Siheyuan: Starting from a Truck Driver

"Yes..." Ran Qiuye hurriedly searched for a pen and paper in her canvas bag, but when she touched the paper, she was stunned.

What's right? I'm a math teacher!

It didn't take Li Weidong long to master the knowledge needed to make solar cells. His physics skills were good enough to qualify him for Hu Guangliang's position.

He stretched himself, looked at Ran Qiuye who was still copying books, and said, "Teacher Ran, we are about to close, we should go back."

"Uh-huh."

Ran Qiuye put down his aching hands, looked at the thick notebook, and felt sad.

What did she do this morning?

"Goodbye, Teacher Ran."

Li Weidong, who was eager to go home and cook, said hello and was about to turn around and leave on his bicycle when he suddenly saw Ran Qiuye squatting on the ground.

"what happened?"

"The chain fell off."

Li Weidong quickly tied up his bicycle and said enthusiastically, "Let me try."

Then, sweat began to appear on Ran Qiuye's forehead.

In order to avoid getting her new clothes dirty, she had to find a wooden stick to try to lift the bicycle chain, but she failed several times.

For an experienced driver who often repairs bicycles, repairing a bicycle is as easy as cutting melons and vegetables.

Li Weidong took the wooden stick and easily lifted it up, and the chain reached the gear.

"Come on, try again."

Ran Qiuye obediently got on the bike, and Li Weidong slowly gave instructions beside him.

"kick"

"Can't move."

“Put some effort”

"It's no use trying hard."

“Push harder”

"Click."

The bicycle chain broke into two sections and lay limply on the dusty ground.

Ran Qiuye:

Li Weidong:

He never expected that this little girl, despite her quiet appearance, was actually quite strong.

There is no place to repair bicycles nearby, and the nearest one is three or four miles away.

Li Weidong felt a little guilty for letting a little girl go so far.

Fortunately, as an experienced driver, he always remembers to carry a rope with him.

He untied the rope on the back seat of the bicycle, tied one end to his own bicycle, and the other end to the front handlebar of Ran Qiuye's bicycle.

"Are you ready? I'm going to start pedaling."

"Okay, slow down."

Li Weidong pushed the pedal and the bicycle started slowly. Under the tension of the rope, Ran Qiuye sat on the bicycle and just had to hold the handlebars firmly.

The owner of the repair shop is surnamed Liu. Even in the cold winter, he still wears a thin tan coat and a pair of yellow clay shoes. Even in the shop, he always wears that tattered straw hat, and he doesn't seem to worry about affecting his image.

Although he had a peculiar personality, he had great skills and charged fair prices, only charging five cents to repair a chain.

"It's all thanks to you today, otherwise I don't know what to do."

"This is my responsibility, as it should be. You're welcome."

In the process of repairing the chain, Li Weidong's hands were inevitably stained with oil. When Ran Qiuye saw it, he took out a handkerchief from his pocket and handed it to him.

"Clean."

"How can this be so embarrassing..."

Before Ran Qiuye finished her words, she had already ridden away on her bicycle. Li Weidong watched her back disappear into the crowd, then put the handkerchief back into his pocket.

"Comrade, boss, do you have any soap?"

A tree-lined path outside a ministry compound in Beijing.

Hu Guangliang looked at the desolate scene around him and felt a little uneasy. He tightened his collar and walked quickly behind a tall figure.

"Weidong, why did you choose to meet here?"

"Don't you think it's a bad atmosphere?"

Li Weidong turned around and looked around, saying in a low voice: "Withered flowers, rotten leaves, withered branches, and the chilly wind are a perfect match."

"..." Hu Guangliang swallowed his saliva and asked cautiously: "Didn't you say that you need to prepare solar panels?"

Li Weidong took out a piece of paper from his pocket and handed it to him: "Copper sheet, ferric chloride solution, alcohol, tinning, multimeter, double-layer capacitor and toothpaste. I need these things, you estimate the price first!"

His expression was serious and his tone was heavy.

With one hand in his pocket, his hair messy and the wind blowing, and dust flying in the air, he looked like a villain from a TV show.

"Hey, man, have you been watching too many science fiction movies lately?"

"You saw through it."

In this era, which man doesn't want to catch a spy?

Hu Guangliang looked at the note and shook his head: "There is no problem with the above materials. I can just help you get a letter of introduction. But toothpaste? Do you think this will work?"

He didn't know much about the specific production methods of solar panels, but he knew that toothpaste was used to clean teeth. How could it be used to make equipment?

Li Weidong asked back: "Tell me, what are the main ingredients of toothpaste?"

Hu Guangliang's eyes lit up: "Calcium carbonate, calcium hydrogen phosphate, silicon dioxide, aluminum hydroxide...silicon dioxide!"

He opened his eyes wide with excitement, paced on the fallen leaves, and muttered to himself: "Silicon dioxide is polycrystalline silicon, which can produce photovoltaic effect. When light shines on the surface of silicon dioxide, some photons will be absorbed by the silicon material; the energy of the photons is transferred to the silicon atoms, causing electron transitions and forming a potential difference on both sides of the PN junction. When the external circuit is connected, this voltage will drive the current to pass through and generate a certain output power."

