Laser-enabled dual-state transformation on PANI:PSS/Si for wavelength-selective detection

Abstract

Position-sensitive detectors are widely used in industry due to accurate sensing of changes in light position. The introduction of additional wavelength selectors can cause deviations in light position and affect the performance of the devices. In this work, an organic–inorganic heterojunction of polyaniline-poly (p-styrenesulfonic acid) (PANI:PSS)/p-Si is proposed to achieve selective detection at optical wavelengths using the lateral photovoltaic effect. The maximum reduction of sensitivity in the detection of 405 nm laser can reach up to 127.59 mV/mm, with a decrease in about 99%. When the device is exposed to blue-violet light, the absorption layer changes from a Si layer to a PANI:PSS layer, which weakens the photon utilization efficiency and charges carrier transport. The self-generated longitudinal voltage further enhances the absorption of the PANI:PSS layer for blue-violet light. PANI absorbs photon energy to generate electron–hole pairs and transitions from the reduced state to the oxidized state in the depletion region at the contact interface. The oxide layer hinders carrier separation and increases carrier recombination. Due to the inherent properties of the structure, the wavelength selection function is realized by the detector itself, enriching its original single function. The sensitivity in other light bands has been improved, including more than three times at 520 nm compared to p-Si. These results have provided the theoretical foundation for highly selective and tunable optoelectronic devices while helping to overcome the challenges of high manufacturing costs and customized application scenarios. They provide a viable solution for the intelligent development of optoelectronic devices.