Chapter 247: 1 listen to the old fan chart

"I have a scientific research support system novel ( to find the latest chapter!
"Ring ringing."
At eight o'clock in the morning, the mobile phone alarm clock rang on time.
Xu Qiu quickly turned off the alarm clock and lay in bed for a minute. Only then was a carp struck forward and sat up.
He looked at the other two bunks, Tao Yan had already left the dormitory, and Ren Bin was still asleep.
I picked up my phone and unlocked the screen. Among the messages pushed by various applications, there was a WeChat message from Teacher Wei.
"Received, it's hard work." The other party replied with the pile of instrument pictures he took before.
Xu Qiu checked the time when the message was sent. It was around one o'clock in the morning. It was estimated that Teacher Wei had just arrived at the hotel at that time.
He did not reply to Teacher Wei, but sent Han Jiaying "Good morning", and then went to wash briefly.
After washing up, the school girl has not responded to the message. Xu Qiu judged that she should have not gotten up yet, after all, the two of them got it early in the morning last night.
So, he went to exercise and eat early.
At about nine o'clock, Xu Qiu received news from Han Jiaying:
"Good morning~"
"^(￣(oo)￣)^"
"what is this?"
"pig."
"You are a pig."
"Rebound."
"Anti-rebound."
"Stop it, get up quickly."
"Just make trouble, hum!"
Xu Qiu was chatting with the school girl while walking in the direction of Caiyi. He mainly typed, and the school girl mainly made speech. The girl’s voice was three-point lazy, three-point arrogant, four-point soft. It's just an old fan chart.
Han Jiaying didn't spend too long in bed. After all, her experiment task today is not light. On the one hand, she has to test whether the microwave reactor is easy to use, and on the other hand, she has to deal with the two reactions Xu Qiu put in yesterday.
"Get up, I'm going to wash."
"Hey, go ahead."
Xu Qiu arrived at Caiyi 216 at about 9:30. He found that the laboratory had not yet opened. He was the first to come.
He shook his head, opened the door with a card, entered the laboratory inside, and checked the 8 disposable centrifuge tubes with sample copper meshes prepared a few hours ago, each containing 2 samples of the same system.
Xu Qiu confirmed that the water in the centrifuge tube and the sample copper net was completely dried, and packed them in a plastic bag.
When he came down to the first floor of Cai, he happened to meet Sun Wo who had just cycled over, said hello to the other party, and then walked towards the aging building in a familiar way.
The TEM test scheduled for today is ten o'clock. He arrived at the TEM test room about ten minutes earlier. The students in the previous group have not left yet. They are testing the last sample.
After waiting for a while, it was finally Xu Qiu's turn.
The teacher in charge of the test was the same one last time. There were not many words. The other party briefly asked about the type of Xu Qiu's sample. He wanted to get any information, so he began to sample.
Cool down with liquid nitrogen, evacuate, turn on the camera, and start the test.
The two communicated the shooting location, took pictures, zoomed out, continued to take pictures, continued to zoom out...
Enlarge the screen, change a position, repeat the previous step.
Replace the sample and repeat the above three steps.
U disk copy data, pat and leave.
Although the final data obtained by the TEM test is a set of bitmap pictures in .bmp format, you need to manually crop and image them later, but during the test process, you can also see the images directly on the computer screen in real time.
When leaving the test room, Xu Qiu had already completed the preliminary analysis of the data in his mind.
There are four sets of conditions, and the TEM images are different:
1#, pure chloroform solvent conditions, blending with the receptor is very good, almost no accumulation area of ​​PDI;
2#, chloroform + conditions, better blending for the receptor, there is a small amount of PDI accumulation area;
3#, pure chlorobenzene solvent conditions, a certain degree of phase separation occurs to the receptor, and there is obvious PDI crystal phase area;
4#, chlorobenzene+ conditions, there is obvious phase separation for the receptor, and a large amount of PDI crystal phase area is produced.
Different solvent treatment conditions correspond to different device performance. According to the conclusions drawn in the previous simulation laboratory, 2# is the best, 1# is the second, 3# again, and 4# is the worst.
The corresponding relationship between the performance of this device and the blend morphology is in line with the general theory of blend morphology in the field of organic photovoltaics, that is, the best blend morphology of the effective layer is a bi-continuous three-phase structure, and the blend morphology of 2# The best, so the corresponding device performance is also the best.
The so-called bi-continuous three-phase structure refers to the three phase regions of donor aggregation phase, acceptor aggregation phase, and acceptor blend phase. One of the three phase regions is indispensable: among them, the two aggregation phases need to present a bi-continuous structure throughout the entire The effective layer has a scale of about 100 nanometers, which is used to generate excitons and transport free electrons and holes to the electrode; there is a blended phase at the junction of the two aggregation phases, and excitons are also produced, but the main function is to disassemble The excitons are separated to form free electrons and holes, and then they are transferred to the acceptor aggregation phase and the donor aggregation phase respectively.
