I Have a Research Support System

After the spin coating was completed, Xu Qiu approached Chen Wanqing and asked for advice on the next experiment.

The senior sister took out the experiment notebook, while writing and drawing, while explaining the teaching:

"What we finally want to get is a multi-layer solar cell device, such as the current system, the positive structure is Glass/ITO/PEDOT:PSS/P3HT:PC[60]BM:PC[70]BM/Ca/Al .

There are six layers in total, and the layers are separated by "/", and ":" means that the layer is blended with two or more substances.

So, the work you have done these days is:

First, clean the glass substrate with the ITO pattern to obtain the Glass/ITO part;

Then, spin-coat PEDOT:PSS solution and effective layer, obtain PEDOT:PSS/P3HT:PC[60]BM:PC[70]BM part;

The last step, which is to be done next, is to vapor-deposit calcium and aluminum on the substrate by vacuum coating method to obtain the Ca/Al part.

The principle of the vacuum coating method is to heat the target material under vacuum conditions to make it gasify, and the gaseous molecules formed by the target material will move in the chamber, and finally evenly deposit on the surface of the sample to form a thin film.

There are two heating methods we use, one is beam source furnace heating, and the other is tungsten wire heating.

The operation of evaporation is cumbersome, and there are many details that need to be paid attention to, so I will guide you personally. "

"Okay, senior sister." Xu Qiu said.

…………

The two took precautions and entered the laboratory.

Xu Qiu first took the spin-coated substrate out of the glove box, and then quickly transferred it to the glove box equipped with an evaporation device.

There are three rubber gloves attached to this glove box, and only one person can enter it at a time.

So, Xu Qiu entered the box, while the senior sister was outside.

There are mainly two large equipment in the box, and the left one is the evaporation device.

The cabin body of the evaporation cabin is made of thick steel plates, and the hatch door is connected to the cabin body with rails.

Xu Qiu pushed the cabin door to the right, and it was quite heavy.

He curiously said: "Senior sister, this equipment is not cheap."

"The whole set of equipment is about 200,000 yuan, including the evaporation chamber, molecular pump, circulating water system, and main console. It was ordered by a company in Shenyang that specializes in vacuum equipment.

Their company is far away from here, so if it breaks, it will be troublesome to repair. Last time the circulating water broke down, they came to repair it, and the toll cost 5,000. "Chen Wanqing.

"How does senior sister know so clearly?" Xu Qiu asked doubtfully.

"Because the school needs to count the fixed assets of the laboratory, and those whose price exceeds 1,000 yuan must be reported. Although the laboratory is managed by Mr. Wei, the ownership belongs to the state, because the research funding applied for is provided by the state. Unless the boss himself It’s another matter if it’s out of pocket or the company pays.” Chen Wanqing said.

Xu Qiu nodded and began to look inside the cabin.

There are four cylindrical furnaces below, which should be beam source furnaces.

There are two metal platforms next to the four beam source furnaces. Each platform has a metal plate on it, about six centimeters long, three centimeters wide, and one centimeter thick. The metal plate is connected to the platform with hexagonal screws, and there is a certain gap in the middle.

"Sister, what is this for?" Xu Qiu asked, pointing to the platform.

"This is an electric current heating device. Put a basket made of tungsten wire between two platforms, press the two ends of the tungsten basket with a metal plate, and heat the tungsten basket with current, which can reach a very high temperature and make the inside of the basket The target material is vaporized and evaporated." Chen Wanqing said.

Xu Qiu continued to look at the cabin, and there was a probe-shaped object in the middle, hanging above the source beam furnace and the platform like a chandelier.

The senior sister followed Xu Qiu's gaze and introduced herself:

"This is a crystal oscillator device. A crystal oscillator plate is installed at the probe to detect the thickness of the evaporated film in real time. Its position must not be disturbed, because the current parameters have been calibrated. If its position is moved, the film will be damaged. Thick test results are not standard. In addition, the crystal oscillator has a lifespan, so it is necessary to replace the crystal oscillator regularly and re-calibrate the thickness.”

On the top of the cabin is a large circular metal baffle and a rotatable sample stage.

"The one above must be a sample stage, why is there a metal baffle installed below?" Xu Qiu asked.

"This metal baffle is called the sample baffle. When it is in the open state, it can effectively block the deposition of gas molecules on the surface of the sample. Therefore, we can use it to control the start and end time of evaporation and obtain precise thickness." Chen Wanqing said.

After understanding the situation inside the cabin, Xu Qiu began to make preparations before the evaporation.

The device structures of the two batches of substrates are different, and evaporation needs to be carried out twice.

The first batches were normal structures, that is, evaporated calcium and aluminum.

Xu Qiu first filled the tungsten basket with aluminum ingots of 99.995% purity, and then asked his senior sister to help open the baffle of the calcium beam source furnace.

The switch of the baffle is numerically controlled and needs to be operated from the main console outside the glove box.

After opening the baffle, he took out the ceramic crucible inside the beam source furnace, poured out the remaining residue after the last use, and then added two spoonfuls of new 99.995% pure calcium powder.

The ceramic crucible is special, can withstand high temperature of at least 1000 degrees Celsius, and is very stable, and will not react with the target material to generate impurities.

After finishing, he asked his senior to close the baffle of the beam source furnace.

Finally, he places the substrates face down on the sample holder and places the sample holder back on the sample stage.

"Sister, there's no problem, can you close the hatch?" Xu Qiu looked at Chen Wanqing.

"Yeah." Chen Wanqing nodded.

Xu Qiu pushed the hatch back to its original position from right to left, and then turned the two knobs on the top and bottom of the hatch until they couldn't be turned.

...

Xu Qiu left the glove box and came to the main console with her senior sister, because the rest of the operations were mainly done at the main console.

The master console is close to two meters high and is composed of more than a dozen modules, with a total of more than 30 control buttons.

"There are operating instructions next to it, just follow the instructions strictly." Chen Wanqing said.

Xu Qiu picked up the "Instructions for Vacuum Coating Apparatus" and looked through it. There were only two pages of A4 paper, not as many as imagined.

On the surface, he was reading the manual, but he was actually checking the system in his heart.

The system has copied the skills of the senior sister, and you can see the details of each operation, so the text version of the manual is not very meaningful.

"I've finished watching." Xu Qiu said.

"So fast?" Chen Wanqing said: "Okay, then you can operate it, and I will remind you if there is any problem."

The first step is to turn on the circulating water system and the air pump.

The former is used to cool the molecular pump, while the latter is used to push the sample baffle.

Xu Qiu found the circulating water device behind the main console, pressed the green start button, and heard the buzzing sound of the instrument, and the sound of water flowing if he listened carefully.

Then he walked over to the air pump.

There is an orange-red bottle cap-sized switch on the air pump that needs to be pulled up to start the machine.

Xu Qiu tried to pull it up, but the switch didn't move at all. He didn't dare to use too much force, so he said:

"Sister, how do you do it?"

"Fuck it hard."

"boom!"