Solution-Processed CH₃NH₃SnI₃ Lead-Free Hybrid-Perovskite Quantum Dots-Based MSM Photodetector

This article reports a solution-processed lead (Pb)-free methylammonium tin iodide (CH<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub>NH<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub>SnI<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub> or MASI) perovskite quantum dots (PQDs)-based metal–semiconductor–metal (MSM) photodetector. The synthesized MASI PQDs solution is spin coated on an indium tin oxide (ITO)-coated substrate to fabricate the Al/CH<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub>NH<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub>SnI<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>3</roman></sub>-film/ITO structure-based MSM photodetector under study. The analysis of transmission electron microscopy (TEM) image gives an average particle size of ~2.6 nm of the PQDs, and the UV–Vis measurements give an absorbance spectrum over 300–700 nm with a bandgap of ~1.92 eV of the MASI PQDs film. The optical measurements give the maximum responsivity, external quantum efficiency (EQE), and specific detectivity of the proposed device as 2.38 A/W (2.23 A/W), 766.5% (460.8%), and 1.23 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>12</roman></sup> Jones (1.152 × 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>12</roman></sup> Jones), respectively, at 385 nm (600 nm) under -1-V bias and light intensity of 9.9 mW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup> (5.8 mW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>2</roman></sup>). The proposed photodetector has a rise time and fall time of 0.57 s (0.25 s) and 0.32 s (0.37 s) at 385 nm (600 nm), respectively.