Toyobo to Practicalize Power-Generating Material for Organic Photovoltaics With World’s Top-Level Conversion Efficiency Under Room Light

PVTIME - Toyobo Co., Ltd.
and the French government
research institute CEA have
succeeded in making trial
organic photovoltaics (OPV) small cells
on a glass substrate with the
world’s top-level
conversion efficiency*1 in a dim
room, and trial OPV modules on a lightweight and thin
PET (polyethylene terephthalate) film substrate during their
joint research project. The trial products
use a power-generating
material for

OPV that Toyobo has been developing. OPV has attracted wide attention as a next-generation solar cell. Toyobo aims to put
the material into early
practical use, mainly as a
wireless power source in such devices as temperature-humidity and motion sensors.

OPV cell is a solar cell which
can be created by coating organic power-generating materials including carbon
and sulfur atoms on a glass or plastic substrate with electrodes. As it can be
shaped into flexible and thin forms, it affixes easily to walls or cloth
surfaces where prevalent inorganic solar cells are unsuitable for installing.
There are thus high expectations for OPV as a wireless power source for sensors
and wearable devices, which are indispensable for the Internet of Things (IoT.)

Toyobo has been developing a
power-generating material for OPV to yield high power outputs from
low-illumination room light sources by utilizing organic synthesis technologies
the company has cultivated in its years of research on fine chemicals*2. The material can dissolve easily even in
halogen-free solvents, allowing it to be coated evenly on a substrate, thus it
can generate power stably with little individual difference.

To put the material into
practical use at an early date, Toyobo conducted the joint research with CEA
for six months from June last year. During the undertaking, Toyobo and CEA
succeeded in making the OPV small cells on a glass substrate with the world’s
top-level conversion efficiency by optimizing the solvents and coating
technique. In a verification experiment under neon lighting with 220 lux,
equivalent to the brightness of a dark room, the OPV module on PET film substrate Power-generating
material for OPV

trial product was confirmed to have attained a conversion efficiency of
about 25 percent, or 60 percent higher*3 than that of amorphous silicon solar cells commonly used for desktop
calculators. They also completed prototype OPV modules on a PET film substrate
with an effective area of 18 square centimeters although coating a
power-generating material on a PET film, which was more difficult than on a
glass substrate. The module was able to output about 130 microwatts under the
same illumination.

Toyobo plans to propose the use of this material mainly to solar cell
makers, based on the know-how acquired through the joint research. Firstly, the
company aims to have the material used by March 2023 mainly as a wireless power
source for temperature-humidity and motion sensors.

*1 According to Toyobo’s research as of March 23, 2020

*2 According to Toyobo’s press release dated July 31, 2019

*3 Compared with a conversion efficiency of 16 percent for general
amorphous silicon solar cells, as measured by Toyobo under a brightness of 220