Organic PV module with 12.36% efficiency

Researchers from Zhejiang University in China have fabricated an organic solar module with a certified efficiency of 12.36%.

The panel was built by connecting seven solar cells in series with an efficiency of 16.71%. Laser-based P1, P2, and P3 scribes were used to connect the anode of a cell to the cathode of the subsequent cell. The cells were then placed on patterned indium tin oxide-coated glass substrates and were spin-coated with zinc oxide (ZnO) precursor solution at 200 C for an hour in the air.

The scientists developed the panel with a quaternary approach by using a commercially available polymer, PM6, and a fullerene electron acceptor known as PC71BM, which is commonly used in the most efficient organic photovoltaic devices. They also used two non-fullerene acceptors (NFAs) known as Y6 and ITIC, which have both been applied in previous research on organic PV.

“The PC71BM was added as the third component in the PM6:Y6 system to optimize the charge transport,” the academics said. “The ITIC was further added as the fourth component to maximize the photon harvesting.”

The addition of PC71BM and ITIC to the binary PM6:Y6 blend creates more donor/acceptor interfaces and favors exciton dissociation and charge transport, which results in an increased short-circuit current.

The module, which measures 19.34 cm2, with a geometrical filling factor of 95.5%, has a certified efficiency of 12.36%, an open-circuit voltage of 6.06 V, a short circuit current of 3.07 mA⋅cm−2, and a fill factor of 66.45%.

At an experimental level, the scientists were also able to increase the device's efficiency by 0.89% and achieved an open-circuit voltage of 6.024 V, a short circuit current of 3.11 mA⋅cm−2, and a fill factor of 70.7%. This efficiency is purportedly the highest value for an inverted large-area module to date.

“The excellent performance of photovoltaic devices and large-area modules proves the synergy of multiple components, paving a way to the commercial application of the high-performance photovoltaic cells,” the researchers concluded.

They described the module in “19.34 cm2 large-area quaternary organic photovoltaic module with 12.36% certified efficiency,” which was recently published in Photonics Research.