Novel p–p Heterojunctions Self-Powered Broadband Photodetectors with Ultrafast Speed and High Responsivity

Abstract

Novel inorganic/organic self-powered UV–vis photodetectors based on single Se microtube and conducting polymers—polyaniline (PANI), polypyrrole (PPy), and poly(3,4-ethylenedioxythiophene) (PEDOT)—are fabricated. The conducting polymers are directly coated on the surface of a single Se microtube via a facile and low-cost in situ polymerization method. The integrated Se/PANI photodetector with 45-nm-thick PANI layer shows excellent self-powered behavior under UV–vis light illumination. In particular, it exhibits high on/off ratio of 1.1 × 103, responsivity (120 mA W−1), large detectivity (3.78 × 1011 Jones), and ultrafast response speed (rise time of 4.5 µs and fall time of 2.84 ms) at zero bias at 610 nm (0.434 mW cm−2)-light illumination. Moreover, the individual Se/PPy and Se/PEDOT self-powered photodetectors also exhibit fast and stable responses, including responsivity of 70 and 5.5 mA W−1, rise time of 0.35 and 1.00 ms, fall time of 16.97 and 9.78 ms, respectively. Given the simple device architecture and low cost fabrication process, this work provides a promising way to fabricate inorganic/organic, high-performance, self-powered photodetectors.