Chapter 107: Break through 8%

　　 Xu Qiu basically spent this week in Zhang Jiang's laboratory.
　　 On Tuesday morning, after getting the two new monomers, he voted for four reactions.
　　 There are two target products, P2FBT4T-2OD and P2FBT4T-2DT, two of each.
　　 On Tuesday night, the reaction was shut down and capped, and then Soxhlet extraction was performed with a mixed solvent. The experiment ended at 12 o'clock in the evening and stayed at Zhang Jiang.
　　 On Wednesday morning, I rushed back to the Handan campus for classes, and went back to do post-processing in the afternoon. The chloroform was Soxhlet extracted and dried. The experiment ended at 11 pm and stayed in Zhangjiang again.
　　 Everything went well, no accidents happened.
　　 After all, a total of a dozen responses have been cast in the past few weeks, and he is already familiar with experimental operations.
　　 The only regret is that Zhang Jiang’s laboratory has always been the only one. He has neither seen Chen Wanqing nor Han Jiaying, and even Duan Yun has not come over.
　　 On Thursday morning, Xu Qiu returned to the Handan campus with the fifth batch of products to verify the photoelectric properties of the materials.
　　 Prepare the solution and prepare the device.
　　 Chen Wanqing leaned against the glove box and asked:
　　 "Guess, how much efficiency can you achieve?"
　　 "Previously, there was 7%. This time the probability will be higher. Maybe this time it will be 8%."
　　 Xu Qiu returned in a hurry after synthesizing the materials. He didn't have time to test it in the simulation laboratory, so he didn't dare to say too much.
　　 "If you can get up to 8%, you will be a good student."
　　 "The specific result will be known after the test."
start testing.
　　……
　　 Unexpectedly, a good start!
　　 The first device, the efficiency is reached,
　　8.88%!
　　 This is a system based on P2FBT4T-2OD, which meets previous expectations.
　　 From the earliest PBT4T, after three generations of iterative materials, the photoelectric performance finally made a breakthrough.
　　 For a new system of organic photovoltaics, 8% is an important watershed, which means that the work has the opportunity to be published in a regional journal.
　　 And it is only preliminary results, there is still room for further improvement.
　　 The next major watershed is the efficiency of 10%.
　　 If it is realized, it will be a pioneering achievement.
　　 So far, in the field of organic photovoltaics, systems with an efficiency exceeding 10% can be counted with one hand.
　　 "This value is pretty auspicious." Xu Qiu smiled.
　　 "Yeah, you are almost 9%, let's talk about the result with Teacher Wei first."
　　 "Tell him now? Don't wait for the group meeting?"
　　 "The data is so good, he may make arrangements, or go now."
　　……
　　 218 room.
　　 After listening to the two reports, Wei Xingsi was a little excited:
　　 "The efficiency is now close to 9%?"
　　 "Still unoptimized results?"
　　 After getting the affirmative answer, he waved his hand and said quickly:
　　 "Chen Wanqing, stop your work, and work on his system with Xu Qiu first."
　　 "The three-pronged approach of device performance, various characterizations, and writing articles must be done before others."
"Ok."
　　 The two nodded, and then each received a can of coconut milk.
　　 Some time ago, Teacher Wei wanted to take out a drink, but when he reached out, he was lonely.
　　 It seems that the refrigerator is refilled now.
　　……
　　 Xu Qiu’s next main work is the three points mentioned by Teacher Wei:
　　 Continue to optimize device performance, supplement various characterizations, and write articles.
　　 For an excellent academic paper, innovation and excellent performance are indispensable.
　　 These two points are like a skeleton, supporting the entire article.
　　 But it is not enough to have a skeleton. Other characterization data are needed as evidence to make the whole system more plump.
For example, in the field of organic photovoltaics, if it involves the synthesis of new materials, you need to use gel chromatography GPC to test the relative molecular mass and polydispersity coefficient of the material. Through element analysis, the proportion of various elements in the material is obtained. To test nuclear magnetic resonance NMR, hydrogen spectrum and carbon spectrum.
After 　　 there is a series of characterization tests:
　　 Thermal characterization, including differential scanning calorimetry DSC, used to test the glass transition temperature and crystallization temperature of materials, and thermogravimetric analysis, TGA, to obtain the thermal decomposition temperature of the material.
　　Optical characterization, including light absorption spectrum UV-vis, fluorescence spectrum PL, and more advanced characterization methods-transient light absorption spectrum TA, transient fluorescence spectrum TRPL.
　　 Electrochemical characterization, using cyclic voltammetry CV, testing the energy level structure, mainly HOMO/LUMO energy level, and calculating the band gap.
　　 morphology characterization, including transmission electron microscope TEM, atomic force microscope AFM, scanning electron microscope SEM.
　　 Molecular stacking structure, including grazing incidence wide-angle X-ray diffraction GIWAXS, etc.
　　 These are all characterization methods based on polymer donor materials, or effective layer blend films.
　　 In addition, there are characterization tests for battery devices:
　　 Optoelectronic performance characterization, including the most important J-V characteristic curve, and external quantum efficiency EQE.
　　 The study of charge transport dynamics, including linear carrier boosting method CELIV, time-of-flight method TOF, and space charge limited current method SCLC.
　　 A whole set of processes is completed. If the different representation methods can be mutually confirmed and the conclusions obtained are not self-contradictory, the work is perfect.
　　 But in reality ~EbookFREE.me~ it is difficult to have such an ideal situation.
　　 On the one hand, not all researchers have a full set of characterization equipment available, such as GIWAXS and TA, which most laboratories do not have.
　　 On the other hand, the conclusions obtained by different representation methods may be different, so it is necessary to make some choices and rationally choose experimental data to discuss.
　　 Moreover, after testing so much data so hard, not all of them can be put in the text. Most of the data is hidden in the corner.
　　 This is because journals have requirements for the length of articles and the number of pictures published, and different journals have different requirements.
　　 In the field of organic photovoltaics, there are about 5 body pictures for articles in general format, and about 7 body pictures for articles in Article format.
　　 Other pictures can only be placed in the supporting information as supplementary materials.
　　……
　　 Now this work is based on P2FBT4T-2OD. Although Xu Qiu hasn't written an article yet, he has already overcome the core problem, and the rest of the work is much simpler.
　　 As for whether the device efficiency can reach 10%, it can only be determined by heaven.
　　 There will be class on Friday morning, and Xu Qiu didn't plan to go to the laboratory in the afternoon. He asked Chen Wanqing for leave on WeChat.
　　 Now the simulation laboratory has been accelerated by four times, and the weekly task points reward has doubled, which is very suitable for exploring experimental conditions.
　　Moreover, there may be other research groups doing the same research, and we must hurry up and finish the work before them.
　　 Therefore, Xu Qiu is going to find a hidden place and enter the simulation laboratory to see if the device performance can be made higher.
　　 Zhangjiang Lab is a good place to go.