Bidirectional photocurrent in all-perovskite multilayer junctions for modulable light detection

Wavelength-induced photocurrent polarity switching could be a new building block for various optical applications, such as visible light communication and color discrimination imaging. Organic–inorganic hybrid perovskites are versatile and easy to process, making them highly attractive for customized optoelectronic devices. Herein, a self-powered bidirectional photocurrent perovskite photodetector (BPPD) has been developed based on a vertical three-dimensional (3D)/quasi-two-dimensional (Q-2D)/3D perovskite multilayer junction. This BPPD shows positive photocurrent under short-wavelength light (300–524 nm) and negative photocurrent under long-wavelength light (524–800 nm), thereby delivering modulable photoresponse under multiple-light-beam conditions. The BPPD exhibits large linear dynamic ranges of over 100 dB for both positive and negative photocurrent conditions, with noise equivalent powers as low as 0.1 nW cm−2. By modulating the photocurrent with intensities and wavelengths of incident lights, five basic optical-modulated logic operations (“OR,” “AND,” “NOR,” “NOT,” and “NAND”) have been demonstrated with a single BPPD. Moreover, a dual-channel image transmission system featuring encrypted optical communication is realized using a single BPPD.