Chapter 71: Instrument failure (top)

　　 After completing the SEM and XRD tests, this work on the perovskite transport layer material also took shape.
　　The remaining work is the repeatability test, stability test and article writing of the device.
　　 When two people do the same job together, the efficiency has increased by more than 80%.
　　 After discussion, the two determined the division of labor:
Sister 　　 is responsible for completing the first draft of the thesis, which is because she has more experience in writing thesis.
　　 Xu Qiu continued to experiment, and finally refined and polished the paper.
　　……
In the days after 　　, Xu Qiu repeated two batches of positive structure devices, with the highest efficiency being 10.52%.
　　 only improved a little, it seems that 11% is hopeless.
　　Inverted structure has also made a batch of devices, and the same as the results in the previous simulation experiments, the highest efficiency is only about 8%.
　　 At the same time, he also tested the stability of the photoelectric performance of the first batch of devices under nitrogen atmosphere, testing one data point every day.
　　 After a week, the maximum efficiency can still be maintained above 10%, indicating that the system has good time stability under nitrogen atmosphere.
　　…………
　　 Weekend.
　　 Because Xu Qiu's device performance data is sufficient, he did not continue to make devices, but gave the glove box to Wu Feifei.
　　 Normally, the two of them do experiments in a staggered manner, and they can make a batch of devices each day, and the test is completed.
　　 But the weekend is only half a day, so I can only make a batch of devices. Xu Qiu didn't go to join in the fun.
　　 He found Chen Wanqing and said:
　　 "Senior sister, when will we discuss the synthesis of donor materials? Isn't the team going to make a report tomorrow?"
　　 "Wait for me... half an hour, I will write down the description of the device performance." Chen Wanqing said.
"Ok."
　　 Xu Qiu had nothing to do, so he found a few new articles and started reading.
　　 half an hour later.
　　 Xu Qiu glanced at the progress of the senior sister, and roughly estimated in his mind, it was only half completed, and it was estimated that he would have to wait more than half an hour.
　　 Hey, she might have misunderstood half an hour.
　　 Xu Qiu thought for a while, but decided not to disturb her.
　　 After all, writing an article also needs inspiration. What if the elder sister is in a state of thinking like a torrent of thoughts and is disturbed by herself and loses inspiration.
　　 Continue reading the literature.
　　 Another half an hour later.
　　 Chen Wanqing saved the draft of the paper, moved her head, and said:
　　 "Xu Qiu, I'm fine, you are reading the literature."
　　 Xu Qiu glanced at the time, and sure enough, his estimate was still very accurate, he calmly said:
　　 "Yes, let's start, do you have any synthesis ideas?"
"My opinion is……"
　　 Suddenly, a shrill alarm sounded from the direction of the laboratory.
　　 "This sound, is there a problem with the evaporation device?" Chen Wanqing asked in confusion:
　　 "There is usually an alarm sound, it is the situation of forgetting to turn on the circulating water or air pump, just turn them on again."
　　 But the alarm sound continued for more than ten seconds without stopping.
　　 Xu Qiu got up, put on his lab coat, and said:
　　 "I'll go and see."
　　 "Okay, pay attention to safety, call me if there is a problem." Chen Wanqing said.
　　 Entering the laboratory, Xu Qiu saw Wu Feifei standing in front of the evaporation console, seeming to check the equipment.
　　 "Where is the problem?" Xu Qiu said.
　　 "I don't know, I have checked that the circulating water and air pumps are both activated.
　　 I wonder why there is an alarm sound? "
　　 Wu Feifei finished speaking, as if she had discovered something, she said:
　　"Wait, this is not right, molecular pump overheat protection?
　　 This is the first time this happens. "
　　 Xu Qiu also leaned over, he saw "Warning, molecular pump overheat protection" displayed on the panel of the molecular pump module, and the molecular pump's speed was 0.
　　 Looking at the barometer above, it is now 3.2E-3 Pa, and the value is slowly increasing.
　　 It seems that the molecular pump has stopped working, and only the mechanical pump is working, unable to maintain the vacuum in the evaporation chamber.
　　 He thought for a while and said:
　　 "Wu Feifei, turn off the device first, let's investigate the cause again."
　　 Wu Feifei turned off the power of molecular pump, mechanical pump and evaporation machine in turn, and the alarm finally stopped.
　　 Xu Qiu analyzed:
　　 "What I have just prompted is the overheating protection of the molecular pump. It may be a heat dissipation problem. Could it be a problem with the circulating water system?"
　　 "It makes sense, but the circulating water system has been activated." Wu Feifei said.
　　 "Well, I'll take a look inside first." Xu Qiu said.
　　The principle of the circulating water system is very simple. Its main body is a water storage tank with a cooling device inside to reduce the water temperature. There is also a water inlet and a water outlet, which lead out a pipe.
　　The water flows out from the water outlet, flows in the pipe, passes through the device that needs water cooling, uses the high specific heat capacity of the water to take away a lot of heat, and finally returns to the water storage tank from the water inlet.
　　 For this device to work normally, the water level in the water storage tank needs to reach a certain height.
　　 Because the circulating water system is placed in the gap between the console and the glove box, and there is a test bench next to it, it is not easy to get in.
　　 I usually want to turn it on, using a long wooden stick to poke its start button.
　　 Xu Qiu cut off the main power supply of the vapor deposition equipment, and carefully entered from the gap between the console and the glove box, sideways.
　　 His foot was on the ground, and he didn't feel right.
　　 Looking down, there is a pool of water on the ground, extending from the floor under the circulating water system~EbookFREE.me~ Xu Qiu hastily shut down the circulating water system and unplugged it to prevent electric shock.
　　 Then, he leaned down and looked for the leak, and found that the water was dripping from the outlet.
　　 Seeing this, he opened the lid of the water storage tank and looked inside it.
　　 The water level is already below the lower limit of normal use, and the water inside is very dirty, it should be a long time no one cleaned it.
　　 "I have found the reason. The circulating water level is too low, which prevents normal operation and cools down, so the molecular pump has overheated and alarmed." Xu Qiu said.
　　 "The water inside should have evaporated," Wu Feifei said with a sigh of relief:
　　 "The circulating water has not been changed for several months. In this case, adding some deionized water should be enough."
　　 "No, it's not just a low water level now," Xu Qiu said:
　　 "The circulating water is still leaking."
　　 Water leakage in the laboratory is no small matter.
　　 Wu Feifei brought back the breath that had just been relieved, and asked nervously:
　　 "Is the leak serious?"
　　 "Fortunately, we found out early and only missed a little bit," Xu Qiu said:
　　 "First use a water pump to pump out the water inside, and then dry the water on the ground with toilet paper."
　　 "But we don't have a pump." Wu Feifei said.
　　 "Isn't there a fish tank in Teacher Wei's office? Guess how he changed the water in the fish tank." Xu Qiu said.
　　 "But..." Wu Feifei hesitated.
　　 "If you don't need a water pump, then take a hose and use the siphon effect to out the water inside," Xu Qiu said:
　　 "I just don't know who wants to be this warrior, take the first breath."
　　 "Then I should ask Teacher Wei."