Visualization 1 indicates the working process of the audio transmission system.
To further demonstrate the optical communication properties of the samples, the perovskite film was introduced to an audio signal transmission system with ultraviolet LED as the source and a Si photodiode (BPW21R) as the receiver end. The audio signal from the computer is sent to a bias amplifier to modulate its bias voltage. Then, it was used to drive the ultraviolet LED with a current buffer; with the help of color conversion material, the ultraviolet light will be transformed into modulated green light. With a Si-based LED, the modulated optical signal will be transformed into a current single again. After a power amplifier, the single will be sent to the speaker.
As can be seen, the signal can be received while the film exists. Moreover, without the film, no sound will be heard. Besides, the sharp and water conditions do not influence the signal highly, so it still works in curved and watery conditions.