In the field of organic photovoltaics, the entire photoelectric conversion process has five main steps:
Excitons are produced, the first step in the conversion of light energy into electrical energy. Photoelectric materials absorb photons and are excited to form electron-hole pairs bound by Coulomb's gravity;
The excitons diffuse and the trapped electron-hole pairs are transferred to the acceptor blend phase;
Exciton splitting, the trapped electron-hole pairs are split at the donor-acceptor interface and become freely movable electron-holes, which stay in the donor phase of the acceptor, and part of their energy will be lost during the process;
Free charge transport, driven by the built-in electric field, free electrons and holes move to the two electrodes in the acceptor donor aggregation phase;
The free charge is collected by the electrodes. In the absence of an external load, the two electrodes collect electrons and holes respectively, that is, negative and positive charges to form a potential difference. If there is an external load, a photocurrent is formed.
The three-phase structure takes on the first four of these five steps, and the importance of the morphology of the blended film is evident.
This is why the same photoelectric material is used, and the performance of the final battery device is different under different device processing conditions.
Xu Qiu left the aging building, strolled a few steps outside, came to the fourth teaching building next to him, found a classroom that was not in class, and walked in.
There were a few self-study students in the classroom, and Xu Qiu's appearance did not cause any disturbance.
Xu Qiu glanced at their textbook.
Huh, "Advanced Mathematics B".
It should be the freshman students, stay in the classroom to review after the first and second classes.
Xu Qiu reasoned inwardly, and then lay down on the seat near the door, pretending to sleep, and entered Simulation Lab II.
Based on the results of this TEM test, he got several main conclusions:
First, in the two optimal 3D-PDI systems of Xu Qiu and Han Jiaying, the intrinsic crystallinity of PDI molecules can be greatly suppressed under the conditions of low-boiling chloroform solvent treatment.
Second, the PDI non-fullerene acceptor system is different from the traditional polymer-donated fullerene derivative acceptor system. The blend morphology of the effective layer of the former is greatly affected by the processing solvent. Xu Qiu speculates that it is possible The reason is that the former is crystallization dominated by small molecule materials, and the latter is crystallization dominated by polymer materials.
Third, the solvent additives with high boiling points will prolong the time for the effective layer solution to transform into the effective layer film, thereby enhancing the crystallinity of the 3D-PDI molecules and increasing the number and size of the PDI crystal regions.
Fourth, the two main solvents of chloroform and chlorobenzene are compared. The boiling point of chloroform is lower than that of chlorobenzene. Therefore, the system of chlorobenzene solvent in the initial state is easier to induce 3D-PDI molecular crystallization to form crystal regions.
Among these conclusions, the second one provides new ideas for the following experimental optimization:
Since the blending morphology of the effective layer is greatly affected by the processing solvent, the exploration in this area should be strengthened.
Xu Qiu quickly made an experimental plan, using the pure chloroform system as the reference point (at this time the crystal area of ​​PDI is almost 0), imitating the optimized route of the previous chloroform system, and introducing various high boiling point solvents as solvent additives ( The number and size of PDI crystal regions increase).
Then, he quickly gave instructions to the simulation experimenters to explore the chloroform chlorobenzene system, chloroform dichlorobenzene system, chloroform chloronaphthalene system...
...
In the afternoon, Xu Qiu added two HOMOLUMO energy level tests of the 3D-PDI system.
Although his 3D-PDI molecules have been developed for three generations this time, Xu Qiu does not intend to split the three generations of molecules into three articles for publication like the previous PCE11 system.
On the one hand, to split into three articles, they must be published in the order of the first, second, and third generation, and there is a possibility of being cut off by others in advance.
On the other hand, this kind of development article may end up with an ordinary one area plus two second areas. The number of articles has increased, but the quality is not as good as that of an NC. Besides, there are editing or other research work. The risk of not buying it.
If you graduate with a lack of articles, it is understandable to do this, but Xu Qiu is not lacking in articles now, so naturally there is no need to do so.
After completing the HOMOLUMO energy level test, Xu Qiu put the existing characterization data in the PPT file for summary.
I don't know if I don't summarize it, I am surprised when I summarize.
He was surprised to find that the characterization data of the two optimal 3D-PDI systems of him and his school girl are now basically gathered:
Light absorption performance, including light absorption spectrum UV-vis, fluorescence spectrum PL, and transient fluorescence spectrum TRPL, are all tested;
HOMOLUMO energy level test, just finished;
Related to molecular structure, including hydrogen nuclear magnetic resonance NMR spectrum, carbon spectrum, elemental analysis ~EbookFREE.me~Sample has been sent, and the original data can be obtained after a few days;
DFT simulation, the test is complete.
Photoelectric performance, bright state and dark state J-V characteristic curve, external quantum efficiency curve EQE, the test is completed, of course, if the efficiency reaches a new high in the future, a new one needs to be drawn;
Morphological characterization, transmission electron microscope TEM, test completed.
There are only a few characterization tests that are currently lacking, such as CELIV for charge transport mechanisms, GIWAXS for molecular stacking structure characterization, and atomic force microscope AFM, and perhaps an SCLC.
It will take a day or two next week to get CELIV, AFM, and SCLC. Two weeks later, go to the light source and test another GIWAXS, and the data will be completed.
In this way, the article can be written.
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