
　　 "But to be honest, I feel that this method can only be used as a reference. There are fewer and fewer people using it, and the software hasn't been updated for a long time."
　　 "Why?" Xu Qiu asked in confusion.
　　"This is a simulation software that inputs the molecular structure, through calculations, a three-dimensional picture of the molecular structure can be simulated, and molecular orbital distribution and energy level structure can also be estimated.
　　 But it is mainly used to analyze small molecules. The polymer we made can only draw a few basic structural units and perform simulation calculations, but the accuracy of the results is not high.
　　 I usually just look at the dihedral angle. In general, the better the coplanarity of the molecule, the better the performance.
　　 In addition, the degree of conjugation of the main chain of the macromolecule can also be judged by the HOMO/LUMO energy level distribution. "
　　 "Can't you get the whole big guy in?" Xu Qiu said.
　　"Because it is a simulation calculation, the more atoms you enter, the higher the complexity of the calculation and the more computing power required.
　　 We have no overcalculation. It usually takes half an hour to count one or two structural fragments. It does not count as a month to get the entire molecule in. "
　　 Xu Qiu wondered if he could use the system to upgrade the function of DFT simulation calculation, but this is the next thing, the DFT process has not been completed yet.
　　 "Sister, how do you draw molecular structures?" Xu Qiu said.
　　 "Oh, having said so much, I forgot to teach you the most important thing." Chen Wanqing said embarrassingly:
　　"You must first download the software package from the school's genuine software, which contains a lot of software.
　　 What we are going to use is Chemdraw software, which is specially used to draw molecular structures. However, the software package is a bit big. You can use my computer to draw first. "
　　 Chen Wanqing opened the software and demonstrated while explaining:
　　" The operation is very simple, first select an ACS template, and then draw the molecular structure like a drawing.
　　The commonly used benzene ring, thiophene ring, carbon-carbon single bond and double bond have preset graphics, which can be drawn automatically with one click.
　　 The molecular structures that we usually see in the literature are basically made with this software.
　　How about the younger brother, have you abandoned your studies? "
　　 "I learned it, it looks really simple." Xu Qiu nodded.
　　 "Okay, after drawing the molecular structure, export it to a file in .cdx format, and you can perform DFT simulation." Chen Wanqing said:
　　 "Of course, it can also be opened with other software, such as Chem3D, and you can see the ball and stick model or the atom model of the drawn molecule."
　　……
　　 After they drew their molecular structures, they copied them to the USB flash drive and went to Teacher Wei's office.
　　 "How about it, is the circulating water repaired?" Wei Xingsi asked.
　　 "Fixed, the cause of the leak is..."
　　 Xu Qiu said halfway~EbookFREE.me~ Seeing Chen Wanqing winking him crazy.
　　 He has a sharp change in his mind, does the senior sister mean that?
　　He continued:
　　 "It is caused by the aging of the rubber ring. Now the rubber ring has been replaced with a new one, and deionized water has been added to the water storage tank. There is no leakage."
　　 "Just fix it, do you have anything else?" Wei Xing thought.
　　 "We are here to do DFT simulation." Chen Wanqing said.
　　 "Okay, you can do it." Wei Xing thought.
　　 Chen Wanqing opened the software and the software operation manual in TXT format, and compared the manual operation step by step. It can be seen that she is not very skilled.
　　 Xu Qiu copied the senior sister's DFT skills and software skills, and copied the big computer into the simulation laboratory.
　　DFT simulation can only calculate one molecular structure at a time.
　　 Therefore, after the software was launched, the two left.
　　 back to 216.
　　 "School brother reacted quite quickly just now, did you understand what I mean?" Chen Wanqing applauded.
　　 "At that time, it only took a few seconds. How can I think about it? I just think it would be wrong to say more, so I just briefly explained the reason." Xu Qiu said.
　　 "This is the case. There are many instruments in the laboratory, and everyone is responsible for a part." Chen Wanqing said.
　　 "I understand," Xu Qiu said, "Senior sister is responsible for the evaporation equipment."
　　 "Yes, so if something goes wrong, I am responsible." Chen Wanqing said:
　　"If the rubber ring material fails, this kind of accidental cause can still be accepted by Teacher Wei.
　　 But if he knows that it is a man-made reason, because he has not changed the water for a long time, I guess he will be scolded again.
　　 Fortunately, my younger brother is quick to respond. "