Solar cells that can fully generate electricity under indoor light

In order to realize a "paste type sensor" that can generate electricity efficiently in a dimly lit room and cost only 1,000 yen, development of a flexible solar cell is underway. A thin film solar cell manufactured using an organic semiconductor capable of reducing cost will be made into a microfiber of a size of 10 (m-9 m) and woven into a "cloth". It is planned to use this solar cell for plant factories. Megumi, Director of the Okayama Research Center of the Green Sensor Network Research Institute of NMEMS Technology Research Institute, Japan, gave a speech on the development of nanofiber independent power supply in sensor network system, and introduced the development details of this solar cell.

The goal of the solar cell currently under development is to provide a self-contained power supply that does not need to be replaced after installation, and does not need to be replaced. As a power source for the sensor network terminal, an existing button type battery can also be used, but it must be replaced after the service life is reached.

Gaya is developing solar cells that can fully generate electricity even under indoor light. According to reports, the general indoor illumination is 1000lux in front of the window, 400lux on the table, and 100lux under the table. The goal of Tanioka is to develop a solar cell that can drive the sensor network terminal as long as it reaches the illumination of 400lux on the table.

Suitable for the characteristics of the sensor network terminal use environment

In order to make solar cells suitable for the characteristics of a band-aid sensor network terminal, Gaya uses polymer materials in organic semiconductors.

A solar cell using an organic semiconductor is characterized in that a resin substrate is used instead of a silicon substrate, so that the solar cell can be made light, thin, and soft. If you can stick to an object, you can achieve a free layout. Moreover, even if an external force is applied during installation and after installation, it is not easily damaged. This solar cell is not only thin in thickness, but also simplifies the mounting jig, so it does not occupy a place for installation.

The use of organic semiconductors also tends to reduce mass production costs. Since it is not necessary to use expensive and bulky vacuum manufacturing equipment, it is only necessary to coat the polymer material under air conditions and form a thin film semiconductor. Moreover, reliability and longevity can also fully meet the demand. Because it can be equipped with a power storage function, it can supply power stably in an environment where the required illumination is not achieved.

The power generation efficiency of solar cells using organic semiconductors has reached the level of amorphous (polycrystalline) silicon solar cells that are not inferior to those used in residential and industrial applications. Among the currently disclosed products, the highest level of efficiency of organic semiconductor solar cells is 12%. Under indoor illumination conditions of less than 1000lux, the efficiency is higher than that of amorphous silicon solar cells. In an indoor environment, organic thin film solar cells are also very advantageous in terms of efficiency.

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