A perovskite photo diode that becomes a viable LED when its bias is reversed has been created at Linköping University in Sweden, allowing bidirectional communication between two identical devices.

“We have managed to integrate optical signal transmission and reception into one circuit, something that makes it possible to transmit optical signals in both directions between two identical circuits,” said LiU professor Feng Gao.

The solution-processed diode has an external quantum efficiency of > 21% as an LED, and detects light on a sub-pW scale, and can work at tens of MHz in both modes, according to ‘Bidirectional optical signal transmission between two identical devices using perovskite diodes’, a paper published in Nature Electronics.

“Benefiting from the small Stokes shift of perovskites, our diodes exhibit a specific detectivity of >2×1012 Jones) at its ~804nm emission which allows an optical signal exchange between two identical diodes,” according to the paper.

The team used the proof-of-concept device to sense a human pulse and in a bi-directional optical comms system.

In 2018 2018, Chunxiong Bao from the team discovered identified a perovskite with good characteristics for a photodetector, which was published in Advanced Materials.

Last year Weidong Xu, also of the Linköping University team, developed a perovskite light-emitting diode with an efficiency of 21%, which was published in Nature Photonics.

Linköping Iniversity worked with Shenzhen University, Nanjing Tech University, Nanjing University of Aeronautics and Astronautics, and the Chinese University of Hong Kong