Chapter 43: Explore etching conditions

　　The school and department set the time of the summer camp for the research institute on July 27 and 28.
　　 This arrangement takes into account the graduate students from other schools. They will come to the school on the 27th, and then the department will take them around the campus of the Magic University, and arrange a trip to the Bund in the evening.
　　 Our graduate students can also sign up for the 27th play activity.
　　 However, Xu Qiu didn't plan to join in the excitement. Although he is not a native of Magic City, he went to the Bund three times in three years of university.
　　 28th, the department will organize all graduate students to conduct interviews.
After 　　, the department will contact each student individually to confirm whether each student's intent is to be an academic master, a professional master, or a direct Ph.D.
　　 Finally, the list of candidates to be admitted will be announced at the beginning of the next semester.
　　 The holiday time for the research group is from August 1st to August 15th, a total of two weeks.
　　If the ticket or air ticket is not easy to buy, you can also talk to Teacher Wei, advance or delay a few days.
　　 As for undergraduates like Xu Qiu who are in the third year of internship, even if they don’t go to the laboratory to do experiments during the summer vacation, it’s ok.
　　 But he finally decided to spend only two weeks of summer vacation and arrange his vacation according to the time of the laboratory.
　　…………
　　 After the exam, Xu Qiu rested in the bedroom for a few days.
　　 During this period, he suspended the use of the simulation laboratory.
　　 Although the simulation laboratory is more convenient, from the point of view of its current functions, the cost-effectiveness of spending points here is still somewhat low.
　　 It is better to wait for the permission level to increase, unlock new features and then use the points.
　　 Until July 15th, on Tuesday, Xu Qiu returned to the laboratory.
　　 In the laboratory, Duan Yun is still immersing himself in the codeword writing the paper. After the paper is submitted, Feifei Wu began to do experiments, and Chen Wanqing is also working on PTB7-TH-based devices.
　　 The two glove boxes became busy.
　　 Fortunately, Xu Qiu is currently preparing to do a flexible substrate project. The problem of ITO etching needs to be solved first, and the glove box is not needed for the time being.
　　 "Xu Qiu, I have finished the exam, how did the exam go?" Chen Wanqing said.
　　 "It's okay, there should be little change in the grade point this semester," Xu Qiu said, "Sister, have the experiment been done smoothly recently?"
　　 "Thanks to your reminder, now based on the PTB7-TH device, the efficiency can reach 10%," Chen Wanqing said:
　　 "I'm thinking about how to make something new recently. After all, this system has been reported many times by researchers, and I can't publish articles with this 10% efficiency.
At the group meeting yesterday, Feifei Wu was doing a literature report. I came up with an idea to combine the perovskite material she made with mine. I don’t think anyone else has done this before. After all, perovskite material It has only just emerged. "
　　 "But I haven't found a suitable entry point yet, do you have any ideas?" Chen Wanqing looked forward to it.
　　 "Why ask me, I haven't done perovskite." Xu Qiu couldn't laugh or cry.
　　 "The previous spraying method of P3HT, the thermal coating method of PTB7-TH and the additives are all up to you." Chen Wanqing said.
　　 "So you want to come to me to try your luck?" Xu Qiu said.
　　 "Yeah." Chen Wanqing nodded.
　　 "Well, let me think about it."
Xu Qiu had a headache. In the previous two times, one was obtained by the fifth-order deduction of the system, and the other time he did an experiment in advance and figured out the experimental conditions. Now he is facing a completely unfamiliar field. opinion.
　　 But he still thinks seriously. Organic photovoltaic devices are mainly composed of electrodes, transmission layers, and effective layers. The newly added perovskite materials are definitely not used as electrodes, so they are used as transmission layers or effective layers.
　　 Thinking of this, Xu Qiu asked: "Should the perovskite material be used as a transmission layer or an effective layer?"
　　 "Of course it is effective..." Chen Wanqing paused, and suddenly said: "Yes, perovskite can be used as the transmission layer. Look for a perovskite material with a wide band gap that basically does not absorb visible light."
　　 "School brother, your idea is good, I will wait and discuss with Wu Feifei." Chen Wanqing said excitedly.
　　 "I just mentioned it casually." Xu Qiu said in embarrassment.
　　 Seeing that the elder sister was immersed in the inspiration he had just gotten, he took the initiative to leave: "Come on, elder sister, I'm going to try to etch the PEN substrate."
　　 "Okay, go ahead."
　　…………
　　 Entering the laboratory, Xu Qiu first took out a whole roll of PEN substrate.
　　 Then use the ITO glass substrate as a template to cut out a dozen PEN substrates of the same size as the glass substrate.
　　 After tearing off the protective film on the PEN substrate, you can see a layer of blue-violet ITO film on its surface.
　　The next question is how to get a specific ITO pattern.
　　 The etching solution is indiscriminately attacked, so if you want to obtain a specific pattern, you must protect part of the ITO.
　　 The method Xu Qiu first thought of was to stick the pattern part with tape, and then soak the substrate in the etching solution.
　　 He went to the toolbox and took out 3M electrical tape, sealing tape, and a milky white tape of an unknown brand, while double-sided tape and bubble gum were directly excluded.
　　 Three kinds of adhesive tape are respectively pasted patterns on the cut PEN substrate.
　　 After that, Xu Qiu went to the reagent cabinet to take out the concentrated hydrochloric acid and zinc powder, and went to the mini fume hood in the laboratory. UU read www.uukānshu.com
　　 Turn on the exhaust system of the fume hood to prepare the etching solution.
　　The concentration of concentrated hydrochloric acid of Sinopharm is 12 moles per liter, and it needs to be diluted to 2 moles per liter, which is 2M, before it can be used.
　　 This concentration does not need to be particularly precise, so he directly took a disposable dropper for operation.
　　 First draw 2 ml of concentrated hydrochloric acid and add it to a 20 ml centrifuge tube, then slowly add 10 ml of deionized water dropwise, mix well, and obtain a 2M concentration of dilute hydrochloric acid.
　　 Then, Xu Qiu took out three disposable plastic cups, poured in an appropriate amount of 2M dilute hydrochloric acid, and covered the bottom of the plastic cup.
　　 He didn't pour the zinc powder right away, but put the PEN substrate into the plastic cup first. The dilute hydrochloric acid just covered the substrate.
　　 After waiting for a minute, Xu Qiu picked up a piece of substrate and found that the ITO film on it had no traces of etching.
　　 During this process, the three cups of solution did not change.
　　It seems that it is impossible to etch without adding zinc powder.
　　 Xu Qiu put the substrate back into the cup, and then scooped two spoons of zinc powder into each cup.
　　 The zinc powder reacts immediately when it encounters hydrochloric acid to generate hydrogen gas, and a lot of bubbles are emitted.
　　At the same time, the odor of hydrogen chloride molecules in the hydrochloric acid also exudes. Xu Qiu hurriedly pulled down the fume hood door after smelling it.
　　 After two minutes, the reaction almost stopped, and there were no more bubbles in the cup.
　　 Xu Qiu opened the fume hood again and rinsed the PEN substrate with a deionized water washing bottle.
　　 However, he found that part of the tape had fallen off, and the hydrochloric acid penetrated into the tape area, causing the ITO that was protected under the tape to be etched.
　　 In comparison, 3M electrical tape has the strongest protective ability, but there is still some acid infiltration.
　　The experiment failed.