Chapter 27: Determine the experimental plan

　　 The villain in the video makes the pipette gun superb, as if performing a stunt.
　　 It first stood still, press the pipette gun, the liquid flow inside the pipette gun flew out, and fell into a vial one meter away accurately, without leaking a drop;
　　 Then it disassembled the pipette gun into parts and spliced ​​them together, then changed to a model pipette gun, and continued to disassemble and splice;
　　……
　　 Although the operation looks wonderful, this is not the skill Xu Qiu wants.
　　 Moreover, the teaching video is very long, I guess I can’t finish it for a few days.
　　 "System, I want to learn the pipette operation during spin coating, can I?"
　　【Yes, but you need to end this teaching and restart teaching. 】
　　 "Starting again, do I have to spend another point?"
【Yes. 】
　　 "Then quit this teaching first."
　　【Get the guidance of a famous teacher, pipette proficiency +1%】
　　 500 points finally changed to 1% proficiency, which is really a pitfall.
　　 However, Xu Qiu didn't get too entangled in what has happened.
　　 He thought about it for a while, and found that the system couldn't be completely blamed for this matter, maybe he was stuck in a fixed mindset.
　　 When using the auxiliary system before, it was based on a certain experimental operation, such as spin coating, then the pipette skills used in it would be limited to spin coating.
　　 There are no restrictions this time, so what you get is a method for using pipettes covering all areas.
　　 In order to verify his ideas, Xu Qiu chose the teaching of ultrasonic cleaner.
　　Sure enough, the use of ultrasonic cleaners for material synthesis and glass bottle cleaning operations appeared in the system images, and it is not limited to cleaning substrates.
　　 In this way, all the skills he learned can be extended to other areas.
　　 can be regarded as discovering a hidden function of the system, then the 500 points spent is not too bad.
　　 "The system costs 500 points to redeem 1 level 5 100% pipetting gun teaching, and spin coating operations are limited."
　　【The exchange is successful. 】
　　 The virtual image reappeared.
　　 This time the content is all related to spin coating, but most of them are still unused skills.
　　 Xu Qiu cuts those useless skills fast forward, leaving only a few skills that are helpful to him at this stage.
　　 First of all, it is a new spin coating method.
　　 Before, he used to drop the solution on the substrate, and then start the homogenizer;
　　 The new method is to turn on the homogenizer first, rotate the substrate at high speed, and then quickly spray the solution onto the substrate.
　　A significant advantage of this spraying method is that it saves solution. The normal method requires about 60-100 microliters to coat the entire substrate at a time, while the spraying method only needs 15-25 microliters.
　　 As for the differences between the two methods in other aspects, I can only find out after Xu Qiu's experiments.
　　 In addition, when using a pipette to transfer a dense solution, there is a problem that the solution drips from the pipette tip. If you cut off the tip of the pipette tip, this phenomenon can be avoided.
　　 Xu Qiu repeated it several times, keeping the details in mind, and then withdrew from the teaching.
　　【Get guidance from a famous teacher, pipette proficiency +5%】
　　 He got up and turned on the lamp, and recorded all his harvest in the experimental notebook.
　　The effect of the fifth-order deduction of the pipette gun is not bad, so he decided to try his luck at the gluer.
　　 Moreover, the proficiency of the elder sister's glue machine is 0%, which can be directly exchanged for advanced teaching.
　　 "The system costs 500 points to redeem a five-stage 100% glue spreader teaching, and spin coating operations are limited."
　　【The exchange is successful. 】
　　 The video appeared, and Xu Qiu found that similar to a pipette, most of the skills were temporarily useless.
　　 For example: refit the glue spreading machine, install a heating plate under its platform, which can realize high temperature spin coating operation.
　　 In the end, he only learned one technique:
When 　　 spin coating, you can set up a two-stage process, first spin and spread the solution at a low speed, and then form a film at a high speed.
　　【Get the guidance of a famous teacher, the proficiency of the glue machine +5%】
　　 The points are still not spent, returning to three digits again, only 278 points are left.
　　 really come quickly, and go quickly.
