Introduction

This time, we will explain about "perovskite solar cells."
There is currently a technology that is poised to dramatically change the future of energy.
This is the "perovskite solar cell."
According to the " Next Generation Solar Cell Strategy " announced by the Ministry of Economy, Trade and Industry in November 2024, the goal is to introduce 20GW (equivalent to the power of 20 nuclear power plants) of perovskite solar cells by 2040.

The background to this is a sense of crisis over the current situation in which China holds the lead in solar power generation, and Japan's geopolitical advantage as a major producer of iodine.
In this article, we will explain the innovations brought about by perovskite technology, which is attracting attention against this background, and its position in national strategy.

What are perovskite solar cells?

Perovskite solar cells are solar cells that use a material with a crystal structure called perovskite as the light absorption layer.The notable features are as follows:

High efficiency

According to the latest report published by the National Institute of Advanced Industrial Science and Technology, a conversion efficiency of 26.7%, close to the theoretical limit, has been demonstrated for a single-junction type, and a conversion efficiency of 28.7% for a multi-junction type.
" Kyoto University and others realize tandem all-perovskite PV "

Low cost

By using printing technology (spin coating method), it is said that it can be manufactured at a lower temperature and in a shorter time than silicon solar cells.

Flexibility and light weight

It is less than 1μm thick and has the flexibility of a film, allowing for dramatically increased freedom in where it can be installed, such as on glass, exterior walls, clothing, etc.

Japan's Geopolitical Advantage and Energy Security

Japan is the world's second largest producer of iodine, one of the main raw materials for perovskite solar cells, accounting for approximately 30% of global production.
Among these, iodine derived from the brine of gas fields in Chiba Prefecture is an important resource, accounting for approximately 80% of domestic production.

China accounts for the majority of the world's production of high-purity silicon, the raw material for silicon solar cells, and supply risks have always been a concern. This risk is a concern not only for Japan, but also for countries around the world.
In contrast, some of the main raw materials for perovskite solar cells can be steadily procured within Japan, marking a major step towards local production and consumption of energy.

In addition, because it is possible to repurpose existing chemical plant equipment, this would enable production to continue even in the unlikely event that international supply networks are cut off, which is thought to be of great significance in terms of energy security.

Domestic supply chains and job creation

The widespread use of perovskite solar cells is expected to bring not just technological innovation, but also the creation of a self-contained supply chain in Japan and new employment opportunities.

Many of the materials required for manufacturing can be procured domestically, and furthermore, equipment from existing chemical plants and electronic component factories can be repurposed, so the country has an established infrastructure for the equipment industry.

According to the " Next-Generation Solar Cell Strategy " published by the Ministry of Economy, Trade and Industry in November 2024, if mass production of perovskite solar cells gets fully underway, employment is expected in the following fields by 2030.

• Chemical industry: over 30,000 people
• Construction industry and installation work: more than 40,000 people
• Conservation and management business: less than 20,000 people

Movements to create jobs are also underway in regional areas. For example, in the Tohoku region, efforts are underway to set up training centers for power generation equipment construction engineers.

The potential of tandem solar cells

Perovskite solar cells are highly efficient even on their own, but their conversion efficiency can be further increased by stacking them with silicon solar cells in a "tandem" configuration.
In this case, the theoretical limit is said to be a maximum of 43% (source: PR TIMES (Toshiba Infrastructure Systems) ), and if practical application progresses, it could rewrite the conventional wisdom about solar cells.

Examples of initiatives by domestic companies

Domestic companies are also starting to take action. According to an official release from Sekisui Chemical , the company aims to establish a mass production system with a capacity of 100 MW/year by 2027.
Toshiba has also recorded an efficiency of over 31% in its tandem solar cells during demonstration, and is currently working on development toward commercialization.

summary

Perovskite solar cells have multiple advantages, such as being lightweight, flexible, highly efficient, and low cost, and are a rare energy technology in which Japan can take a lead in everything from raw material procurement to manufacturing and installation.

Learning from the lessons of its loss of semiconductor leadership, Japan needs to strategically promote the use of semiconductors, based on domestic production and intellectual property protection. The government's target of introducing 20GW by 2040 is only the first step.

Perovskite solar cells are not just a technological innovation; they also represent an opportunity for a "Reiwa Industrial Revolution" that will support Japan's energy security and industrial revival.