Chapter 241: By mistake

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Back to 216, Xu Qiu went to the glove box to prepare two solutions, based on his third-generation 8 series and Xuemei's B4T series, the two most efficient 3D-PDI systems. During the preparation, the solution concentration increased by about 4%, and he planned to adopt the new strategy introduced by the solvent additives just formulated today.
Subsequently, he used the zinc oxide prepolymer solution left by the school Sunday and the cleaned ITO substrate, spin-coated 20 zinc oxide substrates, and placed them on a 200°C heating platform for high-temperature annealing.
In the afternoon, Han Jiaying and Chen Wanqing left on the school bus and went to Zhangjiang for a synthesis. Xuemei’s main job is to synthesize her second-generation B3TB4T materials in large quantities, and at least get the final product of more than 200 mg; the newly bought 1,3-indenedione (unit A) is still on the way, she plans First, prepare the aldehyde group reaction of D unit, and when the A unit arrives, it can be directly synthesized.
At around 1:20, Xu Qiu entered the laboratory to prepare a batch of devices.
Sun Wo seemed to have the idea of ​​spin coating, but when he saw Xu Qiu, he took the initiative to avoid the glove box.
Xu Qiu nodded friendly towards Sun Wo, transferred the annealed zinc oxide substrate into the glove box, and then carefully added the two bottles of solution using a new strategy, then gently shake the bottle for one minute to disperse evenly in the solution. Clean the glove box atmosphere for 5 minutes, then enter the glove box again and start spin coating.
This time, he directly used the best conditions found in the simulation laboratory as his experimental conditions.
During the spin-coating process, Xu Qiu was very serious and focused, trying to capture the flash of inspiration from the last experiment.
However, after the spin-coating of 20 devices was completed, there was no sensation of inspiration.
Xu Qiu had no choice but to shrug her shoulders helplessly, transfer these components to the evaporation chamber, and begin evaporation.
While waiting for the vacuum to drop, he did not idle either. He took about 1 mg of each sample of more than 20 products and intermediate products brought back by the school girl, put them into a nuclear magnet tube, added deuterated chloroform to dissolve, and went to the aging building. A sample was sent to test the NMR spectrum.
Coming back from the aging building, he continued to vaporize and test non-stop.
In the end, the highest efficiency of this batch of devices reached 7.35%, and the school girl’s system also reached 6.50%.
Seeing this result, Xu Qiu sighed. Not surprisingly, he did not expect to reach the highest value of 7.50% in the simulation laboratory at one time, as long as it can be close to this value.
After all, the highest value obtained in the simulation laboratory this time is different from the past. In the past, it may have been the highest value among several or more than a dozen experimental results, but after repeated optimizations this time, it was the result of nearly a hundred experiments. .
It looks like 7.50%, but in fact it is about 7.30±0.20%.
This time, only 10 of the 20 devices belonged to Xu Qiu. The number of samples is not too large. As long as the result falls near 7.30%, it is considered normal.
...
In the next two days, Xu Qiu made two batches of devices in succession. At the same time, he sent samples of more than 20 products and intermediate products for elemental analysis.
These involve basic characterization tests of molecular structure, and all intermediate products must be carried out;
Characterization methods for effective layers or devices such as light absorption, energy level testing, and microscopic morphology do not need to be exhaustive, as long as the final product is considered.
After making three batches of devices for three days, Xu Qiu finally repeated 7.48% and 6.60% efficiencies in reality.
When he was doing the experiment, he was always thinking about whether there is any place to improve it, especially for some things that are difficult to do in reality, and use the optimization methods that can be done in the simulation laboratory.
He really found a way-the simulation experiment system II can be used to optimize the transmission layer of the battery device.
In reality, for the transmission layer, the usual practice is to do a wave of exploratory experiments to confirm a set of experimental conditions before starting the experiment, and to fix it for long-term use.
On the one hand, in reality, if you want to optimize the transmission layer, such as changing the film thickness of vapor-deposited molybdenum trioxide, you must re-evaporate the device every time you change the conditions. In addition, the experimental data will fluctuate, and a large amount of data can be confirmed Optimal conditions, the time cost of the experiment is very high.
On the other hand, the transmission layer has little effect on device performance. After a set of general conditions are established, it may not be able to exert 100% effects in all systems, but it can stably exert more than 95% effects under most systems. This is enough, there is no need to re-explore every time a system is changed.
But Xu Qiu has Simulation Lab II, which can perfectly solve this problem. With dozens of evaporation machines working at the same time, the conditions can be found clearly in one wave, and it does not cost too much system integration.