　　 However, Xu Qiu felt that it was all worthwhile.
　　 Now he has thousands of inspirations in his heart waiting to be verified, and he can't wait to run to the laboratory to do a big job.
　　 Naihe is now one o'clock in the morning, and there are still classes in the morning.
　　 Hey, let's sleep well.
　　……
　　 After class on Monday, Xu Qiu read the literature, combined with the new skills he just learned, and began to design experiments.
　　 The general idea is the controlled variable method. He first lists the experimental conditions to be changed, including:
　　 Solvent. The alternatives are chloroform, chlorobenzene, and dichlorobenzene, all of which are commonly used solvents for preparing effective layers, and there are 3 kinds in total.
　　 Solution concentration. Generally, under the condition that the polymer can be dissolved smoothly, the higher the concentration of the solution, the better the quality of the film. But the higher the concentration, the more materials consumed each spin coating, and the higher the cost. A tentative concentration of each solvent is set.
　　Glue machine/speed. The rotation speed will affect the film thickness, and the film thickness of the effective layer is usually about 100 nanometers. Each kind is tentatively set at 1000, 1200, 1500r.p.m., first 600 and then 1200r.p.m., a total of 4 types.
　　Spin coating method: normal spin coating and spraying method, a total of 2 kinds.
　　 In fact, there are many variables that can be changed, including the donor/acceptor mass ratio, solvent annealing conditions, thermal annealing conditions, solvent additives, vapor deposition film thickness, and so on.
　　 But Xu Qiu is not yet willing to introduce too many variables to increase the complexity of the experiment.
　　 Now these four variables have a total of 3142=24 possibilities.
　　 is still a little bit more.
　　 He thought about it, and decided to consider the influence of solution preparation and spin coating methods on device performance separately.
　　The final plan obtained is as follows:
　　 Control group (4 groups in total):
　　Dichlorobenzene (20 mg/ml, 1:1); rotation speed 1000, 1200, 1500, first 600 then 1200; normal spin coating,
　　Experimental group A (8 groups in total):
　　Chloroform (10 mg/ml, 1:1), chlorobenzene (16 mg/ml, 1:1); rotation speed 1000, 1200, 1500; first 600 then 1200; normal spin coating. U U Reading www.udkahnshu.com
　　Experimental group B (3 groups in total):
　　Dichlorobenzene (20 mg/ml, 1:1); rotation speed 1000, 1200, 1500; spraying method.
　　 As for the choice of device structure, he found that the device performance of the inverted structure is better than the normal structure during the performance test yesterday, and the average photoelectric conversion efficiency of the two is 4.3% and 4.1% respectively.
　　 Now the main goal is to increase the efficiency to more than 5%. Naturally, the inverted structure is chosen, which is a substrate based on zinc oxide nanoparticles.
　　…………
　　Night, laboratory.
　　 Because the effective layer solution needs to be stirred overnight, Xu Qiu decided to prepare the solution first.
　　 "Xu Qiu, why are you here?" Chen Wanqing said.
　　 "I have some new experimental ideas, I want to verify it." Xu Qiu said: "Speaking of P3HT, PC[60]BM is not expensive, I will use some."
　　 "Um... it's not very expensive, it's almost a thousand per gram." Chen Wanqing said: "You use it, as long as you don't waste it."
　　 "This price is more expensive than gold." Xu Qiu said with emotion.
　　 "There are too many things in the laboratory that are more expensive than gold," Chen Wanqing said: "There are more exaggerated ones, like PTB7-TH donor materials, which cost more than 10,000 per gram."
　　 "It's so expensive, why not synthesize it by yourself?" Xu Qiu asked.
"It's not impossible to synthesize by yourself, but it may take a month or two to figure out the synthesizing conditions. This is equivalent to spending money to buy time." Chen Wanqing said: "By the way, what new experimental ideas do you have for the junior." tell me the story."
　　 "Keep it secret, I will be surprised by the time."
　　 "Then I have to look forward to it."