TY - JOUR
T1 - High-sensitivity broadband colloidal quantum dot heterojunction photodetector for night-sky radiation
AU - Xu, Junfeng
AU - Wang, Haowei
AU - Yang, Shengyi
AU - Ni, Guoqiang
AU - Zou, Bingsuo
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/10/5
Y1 - 2018/10/5
N2 - Being with excellent photosensibility, bandgap tunability and solution processibility, lead sulfide (PbS) colloidal quantum dot (CQD) gets one of the most attracting nanomaterials for photodetectors and light-harvesting devices. Usually short ligands are used to passivate the surface of CQDs to enhance the carrier mobility in QD films, and different types of ligands show distinct influence on the physical/electrical properties on the passivated CQD films. In this paper, a high-sensitivity broadband photodetector based on PbS-EDT/PbS-TBAl heterojunction by band-alignment engineering was presented. After optimizing the thickness of PbS CQD films, we found that the maximum specific detectivity of the photodiode ITO/ZnO(40 nm)/PbS-TBAl(160 nm)/PbS-EDT(40 nm)/Au reached to 3.93 × 1013 Jones and 5.52 × 1013 Jones under 2.0 μW/cm2 910 nm and 1.9 μW/cm2 500 nm illuminations, respectively, showing excellent stability in air and high sensitivity to weak signal (i.e. night-sky radiation). Further, the device performance of photodiode ITO/ZnO/PbS-TBAl/PbS-EDT/Au is compared with that of the control device ITO/ZnO/PbS-TBAI/Au, and the underneath mechanism for the enhanced performance is discussed.
AB - Being with excellent photosensibility, bandgap tunability and solution processibility, lead sulfide (PbS) colloidal quantum dot (CQD) gets one of the most attracting nanomaterials for photodetectors and light-harvesting devices. Usually short ligands are used to passivate the surface of CQDs to enhance the carrier mobility in QD films, and different types of ligands show distinct influence on the physical/electrical properties on the passivated CQD films. In this paper, a high-sensitivity broadband photodetector based on PbS-EDT/PbS-TBAl heterojunction by band-alignment engineering was presented. After optimizing the thickness of PbS CQD films, we found that the maximum specific detectivity of the photodiode ITO/ZnO(40 nm)/PbS-TBAl(160 nm)/PbS-EDT(40 nm)/Au reached to 3.93 × 1013 Jones and 5.52 × 1013 Jones under 2.0 μW/cm2 910 nm and 1.9 μW/cm2 500 nm illuminations, respectively, showing excellent stability in air and high sensitivity to weak signal (i.e. night-sky radiation). Further, the device performance of photodiode ITO/ZnO/PbS-TBAl/PbS-EDT/Au is compared with that of the control device ITO/ZnO/PbS-TBAI/Au, and the underneath mechanism for the enhanced performance is discussed.
KW - Band-alignment engineering
KW - Colloidal quantum dots (CQDs)
KW - Heterojunction
KW - Lead sulfide (PbS)
KW - Ligand exchange
KW - Photodetector
UR - http://www.scopus.com/inward/record.url?scp=85048553074&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2018.06.105
DO - 10.1016/j.jallcom.2018.06.105
M3 - Article
AN - SCOPUS:85048553074
SN - 0925-8388
VL - 764
SP - 446
EP - 451
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
ER -