I Have a Research Support System

On Saturday, the Simulation Lab presented results based on three transport layer optimization methods.

The first method, that is, spin-coating with several new transport layer materials that do not require high-temperature annealing.

The performance of devices prepared by this method is generally slightly lower than that obtained by the previous high-temperature zinc oxide method, and the device efficiency is scattered between 80-95% of the standard sample efficiency.

The decline in performance is not necessarily a problem with the material itself, but may also be due to insufficient exploration of the processing technology.

Not only that, most of these transport layer materials are based on positive structure devices, that is, the PEDOT system, Xu Qiu does not want to change the device structure rashly now.

After all, from the time Chen Wanqing joined the team to the present, he has been using the zinc oxide-based inverted structure system for three years. If you want to switch systems, the time and cost required to re-adapt to the new conditions is very high.

This is also the choice of most research groups-usually it is not easy to replace the mature experimental conditions, unless the new conditions can greatly improve the performance, or have irreplaceable advantages in other aspects.

In fact, Xu Qiu also thought about whether to find someone in the research group to specialize in the research and development of positive structure devices.

But now everyone in the group has their own research areas to be responsible for, and there is a real shortage of manpower.

Moreover, it would not be good if the work was forcibly assigned, because it was different from the nature of Xu Qiu asking others to do experiments for him before.

I helped him with experiments before, whether it was seniors, juniors, post-doctorate seniors, or Mo Wenlin and Tian Qing, they were all beneficial in the end, at least they could be used as second authors of articles, and some made great contributions It can even be a joint one.

The development of positive structure devices is a long-term investment experiment.

This kind of experiment does not see any benefits for individuals in a short period of time, but is only beneficial to the long-term development of the research group.

For example, when there is a problem with the inverted structure one day, if the group has the basis for developing positive structure devices, there will be an additional way to solve the problem.

From Wei Xingsi's point of view, it is reasonable to ask a certain student to do this, and the student has no choice.

But Xu Qiu is still a student after all, and he is more inclined to the student group from his standpoint.

Most importantly, he didn't want to be this villain either.

In Xu Qiu's view, if you want others to work, you have to let them see the rewards.

They are all adults, so if you can lure them, you can lure them.

For painting cakes and so on, others may help you sincerely the first time, reluctantly help you the second time, and not necessarily the third or fourth time after that.

Therefore, Xu Qiu finally decided to temporarily classify this method as an option, which is Plan B.

The second method is to use the original sol-gel method to prepare zinc oxide thin films, while reducing the annealing temperature.

The results show that the annealing temperature of 150 degrees Celsius is just a critical point. At this time, the efficiency of the standard device can reach 95%-100%, that is, the performance of the device at the annealing temperature of 200 degrees Celsius is not large.

When the annealing temperature of the ZnO transport layer was lowered to 120 degrees Celsius, the performance of the device declined significantly, only 75-85% of the standard conditions.

That is to say, if you choose the second method, the annealing condition of at least 150 degrees Celsius is required.

Whether such temperature annealing has any effect on the laminated device needs further research.

The third method is the method of Yang Yang's research group. They call the zinc oxide obtained by the low temperature method α-ZnO, which is alpha-zinc oxide.

The device performance of using α-ZnO as the transport layer can reach 85-100% of the standard device efficiency, and some optimization may be needed, but it is generally acceptable.

Because it happens to be an inverted structure and does not conflict with the current processing technology, even if it needs to be optimized, it will not be too difficult.

Xu Qiu finally decided to test the waters with the second and third methods at the same time. There is a high probability that the first method will not be used unless a new situation arises again.

At this time, in the dormitory, Sun Yifan was doing a live broadcast.

Today is Saturday, and Sun Yifan usually broadcasts live for the whole day. From Sunday to Friday, he usually broadcasts for three hours. Therefore, he usually downloads the broadcast before Xu Qiu returns from the laboratory.

Seeing Xu Qiu walking towards him, Sun Yifan turned off the microphone of the live broadcast, and asked, By the way, the class group said that they will organize an autumn outing, and the time is set for next Saturday. Are you going?

I'm not going, I don't have time. Xu Qiu said succinctly. Mu Xue, the monitor of the doctoral class, even asked him privately if he wanted to go, but he directly refused. Once he entered the scientific research, the class activities were just passers-by.

After a pause, Xu Qiu asked back, Are you going?

I'm not going either, Sun Yifan shook his head, and said, I heard that not many people responded to the call for this autumn outing. There are less than 30 doctoral students, majors, and masters in total, and the main force is still masters. , after all, they have no scientific research pressure.

After finishing speaking, Sun Yifan pointed to the computer in front of him, and continued: I kind of wanted to go, but I have to make up time for the live broadcast on Saturday, so I really can't leave.

