Metalloid tellurium-doped graphene nanoplatelets as ultimately stable electrocatalysts for dye-sensitized solar cells

Abstract

aSchool of Energy and Chemical Engineering/Center for Dimmension-Controllable Organic Frameworks, Ulsan National Institute of Science and Technology (UNIST), 50, UNIST, Ulsan 44919, Republic of Korea E-mail:jmj12@ unist.ac.kr, jbbaek@unist.ac.kr Boo Jae Jang,a In-Yup Jeon a, Myung Jong Ju a* and Jong Beom Baeka* Abstract One feasible alternative to Pt catalyst in dye-sensitized solar cells (DSSCs) is metalloid tellurium (Te)- doped graphene nanoplatelets (TeGnPs). These were prepared by ball-milling graphite in the presence of Te crystals. Introduction of Te at the edges of TeGnPs was confirmed with various analytical techniques including time of flight secondary ion mass spectrometry (TOF-SIMS). The resultant TeGnPs are herein evaluated as counter electrode (CE) materials for the cobalt reduction reaction (CRR) in DSSCs. TeGnP-CE exhibits much lower charge transfer resistance (Rct=0.15 Ω cm2 ) than that (Rct=1.77 Ω cm2 ) of Pt-CE. More importantly, TeGnP-CE displays an extreme electrochemical stability for the Co(bpy)3 2+/3+ (bpy=2,2'-bipyridine) redox couple even after 1000 potential cycles. The SM315-based DSSC fabricated with TeGnP-CE shows a better power conversion efficiency (PCE=11.58%) than that with Pt-CE (11.03%), suggesting that TeGnP-CE could be one of the best alternatives to Pt-CE in DSSCs.