Multiple Optical Imaging Encryption Enabled by Giant Lateral Photovoltaic Response via Dual Noncentrosymmetry-Induced Gradient Band Alignment and the Pyro-Phototronic Effect

Traditional position-sensitive detectors (PSDs) are constrained by inefficient interface separation and transport of photogenerated carriers due to suboptimal band alignment, limiting their lateral photovoltaic effect (LPE) performance. Furthermore, effective mechanisms for harnessing the pyroelectric effect (PE) remain elusive. Here, we present a high-performance PSD leveraging gradient band engineering and enhanced pyroelectric coupling. By fabricating a Si nanowire array core–shell heterojunction with a dual-layer noncentrosymmetric CdS/ZnO structure, longitudinal carrier separation and lateral collection efficiency are significantly enhanced, resulting in exceptional LPE performance across 405–1064 nm with a static position sensitivity of 868.6 mV/mm and nonlinearity of only 4.2%. Moreover, the synergistic polarization fields generated by the dual pyroelectric materials are innovatively leveraged to facilitate carrier transport, further elevating the sensitivity to a record 15390 mV/mm with rapid response times of 117/134 μs. Remarkably, based on the spatial distribution characteristics of the PE-modulated LPE signals, a novel information encryption and transmission scheme is proposed. Besides, the PSD also demonstrates a large working distance, maintaining an ultrahigh sensitivity of 1083 mV/mm even at 6 mm. By exploiting the LPE’s dependence on electrode spacing and wavelength and incorporating dual-wavelength excitation, an optoelectronic image encryption and transmission system featuring multiple logic gates is implemented.