Chapter 143: Long-term investment?

　　 Under Xu Qiu's careful guidance, Han Jiaying spent more than 20 pieces of glass and finally got acquainted with the experimental operation of true thermal spin coating.
　　 can be seen clearly, her operation speed and experiment fluency have improved a lot.
　　 Now, except for the large circle in the center, the surface of the film obtained by her spin coating is basically smooth, and no solid particles appear.
　　 This also shows that the bumps on the film before were caused by the long time of solution spin coating, which caused the polymer to cool and precipitate, rather than the insoluble matter in the solution itself.
　　Because it is assumed that there is a problem with the material itself, no matter how to improve the spin coating technique, it will not help, only to re-synthesize and process the polymer product.
　　 During this period, Xu Qiu also found another problem, he asked:
　　 "You made the device before, did the spin coating rotate at 3000r.p.m.?"
　　 "Yes, I remember your P4T system, the best speed is 3000, I just used it directly, is there any problem?" Han Jiaying said.
　　 "Yes..." Xu Qiu said halfway, but stopped abruptly, deliberately selling it off.
　　 "What's the matter?" Han Jiaying straightened her head and waited for a long time, but he stopped talking and said anxiously:
　　 "Brother, you said..."
　　 "You can think for yourself, what will the spin coating speed affect?" Xu Qiu said.
　　 "Affect... the thickness of the film," Han Jiaying said.
　　 "Yes, besides the speed, what other factors affect the film thickness?" Xu Qiu asked.
　　 "Also, the concentration of the solution?" Han Jiaying suddenly realized:
　　 "I understand. I changed the solution concentration of P5T, but did not change the corresponding speed. I want to lower the spin coating speed of P5T, right."
　　 "bingo, this is also a direction that can be improved," Xu Qiu said:
　　 "In fact, by observing the film, you can also find that the color of the P5T film is obviously lighter than the other two P2T and P3T colors, which shows that their film thickness is different."
　　 Han Jiaying picked up a few substrates with tweezers, and after careful observation, said:
　　 "Really, I didn't notice it before."
　　 "When doing experiments, we must pay more attention to the observation of experimental phenomena. When encountering abnormal situations, we must think about the reasons behind them." Xu Qiu said:
　　" Let me give you a suggestion, especially in the beginning of the trial, it is better to set several gears for the spin coating speed, such as 2000, 3000, 4000.
　　On the one hand, it is because the speed is well adjusted, and the influence of the speed is usually obvious;
　　 On the other hand, the concentration of each prepared solution will change with the use or the passage of time. "
　　 "Okay, I remember it." Han Jiaying said.
　　 "Okay, other steps, I haven't seen the problem for the time being, your overall performance is still good, continue to work hard."
　　 At the end, Xu Qiu did not forget to encourage her undergraduates.
　　 To encourage others, the cost is almost zero, but to others, sometimes it is precious.
　　 "Hmm." Han Jiaying nodded seriously.
　　……
　　 Continue the experiment.
　　 After Han Jiaying solved the big problem of the real-hot spin coating technique, she spin-coated the effective layer on the zinc oxide substrate, and she did not encounter any problems.
　　 The subsequent vapor deposition was also very smooth.
　　 However, after the evaporation is over, it is already close to five o'clock.
　　 The device test will definitely be impossible within half an hour.
　　 It looks like I have to work overtime again.
　　 Xu Qiu has been looking at Han Jiaying today, without writing a word of his article.
　　 I had no choice but to comfort myself and help school girls, which is a long-term investment, worth it!
　　 "How do we solve dinner, order takeaway?" Xu Qiu asked.
　　 "For dinner, how about I invite brother to eat out?" Han Jiaying suggested.
　　 "Why is this so embarrassing that it will cost you money... Where are we going to eat?" Xu Qiu said.
　　 Han Jiaying was amused by him, thought for a while, and said, "Little North Kingdom."
　　 "Okay." Xu Qiu agreed.
　　 He has never heard of the name. It is probably not a Sichuan restaurant, but when someone treats guests, it is natural that there is nothing to choose from.
　　 Han Jiaying stared at the evaporated substrate and said:
　　 "Which film is better to start with?"
　　 "Let's pick the P3T system with the highest efficiency last time. The experimental conditions haven't changed much this time. The probability is still the highest." Xu Qiu said.
"it is good."
　　 Han Jiaying took the substrate, connected the source table, opened the software, and started the test.
　　5.88%, 5.96%, 5.93%,...
　　 The highest efficiency is 5.96%!
　　 Seeing this result, Han Jiaying looked excited and said:
　　 "Brother, 6%, close to 6%."
　　 Compared to the previous 4%, the improvement is still considerable.
　　 Moreover, this is a preliminary test, and then continue to optimize, it is still possible to achieve 7% or even 8%.
　　 As for the higher value, it is not yet clear whether it can be achieved.
　　 "Sister, congratulations, I booked an article in advance." Xu Qiu said.
　　 "Really? Can you post an article?" Han Jiaying couldn't believe it.
　　 She has read few literatures, and she is still not sure about the status of her current experiments.
　　 I only know the efficiency of the Xu Qiu system before, but it has reached 10%. Can she also post articles with this 6%?
　　 "Yes, currently in the field of organic photovoltaics, 6% is considered a threshold," Xu Qiu said:
　　 "You have reached the threshold now. If you can achieve 7% or 8%, it will be more stable."
　　 "Great, thank you brother." Han Jiaying said.
　　 This thank you is from her heart.
　　 She is not stupid, she soon figured out ~ EbookFREE.me~ Even if she can post articles, it is actually Xu Qiu's main contribution.
　　 gave her three derivative materials with molecular structures similar to P4T.
　　 The foundation of P4T is there, even if the luck is bad, there will always be one or two materials with good performance.
　　 Even if it does not reach 10% of P4T, it is not difficult to reach 6% or 8%.
　　 In addition, Xu Qiu taught her everything from experimental ideas to experimental operations. Only the specific experiments were done by herself.
　　 "Or, brother, we are one..." Han Jiaying tentatively said.
　　 Seeing Xu Qiu not speaking, she said again:
　　 "Or I can take a second job."
　　 Xu Qiu was a little helpless, Han Jiaying was like this, and Chen Wanqing was also like this before, and everyone was so polite to him.
　　 Isn't it just a second district article?
　　He didn't give the article casually. The senior sister is repaying her for her guidance. The senior sister here is a long-term investment.
　　 "You can use this job to practice your hands. As soon as it is given to you, it will be treated as a meeting gift for you." Xu Qiu said:
　　 "Now I have no shortage of articles in the second district. I have two more to post next."
　　 "Really baa," Han Jiaying said happily: "Then I will invite brother to dinner another day?"
　　 "Okay, that's it." Xu Qiu said.
　　 Continue testing.
　　 Another sample of the P3T system measured a higher efficiency, reaching 6.14%.
　　 P2T system, the highest value is only 2%, while the P5T system, the highest value is also increased to 5%.
　　 It seems that P3T and P5T have the opportunity to split into two articles and post.
　　 Is it just too watery?
　　 This question, let's think about it again.