I didn't expect this before. The main reason was that Xu Qiu didn't do device optimization work for a long time after opening the simulation laboratory II. In addition, it was also affected by the fixed mindset.
Now that his thoughts are open, Xu Qiu instantly diverges, thinking of many ideas:
For example, in addition to the optimization of the film thickness of molybdenum trioxide, the preparation conditions of zinc oxide can also be explored, including film thickness, annealing temperature, annealing time and other preparation processes.
For another example, you can try a device with a positive structure. Although in most cases the performance of an inverted structure is better, and Xu Qiu has become accustomed to using an inverted structure after long-term experiments, and it is more convenient to prepare, but it does not rule out exceptions. Possibility.
In addition, there are some new transmission layer materials developed by other researchers, such as PFN and PDIN, which have been commercialized and are not expensive. You can buy some from the optoelectronic materials company in Shenzhen.
The film thickness of the metal electrode does not need to be optimized, because as long as the film thickness exceeds a certain threshold to ensure that the device does not break, the specific thickness is not important, even if it is evaporated to a thickness of 1000 nanometers, there is no difference from a thickness of 100 nanometers. On the contrary, the resistance may increase. It is not impossible that the efficiency is reduced by 0.01% if it is 10 times larger.
Of course, the type of electrode still needs to be considered. There are three commonly used electrodes, and the work functions of gold, silver, and aluminum are different.
However, with previous exploration experience during PCE11, Xu Qiu has explored this aspect, and the best electrode in the current system is silver.
Based on these ideas, Xu Qiu gave instructions to the simulation experimenters:
Based on the existing optimal experimental conditions, optimize the processing technology of the two 3D-PDI series battery devices. The first priority is to control the film thickness of molybdenum trioxide, the second priority is to control the preparation conditions of zinc oxide, and the third priority Level is an attempt at a positive structure device, and the fourth priority is to introduce a new type of transport layer material (there is no material for the time being, it is freezing).
"In general, this time it was a blunder. After three consecutive days of practice, the previous flash of inspiration was not caught, but new experimental inspiration was generated." Xu Qiu concluded by himself. Then he said with emotion:
"It's just that the consumption of points is a bit fast. It's a little bit stretched to get an account of 3000 per week. Fortunately, I have accumulated a lot of foresight before, and it is still enough for the time being. I hope that I can make up for it next time the authority is upgraded."
...
Wednesday night.
Because Wei Xingsi is going abroad this Thursday, he is still busy these days. After the weekly group meeting, he basically didn't care about the laboratory, and was always busy with his own affairs.
Now I am finally ready, and when I am free, I plan to have a heart-to-heart talk with the students and learn about the latest experimental progress.
Feifei Wu was the first named, but it didn't take long for her to enter 218, about three minutes later, she came out of the office.
"Xu Qiu, Teacher Wei is looking for you." Wu Feifei said, her expression looked quite happy.
"Okay." Xu Qiu nodded in response. Today's experiment has been completed and there is nothing to do. At this time, he is reading the literature, trying to find some inspiration from it.
After hearing Teacher Wei's call, Xu Qiu immediately put down the literature, got up and went to 218, but he was slightly surprised and sorted. Generally, Duan Yun was the second one, but it didn't matter.
"How about the experiment?" Teacher Wei sat at the desk, leaning on the back of the swivel chair, seemed a little tired, and said lazily.
"I made three batches of devices this week. Based on my third-generation 8 series and Han Jiaying's second-generation B4T series 3D-PDI, the current highest efficiency..." Xu Qiu deliberated and kept one hand as usual. 7.03% and 6.38%, there is still room for further improvement." By the way, I also answered the questions that Teacher Wei might ask next.
"7%!" Wei Xingsi's eyes lit up, and he straightened up. Then he stared at the pen holder on the desk, lost in thought, and began to tap the table with his fingers unconsciously. He didn't know that Xu Qiu hid his hand. If you consider the normal situation, the chance of a breakthrough in device efficiency in just three days is actually not great, so he was a little surprised by the news.
After a while, Wei Xingsi suddenly looked at Xu Qiu and said, "If I remember correctly, the current world record of the PDI system is about 8%."
"Yes, the current highest efficiency is 7.92%," Xu Qiu nodded in response, then explained in detail:
"It was a work just published last year. The trimers and tetramers of PDI are connected by vinyl groups to form fused rings. The donor material is PCE10. That article was published on AM."
Xu Qiu now wants to challenge the efficiency record of PDI. I have read the original article many times and remember it very clearly. This article also gave him experimental inspiration. When designing 3D-PDI molecules, he used the inspiration source of fused cyclization. It is here.
