Transition Metal Ions Influence the Performance of Photodetector of Two‐Dimensional CdS Nanoplatelets

Abstract

Transition metal‐doped two‐dimensional (2D) semiconductor nanoplatelets (NPLs) with atomically precise thickness have attracted much research interest due to their inherent photo‐physical properties. In this work, we have synthesized 2D Cu‐doped CdS NPLs, investigated the charge transfer dynamics using ultrafast transient absorption spectroscopy, and fabricated an efficient photodetector device. A large Stoke’s shifted emission at ~685 nm with an average lifetime of about ~1.45 µs is observed in Cu‐doped CdS NPLs. Slower bleach recovery kinetics leads to large charge carrier separation in Cu‐doped NPLs which is beneficial for photodetector applications. Cu‐doped NPLs‐based photodetectors exhibit high photocurrent, fast response (~120 ms), ~600 times higher photoresponsivity, and ~300 times higher detectivity (~4.1×1013 Jones) than undoped CdS NPLs. These excellent properties of Cu‐doped CdS NPLs make this material an efficient alternative for next‐generation optoelectronic devices.