I Have a Research Support System

Next, it was Chen Wanqing's turn to report.

At the group meeting last week, she and Sun Wo were still "difficult brothers and sisters", but now it is completely different.

Because she got the device data that Xu Qiu helped her on Friday, the highest efficiency of the PCE10:IDT-ICIN system has reached 3.81%, which is close to 4%.

With the data in hand, the whole person instantly hardened a lot.

In addition, she also supplemented the basic light absorption spectrum, fluorescence spectrum and other tests, the number of pages of the PPT for the group meeting directly reached eight pages, and the workload was not to mention.

Wei Xingsi was also a little surprised. Before that, Chen Wanqing had been looking forward to the future at the group meeting for more than a month, listing the experimental plan, and there was almost no progress. He was still in the photoelectric conversion efficiency of 1% for the device performance of Chen Wanqing's A-D-A system. Unexpectedly, it is suddenly close to 4% now.

Seeing that she didn't play the outlook part this time, Wei Xingsi asked curiously, "What are your plans for the future?"

Chen Wanqing talked confidently: "I am going to complete the basic characterization of this material first. After all, it is a new structure, and the efficiency is not low now, and there may be room for optimization. Moreover, I noticed that IDT-ICIN The main light absorption range of this material is between 500-800 nanometers, and it has a great overlap with the PCE10 donor material. I consider whether to try another donor..."

"Replace the donor material," Wei Xingsi interrupted suddenly, "Xu Qiu, what do you think?"

"I think Senior Sister Chen Wanqing's idea is feasible. You can try other polymer donor materials with wide band gaps." Xu Qiu replied.

On Friday, he guided the senior sister to measure the light absorption spectrum first, the purpose is to make her notice the overlap of the light absorption range of the receptor and the receptor, but she did not expect her to be enlightened quite quickly.

Wei Xingsi thought about it for a while, then nodded and said, "Okay, but polymer donor materials with wide band gaps do not fit the traditional fullerene system after all, and there are not many types of them. You can check a few photoelectric companies to see if there are any If there is no commercial channel, if it doesn’t work, you can buy the monomer and synthesize it yourself.”

Xu Qiu didn't answer. He also felt that from a long-term perspective, self-synthesis must be the best choice, but now the organic trio has their own division of labor, and there is no free hand, so they can't compete with Wu Feifei again.

Chen Wanqing suddenly said: "I remember that the photoelectric company in Shencheng sent a sample of the polymer donor. It seems that there is a wide bandgap FTAZ material."

After finishing speaking, she looked at Xu Qiu as if asking questions, Xu Qiu pretended to think about it for a few seconds, and agreed: "There should be some, I'll look for them when I go back."

"It would be best if there are ready-made materials," Wei Xingsi said with a smile, "Of course, the main focus should be on the PCE10 system, see if we can improve the photoelectric performance, the best efficiency can be 5 More than %, so you can try to hit AM or JACS."

Xu Qiu gave a "hmm", nodded on the surface, but complained silently in his heart, "It is not easy for the PCE10 system to break 5%, but the PTAZ system has now broken through 5%, reaching 5.48%, and even has a chance to break 6%. , breaking the world record of the current A-D-A system. '

However, he could also understand Teacher Wei's thoughts.

For Mr. Wei, PTAZ is an unfamiliar system. Although it is complementary to IDT-ICIN light absorption, the upper limit of photoelectric performance is theoretically higher, but in reality, we can only wait until the photovoltaic device is prepared and tested. We know, but the PCE10 system is a system whose performance has been verified.

After all, the light absorption performance of the effective layer is not the only factor affecting the photoelectric performance of the device, but compared with the relatively "virtual" and microscopic concepts such as energy level structure, blending morphology, and charge transport, the light absorption performance is relatively "Real" is relatively intuitive, and can be obtained by directly testing the light absorption spectrum of the material.

In fact, the light absorption performance mainly determines the upper limit of the photoelectric conversion efficiency of the device. According to the Shockley-Queisser efficiency limit theory, the single-junction solar cell of the inorganic system, when the band gap of the photoelectric material is about 1.2-1.4 electron volts , the photoelectric conversion efficiency is the highest, and the upper limit is about 33%. At this time, the battery device can absorb light with a wavelength of less than 1000 nanometers, covering most of the solar spectrum.

However, due to the characteristics of exciton absorption in organic photoelectric materials, the light absorption performance of the material varies with the light wavelength as a peak curve, and there is a main light absorption range.

For example, the organic polymer donor PCE10 material with a band gap of about 1.6 electron volts, the main light absorption range is about 550-750 nanometers, and the absorption ability is relatively weak for light less than 550 nanometers, so it is blue-purple .

For another example, the non-fullerene acceptor PDI material has a band gap of about 2.1 electron volts, the main light absorption range is about 400-600 nanometers, and hardly absorbs red-orange light, so it is red-orange.

When other factors are not considered, for a photoelectric material of 1.6 electron volts, if it is an inorganic material, the main light absorption range is less than 750 nanometers, and the theoretical limit of efficiency is about 30%;

If it is an organic material, if it is a system with complementary light absorption, for example, the main light absorption range is 300-750 nanometers, the upper limit of efficiency may drop slightly and remain at about 28%;

However, if the light absorption is not complementary and the main light absorption range is 500-750 nm, the upper limit of the efficiency will further drop to 25%.