"Great! It's just great! Compared to the single-crystal silicon solar cells from Bell Labs, the cost of silicon dioxide is much lower."

Li Weidong nodded. "Not only that, if you etch nanometer-scale holes in the silicon dioxide sheet and then use a silicon dioxide photonic crystal coating, you can greatly improve the efficiency of photoelectric conversion. I have calculated that the conversion efficiency of solar panels made using this technology can reach 80%."

"80%!" Hu Guangliang's eyes suddenly widened.

As a university graduate who is committed to scientific research, he did not give up learning cutting-edge technology while working in the ministry. In the ministry, he had the opportunity to access foreign academic journals. Bell Labs was hailed as a miracle of innovative energy, but the conversion efficiency of its solar panels was less than 30%.

The higher the efficiency, the more electricity a solar panel of the same area can generate. Hu Guangliang originally thought that Li Weidong was just having a sudden idea, but now he realizes that solar cells may have great potential.

Working in the ministry, Hu Guangliang has a deeper understanding of the domestic energy situation. Most of the domestic power generation equipment relies on imports, the quantity is small and failures are frequent. The national power supply is tight, even the capital often has power outages, not to mention the countryside, most areas have not yet been electrified.

In terms of industrial production, the first consideration when planning factories is power supply. Although Li Weidong's solar panels are limited by sunlight and cannot provide continuous power, they are sufficient for ordinary families. If they can be successfully developed, it will undoubtedly be a great thing for the country and the people.

Thinking of this, Hu Guangliang immediately returned to the ministry and assisted Li Weidong in issuing the introduction letter required for purchasing materials. These materials are common chemical products, non-hazardous, and fully in line with regulations.

The total cost was 1.2 yuan, and the most expensive item was the double-layer capacitor. Yu Li held the capacitor and asked curiously, "Brother Weidong, what is this round thing? It looks bigger than the semiconductor in the radio?"

"Similar to semiconductors, used to stabilize voltage."

Li Weidong placed the copper sheet cut into a rectangular shape on the table and carefully outlined the circuit line on the copper sheet with ferric chloride solution. After the lines dried, he asked Yu Li to help clean the copper sheet with alcohol. Although she didn't believe that a piece of copper could generate electricity, she was happy to help.

After cleaning, Li Weidong plated a layer of tin on the circuit line, then applied a layer of toothpaste, and finally soldered the positive and negative poles of the copper sheet to the two wires.

"It should be about done. Let's go to the yard and test it."

Li Weidong walked out of the door with the copper coin and lamp holder.

It was just after lunch and the sun was shining brightly. The residents in the courtyard moved out their chairs to enjoy the warmth outdoors.

The adults were chatting about family matters, and the children were chasing and playing around. The lively scene was full of life. Suddenly, a copper plate and a lamp holder attracted everyone's attention.

He Yu came over with his daughter Mei in his arms and asked Li Weidong, "Brother Weidong, what are you doing?" Li Weidong turned around and saw that it was He Yu. He joked with Mei first, and then replied, "I am making solar panels."

"What is that? What is a solar panel?" He Yu looked confused.

Of course he knew about solar panels, they were big golden cakes hanging in the sky. He had also seen batteries, he sold No. 2 flashlight batteries at the supply and marketing cooperative for 1.15 yuan with an industrial coupon. But putting these two things together really confused him.

Li Weidong was holding a solar panel in his hand. While showing it, he said to him: "This thing can receive solar energy and convert the sun's radiation energy into electrical energy." He Yu immediately wanted to question it. The solar panel sounded like a fairy tale and it was simply not real.

"Don't be ridiculous. This is just a copper coin. Can the sun be turned into electricity? Uncle Liu's son got an electric shock by accident last year. If it wasn't for our Third Uncle rushing him to the hospital, he would have died." He Yu retorted.

"Okay, okay, I know you are right about this." Li Weidong knew that if someone was discussing whether rocket fuel was coal or washed coal, then he should stop arguing.

When Li Weidong was talking to He Yu, many people in the yard were attracted by the noise. They were very interested in Li Weidong's new gadgets. In the whole yard, Li Weidong was the one who loved to tinker with things the most. Last time it was a washing machine, but this time it was unknown what he was tinkering with.

A passerby asked casually, and Li Weidong answered patiently, repeating what he had said. This made others more interested. They didn't care whether the solar panels could generate electricity, but only cared about what benefits they could get from it.

Yan Bugui, a primary school teacher in the front yard, also came over. He was a knowledgeable man. Although he was only a primary school teacher, he knew a little more than his neighbors who had not received higher education. He had heard of solar panels but had never seen one. The key point was that the power outages at home were frequent, which was very annoying. When Yan Bugui heard Li Weidong talk about solar panels, he felt that this was an opportunity to get rich.