Amplifying electrical outputs of polyaniline-based Schottky DC generators through single polarity charge injection

Abstract

Schottky direct-current (DC) generators have gained attention for their ability to produce DC output directly without rectification. However, a major challenge is their limited voltage output, often below 1 V, and difficulty in simultaneously increasing both voltage and current outputs. This study develops a new design concept to improve the voltage and current outputs of a conducting polymer/metal Schottky DC generator by injecting a single type of charges from the Schottky unit's exterior to either its semiconductor or metal components. By utilizing a polyaniline-coated fabric and a metal Al plate to create a Schottky DC generator, as well as a single-mode triboelectric device such as PTFE film/metal Al, PTFE film/PA6 nanofiber membrane, or PA6-Ni/Cu plate as the external charge supplier, we demonstrate that injecting positive tribo charges to the Schottky Al electrode or negative charges to the polyaniline results in a significant increase in both the voltage and current outputs of the Schottky generator. The resultant Schottky unit showcased an exceptional peak open circuit voltage increasing to 4.88 ± 0.20 V, and an equally impressive peak short circuit current output peaking at 154.97 ± 5.20 μA (6.20 ± 0.21 μA/cm2). Remarkably, this configuration delivered an outstanding power density of up to 7.37 μW/cm2. These output metrics surpass those of standalone PANI/Al Schottky DC generator counterparts (1.09 ± 0.03 V, 67.32 ± 6.52 μA, and 0.66 μW/cm²), and also surpass most other Schottky DC generators previously reported. Incorporating nano Coulombs of charge into the Schottky generator resulted in an impressive micro Coulombs of charge migration within the Schottky device, achieving a remarkable fourfold amplification of voltage outputs and twofold amplification of current outputs, all while preserving the inherent DC output characteristics intrinsic to Schottky generators. Moreover, we have observed that the amount external tribo charges have a direct relationship with the voltage and current output increases of the Schottky DC generators. These phenomena were consistent, whether introducing positive charges to the Al layer of the Schottky unit or infusing negative charges into the polyaniline layer. Furthermore, alternative triboelectric devices connected to the Schottky generators yielded similar outcomes, thereby corroborating the robustness of our approach. This novel approach shows promise in enhancing power generation efficiency in Schottky DC generators and has potential applications in various fields requiring efficient and direct DC power generation.