TY - JOUR
T1 - Balanced Carrier Injection and Charge Separation of CuInS2 Quantum Dots for Bifunctional Light-Emitting and Photodetection Devices
AU - Chang, Shuai
AU - Zhao, Yeling
AU - Tang, Jialun
AU - Bai, Zelong
AU - Zhao, Liangyu
AU - Zhong, Haizheng
N1 - Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/3/26
Y1 - 2020/3/26
N2 - The ligand exchange of 6-mercaptohexanol on the surface CuInS2 quantum dots not only improves their solution processability in alcoholic solvents such as methanol, ethanol, and N,N-dimethylformamide but also modulates their electrical band gap and thus the charge injection and extraction at the charge transport interfaces. Bifunctional light-emitting and photodetection devices based on these alcohol-soluble CuInS2 quantum dots are realized adopting an inverted structure with ZnO as the electron transport layer and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(4,4′-(N-(4-butylphenyl)diphenylaminel)] and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate as the hole transport layers. The optimized device with selected active layer thickness exhibits red emission at 647 nm with a maximum luminance of 1600 cd/m2 under forward bias and works as a photodetector at zero bias with a maximum responsibility of 0.53 mA/W and detectivity of 2.5 × 1010 jones. Furthermore, with interface engineering of the polyethylenimine ethoxylated (PEIE) layer at the electron transport side, more balanced charge injection is achieved, leading to reducing electroluminescence roll-off effect. The insulating PEIE layer also blocks the current leakage, giving rise to reduced dark current and improved detectivity of 3.5 × 1010 jones. The effective bidirectional charge transfer achieved under simplified device design using the alcohol-soluble quantum dots brings a new candidate for multifunctional devices.
AB - The ligand exchange of 6-mercaptohexanol on the surface CuInS2 quantum dots not only improves their solution processability in alcoholic solvents such as methanol, ethanol, and N,N-dimethylformamide but also modulates their electrical band gap and thus the charge injection and extraction at the charge transport interfaces. Bifunctional light-emitting and photodetection devices based on these alcohol-soluble CuInS2 quantum dots are realized adopting an inverted structure with ZnO as the electron transport layer and poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(4,4′-(N-(4-butylphenyl)diphenylaminel)] and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate as the hole transport layers. The optimized device with selected active layer thickness exhibits red emission at 647 nm with a maximum luminance of 1600 cd/m2 under forward bias and works as a photodetector at zero bias with a maximum responsibility of 0.53 mA/W and detectivity of 2.5 × 1010 jones. Furthermore, with interface engineering of the polyethylenimine ethoxylated (PEIE) layer at the electron transport side, more balanced charge injection is achieved, leading to reducing electroluminescence roll-off effect. The insulating PEIE layer also blocks the current leakage, giving rise to reduced dark current and improved detectivity of 3.5 × 1010 jones. The effective bidirectional charge transfer achieved under simplified device design using the alcohol-soluble quantum dots brings a new candidate for multifunctional devices.
UR - http://www.scopus.com/inward/record.url?scp=85082744964&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.0c00723
DO - 10.1021/acs.jpcc.0c00723
M3 - Article
AN - SCOPUS:85082744964
SN - 1932-7447
VL - 124
SP - 6554
EP - 6561
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 12
ER -