Recent research has signaled out wide bandgap perovskites for their potential as a solar cell material for high efficiency light-receiving devices. Optical wireless power transmission (OWPT) is just one promising application of devices such as these.

Ishikawa et al. studied the potential of widegap bromide-based perovskite thin films for optical wireless power transmission systems. They compared and characterized wide-bandgap CH3NH3PbBr3 (MAPbBr3) thin films on glass and TiO2.

An OWPT system capable of feeding a long distance and a large amount of power requires the use of short wavelength light, such as blue LEDs, in order to improve the efficiency of the light-receiving device.

“A widegap perovskite solar cell can realize an inexpensive, highly efficient, lightweight and flexible light-receiving device, and because the band gap of a perovskite solar cell can be continuously modulated, it can be customized according to the wavelength of the light source,” said author Ryousuke Ishikawa.

The authors observed a diffusion length of 1 µm in the widegap perovskite thin film of the device and found that the optical properties changed depending on the structure of either glass or TiO2 thin films. The solar cells demonstrated 20.2% efficiency under blue LEDs, indicating high optical quality sufficient for potential wireless power transmission.

“The next steps are to improve conversion efficiency by making multi-junction perovskite solar cells with the same band gap,” said Ishikawa. “To achieve this, we hope to develop a process to fabricate another perovskite solar cell on top of the wide bandgap solar cell, or to transfer and stack perovskite solar cells separately prepared.”

Source: “Widegap CH3NH3PbBr3 solar cells for optical wireless power transmission application,” by Ryousuke Ishikawa, Takuya Kato, Ryotaro Anzo, Momoko Nagatake, Tatsuya Nishimura, Nozomu Tsuboi, and Shinsuke Miyajima, Applied Physics Letters (2020). The article can be accessed at https://doi.org/10.1063/5.0010009.