TY - JOUR
T1 - Enhanced power conversion efficiency via hybrid ligand exchange treatment of p-Type PbS quantum dots
AU - Teh, Zhi Li
AU - Hu, Long
AU - Zhang, Zhilong
AU - Gentle, Angus R.
AU - Chen, Zihan
AU - Gao, Yijun
AU - Yuan, Lin
AU - Hu, Yicong
AU - Wu, Tom
AU - Huang, Shujuan
AU - Patterson, Robert J.
PY - 2020/5/20
Y1 - 2020/5/20
N2 - PbS quantum dot solar cells (QDSCs) have emerged as a promising low-cost, solution-processable solar energy harvesting device and demonstrated good air stability and potential for large-scale commercial implementation. PbS QDSCs achieved a record certified efficiency of 12% in 2018 by utilizing an n+-n-p device structure. However, the p-type layer has generally suffered from low carrier mobility due to the organic ligand 1,2-ethanedithiol (EDT) that is used to modify the quantum dot (QD) surface. The low carrier mobility of EDT naturally limits the device thickness as the carrier diffusion length is limited by the low mobility. Herein, we improve the properties of the p-type layer through a two-step hybrid organic ligand treatment. By treating the p-type layer with two types of ligands, 3-mercaptopropionic acid (MPA) and EDT, the PbS QD surface was passivated by a combination of the two ligands, resulting in an overall improvement in open-circuit voltage, fill factor, and current density, leading to an improvement in the cell efficiency from 7.0 to 10.4% for the champion device. This achievement was a result of the improved QD passivation and a reduction in the interdot distance, improving charge transport through the p-type PbS quantum dot film.[Graph presents]
AB - PbS quantum dot solar cells (QDSCs) have emerged as a promising low-cost, solution-processable solar energy harvesting device and demonstrated good air stability and potential for large-scale commercial implementation. PbS QDSCs achieved a record certified efficiency of 12% in 2018 by utilizing an n+-n-p device structure. However, the p-type layer has generally suffered from low carrier mobility due to the organic ligand 1,2-ethanedithiol (EDT) that is used to modify the quantum dot (QD) surface. The low carrier mobility of EDT naturally limits the device thickness as the carrier diffusion length is limited by the low mobility. Herein, we improve the properties of the p-type layer through a two-step hybrid organic ligand treatment. By treating the p-type layer with two types of ligands, 3-mercaptopropionic acid (MPA) and EDT, the PbS QD surface was passivated by a combination of the two ligands, resulting in an overall improvement in open-circuit voltage, fill factor, and current density, leading to an improvement in the cell efficiency from 7.0 to 10.4% for the champion device. This achievement was a result of the improved QD passivation and a reduction in the interdot distance, improving charge transport through the p-type PbS quantum dot film.[Graph presents]
KW - PbS quantum dot
KW - quantum dot solar cell
KW - p-type layer
KW - ligand exchange
KW - interdot distance
UR - http://www.scopus.com/inward/record.url?scp=85085533868&partnerID=8YFLogxK
U2 - 10.1021/acsami.9b23492
DO - 10.1021/acsami.9b23492
M3 - Article
C2 - 32347092
AN - SCOPUS:85085533868
VL - 12
SP - 22751
EP - 22759
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
SN - 1944-8244
IS - 20
ER -