"Do you have the confidence to surpass them?" This is a question, but Wei Xingsi said affirmatively.
"I try my best." Xu Qiu didn't say too much.
"Good!" Wei Xingsi smiled and nodded, "If we can improve the efficiency of the device, we can make a big article."
Wei Xingsi's heart already has a bottom. If Duan Yun says "I try my best", don't think about it, most of the work will be cool, because Duan Yun likes to brag, one day he doesn't blow, it means that the problem is very big; and Xu Qiu is relatively stable, and being able to say this means that he is at least 50% sure.
Different people say the same things, and they mean different things. As a tutor, Wei Xingsi thinks that he is more accurate in his grasp of the students' ability, character, and behavior style.
After a pause, he continued to ask: "By the way, what is the result of TRPL?"
"It's okay. I got a preliminary conclusion before. The fusion of 3D-PDI molecules can significantly improve the ability to split excitons between receptors." Xu Qiu said.
"Yes, if you add partial theoretical research, you might even have a chance to hit Nature, NC, or Science's new sub-journal Sci.Adv." Wei Xingsi said with emotion:
"In the field of PDI, there have been no articles in the Nature and Science series for many years."
Xu Qiu gave a hum and did not respond much.
In fact, except as early as 2001, when PDI was used as an acceptor material in the field of organic photovoltaics for the first time, and a main journal of "Science" was published, none of the articles published in the PDI series in these years was related to "Nature" and "Nature". "Science".
In that "Science" article, R.H. Friend is one of the authors, and he is one of the pioneers in the field of organic photovoltaics.
The specific content of the article is an organic photovoltaic device based on PDI acceptor, under 490 nm light conditions, a photoelectric conversion efficiency of 1.95% was obtained.
This is just a slag-like result now, not to mention the low efficiency, the illumination conditions are only monochromatic light, and they are not data under the standard solar spectrum. It was a breakthrough development at the time, which means that the researchers finally An alternative to fullerene derivatives has been found.
Unfortunately, for so many years, the PDI series has been unsuccessful. AM, EES, JACS, Angew (German Applied Chemicals) and other materials and chemistry top publications have published more than ten articles, but one is related to Nature and Science. There are no sub-publishes, even for the "Nature" kid magazines like NC.
In this case, it's like some researchers play in a small circle but can't get out of the circle.
In the final analysis, non-fullerene receptors are only a subdivision of the large research field of organic photovoltaics, and PDI is a subdivision of the non-fullerene system.
Unless you can achieve breakthroughs in subdivisions, such as breaking the total record of photoelectric conversion efficiency (12%) in the entire field of organic photovoltaics, the meaning is naturally different.
Break the record of the PDI system NB?
Naturally NB.
But there is a higher record above.
just like:
Is the million-dollar net worth? so so.
Ten million net worth is not great? Also improvised.
Is the billionaire net worth? This is amazing.
But there are billionaires on it.
Therefore, now having the opportunity to seek a sub-journal of "Nature", "Science", (NC), or Sci.Adv. (SA), is also a big improvement.
Of course, in academia, different researchers in different fields have biased the positioning of different journals, just like the dispute between AM and JACS. Whether the conversion ratio is 1:1, 1:2, 2:1 or other, no one Can speak clearly.
Some people look down on NC, think there are a lot of watered articles on it, and they have to charge a lot of page fees, not as good as AM, not as good as JACS, but if you ask them to try to water on NC, they will wither instantly.
Relatively speaking, in the field of organic photovoltaics, there must be more research groups that can irrigate on AM and JACS than those that can irrigate on NC.
As for the comparison between NC and SA, relatively speaking, NC is an old journal and relatively stable, while SA is a new journal, with a betting element in it. It is difficult to say clearly what the future will look like.
Therefore, Xu Qiu still prefers NC.
This is a lesson from the past ~EbookFREE.me~ Just like when Sci.Rep. (SR), a sub-published by "Nature", was just published, many people thought it was NC's second place. They voted for many good articles and waited for appreciation.
Now that SR is out of the district, it is the third district of SCI. People are immediately dumbfounded, and they are all embarrassed to introduce their SR work to others.
However, these are still in the imaginary stage for Xu Qiu.
When the device efficiency reaches more than 8%, it will have a chance to make this reality.
PS: Last week, on the basis of 6,000 words updated every day, more than a few hundred to more than a thousand words, the accumulation of less, more than 4 thousand words in a week, has been 100 monthly tickets and 4 of the 2000 recommended votes last week Thousands of Canadians paid it back.
The author is very disciplined, right? Ask for a wave of monthly and recommended tickets.
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