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Ultrasensitive PbS‐Quantum‐Dot Photodetectors for Visible–Near‐Infrared Light Through Surface Atomic‐Ligand Exchange
Author(s) -
Mi Longfei,
Yu Yongqiang,
Wang Hui,
Zhang Yan,
Yao Xudong,
Chang Yajing,
Wang Xiaoming,
Jiang Yang
Publication year - 2015
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201500138
Subject(s) - photodetector , quantum dot , optoelectronics , photosensitivity , materials science , infrared , visible spectrum , optics , physics
A surface atomic‐ligand exchange method is applied the first time in the construction of photodetectors (PDs) based on PbS quantum dots (QDs) for ultrasensitivity. The device thus produces a high photosensitivity to visible and near‐infrared light with a photoresponsivity up to 7.5 × 10 3 A W −1 and a high stability in air. In particular, these PbS‐QD‐based PDs show the capability of following a pulse light with a frequency up to 100 kHz well at a relatively fast response time/recovery time of ≈4/40 μs, much faster than most previous QD‐based PDs. The short response time is attributed to modification for the surface of the PbS‐QDs by cetyltrimethylammonium bromide treatment, which effectively improves the contact between the QDs and the Au electrodes, leading to extracting a high carrier mobility (≈0.142 cm 2 V −1 s −1 ). These findings show the great potential of PbS‐QDs as high‐speed nano‐photodetectors, and, more importantly, demonstrate the importance of the surface atomic‐ligand exchange method in the construction of QD‐based devices.