Mr. Hirohisa Iwabayashi and Dr. Ryohei Mori at Green Science Alliance Co., Ltd. have developed a dry type quantum dot solar cell with printing procedure.

Mr. Hirohisa Iwabayashi and Dr. Ryohei Mori at Green Science Alliance Co., Ltd. have developed a dry type quantum dot solar cell with printing procedure.

Environmental problems such as the climate crisis, depletion of natural resources, extinction of species etc. caused by human population explosion and activity is becoming a serious issue. Creating a society which is independent from petroleum and fossil fuel is an urgent task. Solar power is one of the ideal forms of renewable energy because light energy from the sun is almost unlimited, and it can be considered clean energy.

Solar cells can be largely classified into a most widely used silicon base, chemical compound base, organic base and perovskite solar cell. Some of them are still at the experimental stage, although quantum dot solar cell has a theoretical conversion efficiency as high as 75%, which is more than twice that of silicon based solar cell. Thus, quantum dot solar cell is regarded as to be the next generation solar cell.

Quantum dots are nanoscale particles possessing unique optical properties, according to the law of quantum chemistry and quantum mechanics. Normally, they have a diameter of 2 to 10 nm and consist of around several dozen to several thousand atoms or molecules. Because the size of the colloidal nanoscale particles can be used to adjust the band gap, the crystals have characteristic emission properties that depend on particle size. Quantum dots can be applied to solar cell, display, LED, sensor, bio-imaging, medical usage, etc.

Green Science Alliance has been developing various types of quantum dot, quantum dot composite materials, quantum dot inkjet inks etc. This time, they have applied their own materials for quantum dot solar cell for its electrode, electrolyte, with printing procedure. Light to electricity conversion efficiency is still as low as a little more than 1%. Still, they will keep challenging to enhance conversion efficiency by optimizing the kind of quantum dot, electrode, electrolyte materials, as well as by modifying printing procedure.

Green Science Alliance is the company which focuses on developing cutting edge materials and technologies for carbon free society. More precisely, they research nature biomass biodegradable resin, coating, paint, color, glue, fuel (nature biomass based chemical products), next generation solar cell, fuel cell, rechargeable battery, CO2 capture and utilization (artificial photosynthesis) etc. Some of their technologies are registered by the United Nation Organization (UNIDO's platform "STePP", WIPO GREEN) and they were also selected as finalists on the startup incubation programme of UNOPS GIC Japan in 2020.