Solution-Processed PbSe Colloidal Quantum Dot-Based Near-Infrared Photodetector

Abstract

A solution-processed near-infrared (NIR) photodetector based on PbSe colloidal quantum dots (CQDs) with a field-effect transistor (FET) configuration was presented. By blending PbSe CQDs into poly(3-hexylthiophene-2, 5-diyl) (P3HT) as active layer, the photosensitive spectrum of P3HT:PbSe nanocomposites extends into the NIR region. The responsivity and the specific detectivity of FET-based photodetector Au(gate)/PMMA (930nm)/P3HT:PbSe(55nm)/Au(source, drain) reached 500 A/W and 5.02 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> Jones, respectively, at V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> = -40 V and V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> = -40 V with 40 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of 980-nm laser illumination. It gets more stable due to its reverse fabrication using the dielectric layer to cover the active layer from environment air.