title: Triumphing over Charge Transfer Limitations of PEDOT Nanofiber Reduction Catalyst by 1,2-Ethanedithiol Doping for Quantum Dot Solar Cells.
abstract: Charge transfer between a conducting polymer-based counter electrode (CE) and a polysulfide (S2-/Sn2-) electrolyte mediator is a key limitation to improvements of solar energy conversion efficiency (ECE) in quantum-dot-sensitized solar cells (QDSCs). In this paper, 1,2-ethanedithiol (EDT) was doped into nanofibrous poly(3,4-ethylenedioxythiophene) (PEDOT NF) to overcome the charge transfer limitation between PEDOT NF and S2-/Sn2-. EDT not only helps to reduce the aggregation and thus enhance the linearization of the PEDOT chains but also changes the molecular conformation of the PEDOT chains from a benzoid to a quinoid structure. EDT-doped PEDOT NF-based CEs showed almost 3.7 times higher conductivity, better electrocatalytic activity, and improved compatibility with S2-/Sn2-in an aqueous electrolyte. As a result, the charge transfer resistance between the polymer-based CE and the S2-/Sn2-electrolyte was significantly reduced, resulting in over 3% ECE in QDSCs, more than double that of a bare PEDOT NF-based CE.
authors.forename: Tea-Yon
authors.initials: TY
authors.lastname: Kim
authors.forename: Tae Kyung
authors.initials: TK
authors.lastname: Lee
authors.forename: Byung Su
authors.initials: BS
authors.lastname: Kim
authors.forename: Seul Chan
authors.initials: SC
authors.lastname: Park
authors.forename: Sungjin
authors.initials: S
authors.lastname: Lee
authors.forename: Seung Soon
authors.initials: SS
authors.lastname: Im
authors.affiliation: Institute of Advanced Materials (INAM), Universitat Jaume I , 12006 Castelló, Spain.|Department of Chemistry, Faculty of Science, King Abdulaziz University , 21589 Jeddah, Saudi Arabia.
authors.forename: Juan
authors.identifier: http://orcid.org/0000-0003-4987-4887
authors.initials: J
authors.lastname: Bisquert
authors.forename: Yong Soo
authors.identifier: http://orcid.org/0000-0003-4989-321X
authors.initials: YS
authors.lastname: Kang
keywords: PEDOT; charge transfer limitation; doping; flexible device; metal-free reduction catalyst; quantum dot solar cells