Xu Qiu glanced at Sun Yifan's computer screen. The number of real-time viewers in the live broadcast room is now 69 people, and there is a flame-shaped index, which should be the popularity of the live broadcast room. There are 1.7W. There are not many bullet screens, only a few in a minute .

Xu Qiu asked curiously: How is your live broadcast now? Do you earn a lot of money from live broadcasting?

That's it. It's been broadcast for more than a week, and I've earned almost a hundred yuan, so I'll treat it as a hobby. Sun Yifan said casually.

It should be necessary to accumulate fans. Xu Qiu thought for a while and said, Probably a long-term project?

Well, you're right. People have inertia. They're used to watching an anchor, and they'll keep watching. Sun Yifan changed the subject:

However, this is only theoretical. Now that the major capitals in the live broadcasting industry are rushing in, it is hard to say what will happen in the end. Whether the Dousha platform can survive this battle is unknown.

That's true. Xu Qiu nodded, and then asked, Seeing how hard you work, do you have any guaranteed monthly income?

Well... Yes, I just signed a contract. As long as I broadcast enough time next month, I can get more than 2,000 yuan as a guarantee. Sun Yifan paused, and said: Now the platform has activities to attract newcomers, and newcomers sign contracts. Afterwards, there will be a commission to get, Xu Qiu, you come and try it, and we will pay seven or three times when we get the commission.

You are seven and I am seven? Xu Qiu asked with a smile.

It's still a question, of course you are seven. Sun Yifan said in an affirmative tone.

Then how much is the commission? Xu Qiu asked.

One month's salary after signing the contract. Sun Yifan replied.

Two thousand yuan? That's still disturbing. Xu Qiu spread his hands.

I knew you would never come if you were busy. Sun Yifan laughed.

Xu Qiu feels that this way of pulling people's heads is familiar. In the early days of food delivery software, there were various subsidies on the platform, and a meal was often only a penny. Later, several food delivery app giants cultivated user habits and took part in the competition After several small companies squeezed out, the price gradually increased.

To put it bluntly, it is essentially a simple price war. Although the moves are simple, they are easy to use.

The live broadcast industry has just started now, and the subsidy is sure to be strong, but it is estimated that cutting leeks will be inevitable in the future. After all, capital investment in the live broadcast industry is definitely not to enrich the spiritual world of the flower growers, nor is it for charity. It is for asset growth.

The main body must be cutting the leeks of the audience, but the converse is not necessarily cutting the anchors, just like the commissions charged by food delivery platforms to merchants are getting higher and higher, Xu Qiu will not go into this muddy water.

Sunday afternoon, material one 216.

Xu Qiu began to write an article on the work of full solution, colorful, and translucent that the senior sister was in charge of, and at the same time planned the synthesis route of PTQ series donors and Y series acceptors next week.

Mo Wenlin plans to vapor-deposit two batches of devices, one normal and one translucent, and then use the four-terminal method to test the effects of more than ten systems of laminated devices given by Xu Qiu.

In the evening, they got the device results.

The final result is not satisfactory. After the four-terminal stacking method, the performance of the stacked system with the highest efficiency remains the same, similar to 10%+10%=10%, two systems with an efficiency of 10%. , the device efficiency after series stacking is still only 10%.

Even many systems have the phenomenon of 10%+10%\u003c10%, that is, two 10% devices are stacked, and the final device efficiency is only 9%, 8%, and 7%.

In this situation, Xu Qiu couldn't help thinking of the dreamy pet metamorphosis.

The initial attempt failed, and Xu Qiu began to analyze the reasons based on the experimental data.

First of all, because the four-terminal method does not have the problem of device processing technology, the main problem is the current matching problem.

The laminated system has very high requirements on the two systems of the front and rear batteries. As long as the deviation is slightly larger, for example, the deviation exceeds 20%, the performance of the final device will decline significantly.

In addition, Xu Qiu also found a problem.

That is, even if the top cell uses a 15-nanometer thin-layer gold-silver electrode, the light absorption loss caused by the translucent top cell is still very large.

In other words, very little light is left for the bottom cell, making it difficult to make the current density of the bottom cell high.

Xu Qiu deliberately tested the average visible light transmittance (AVT) of a single gold and silver electrode before, and it was only 60%-70%, which means that this electrode alone will lose 30%-40% of light.

If it is placed in a translucent device, it doesn't matter, because what is lost is the light reflected twice, which accounts for a small proportion and has little impact on efficiency.

But now to make stacked devices, this is particularly critical, which is equivalent to taking away the ration (light) of the bottom battery.

Thinking of this, Xu Qiu suddenly realized something.

He resolutely looked through the device structures of other people in the literature, and found that the thin-layer electrodes used by others in the two-terminal method, silver will be evaporated very thin, usually only 2-5 nanometers.

If this is the case, it can explain why other colleagues do not use the four-terminal method to prepare organic photovoltaic stacked devices.

Without it, performance is poor.