Scientists at China’s national Chiao Tung and Tsing Hua universities have developed a PV module based on organic solar cells they claim offers the highest efficiency reported for a panel of its kind which has an active area of more than 100cm2.
Presented in the paper Large area organic photovoltaic modules fabricated on a 30cm by 20cm substrate with a power conversion efficiency of 9.5% – published in Solar Energy Materials and Solar Cells, the device was manufactured with a non-fullerene based active layer and interlayers deposited by blade coating on a 30x20cm glass substrate.
The NF3000‐P and NF3000‐N polymers commonly used in organic solar cell production were used in the device as polymer donor and small‐molecular acceptor, respectively. The researchers used the NF3000 solution developed by Taiwanese semiconductor manufacturer Raynergy Tek Incorporation for the development of a bulk heterojunction (BHJ) layer.
“All of the NF3000 BHJ films were fabricated using a blend solution prepared by mixing the NF3000-P (10mg/ml) with NF3000-N (10mg/ml) in 1ml of chlorobenzene and with the addition of 0.5% weight of 1,8-diiodooctane,” said the China group. The solution was stirred at 100 degrees Celsius in a nitrogen-filled glove box overnight and then cooled to room temperature before coating.
The bulk heterojunction films are said to have an absorption band of 300-850nm, making the panel suitable for indoor lighting as well.
The module, with an active area of 216cm2, was manufactured in the nitrogen box and encapsulated by glass. It has reportedly demonstrated efficiency of 9.5% with parameters including open-circuit voltage, short-circuit current density and fill factor almost unchanged during light soaking under 10,000 lux white LED irradiation. “The conversion efficiency can still maintain about 92.5% of the initial value after 610 hours of light exposure, indicating its superior air stability,” the scientists stated.
The researchers said the module had exhibited open circuit voltage of 10.6 V, a short circuit current of 1.82mA and a fill factor of 43.3% – enough to operate most low-power-consumption electronic devices.
Source: pv magazine