Of course, the 28% and 25% here are just examples. Applying different theoretical models, the calculated results are also different.

In any case, for non-fullerene system devices whose efficiency is only 4% or 5%, the theoretical efficiency of 20+% is still very far away.

The main factors that hinder the efficiency are relatively "virtual" and relatively microscopic factors such as energy level structure, blending morphology, and charge transport.

These factors cannot be quantified.

This is also the reason why Xu Qiu and the others will do a wave of device testing first every time they synthesize a material, and it is also the reason why Teacher Wei tends to study the PCE10 system first.

Materials science, in the final analysis, is a discipline of trial and error.

After Chen Wanqing's report was over, Xu Qiu was waiting to get up to take over.

Wei Xingsi raised his hand, interrupted his movement, and said, "Xu Qiu, you don't need to talk about it. After the group meeting, you can stay for a while and show me your article again."

"Okay." Xu Qiu responded with a nod, feeling a little regretful in his heart. The PPT for the group meeting was done for nothing, but he was relieved to think that he didn't spend much effort. He just copied and pasted the few words used in the article. Paste a picture into the PPT template of the group meeting, and it will be done in less than three minutes.

Speaking of which, Xu Qiu and Han Jiaying's daily dating project this weekend is to find a vacant classroom, sit side by side, and write about it.

Up to now, Xu Qiu has completed the references and supporting information, and only needs to get the experimental data of GIWAXS and TAS to finish. The progress of the school girl's article has also advanced by about 10%.

Finally, Jiaying Han reported her work progress: "...the current highest efficiency is 7.5%...the basic characterization is basically completed...about 30% of the article is written...now I am mainly developing the third-generation 3D-PDI material..."

Because her 3D-PDI system is similar to Xu Qiu's, Wei Xingsi did not interrupt her question when she was speaking.

After the lecture, Wei Xingsi gave a few words of encouragement at first, and then asked, "How is the development of the third-generation material for this B4T series?"

"The progress is over halfway, and the product should be available next week." Han Jiaying replied.

"Okay." Wei Xingsi paused, then suddenly looked at Chen Wanqing, and asked, "When is the light source test?"

"Next Saturday, from 9 am to 9 pm, I have completed the safety audit on Wednesday." Chen Wanqing answered.

"The three of you should go?" Wei Xingsi asked.

Xu Qiu, Chen Wanqing and Han Jiaying looked at each other and said together, "That's right."

Wei Xingsi nodded, and continued to order: "Han Jiaying, try to make your third-generation material before the light source test, otherwise you will have to wait a long time if you miss this time."

"No problem." Han Jiaying nodded.

"However..." Wei Xingsi changed the subject: "Currently, I mainly focus on your current article. Since the publication of that JACS article, I haven't seen any new articles on the 3D-PDI system. I guess it won't be long. With that, we still have to speed up the progress and catch up with others.”

"Yeah." Han Jiaying also understands that although her current job is less about AEM, there is a high probability that she can post AM, but before the article is written, submitted, or officially included, there are variables. Isn't the article of Yan Hu's research group killed by the senior brother?

Wei Xingsi took a sip of tea, suddenly smiled and said, "We have raised the efficiency threshold of the 3D-PDI system so high at once, it will be difficult for others to publish good articles."

Xu Qiu deeply thinks that the efficiency of the first 3D-PDI system is only 4%. If Xu Qiu’s second and third articles directly reduce the efficiency to 7% or 8%, then others will take the results of 5% and 6%. , I had the opportunity to invest in journals in the first region, such as AEM, but now I may only be able to vote for the journals of the weaker region JMCA, CM, or even ACSAMI and AELM in the second region.

Because of this, some research groups will suppress articles, so that the progress of a field shows a slow upward trend, such as the efficiency of 8%, 9%, 10%, 11% all the way up, instead of jumping directly from 8% to 11% , the former can be filled with four articles, while the latter can only have one.

Although such a phenomenon may seem a bit silly, it can be regarded as an unspoken rule of the industry.

After all, postgraduates who work for their supervisors are postgraduates who want to publish articles. In the future, if they want to continue to do scientific research, go abroad to study for a doctorate or apply for a post-doctorate, SCI articles are also very important. Quality is also one of the main indicators for assessing its scientific research capabilities.

Before, Xu Qiu's PCE11 system was actually a similar operation. He is not a saint. When he has no ability to change the rules, it is a good choice to temporarily integrate into the rules.

Wei Xingsi put down his teacup, and didn't rush to announce "the group meeting is over", but looked at his students, intending to find a "target".

Wu Feifei's review is at the end, and it will be submitted in a few days, because it is the editor of the new Adv.

Not to mention Xu Qiu, Han Jiaying, and Chen Wanqing, they have made a breakthrough in the field of non-fullerenes. From the current point of view, let’s not talk about the manpower;

Even for Duan Yun and Tian Qing, it is safe to post an article for the weaker district 1/2 respectively.

After all the calculations, only Sun Wo has no articles.

But Sun Wo is only an undergraduate student, and he will only come here to study for a master's degree, not a doctorate, so he can't push too hard.

After looking around, Wei Xingsi found that he couldn't find the target of PUSH...