title: Dual use of tantalum disulfides as hole and electron extraction layers in organic photovoltaic cells.
abstract: UV/ozone treated (UVO-treated) TaS2 and non-treated TaS2 nanosheets are introduced into organic photovoltaic cells (OPVs) as hole extraction layers (HEL) and electron extraction layers (EEL). TaS2 nanosheets are obtained via ultrasonic vibration and size-controlled by centrifugation. Atomic force microscopy (AFM) images reveal that the thickness and lateral size of TaS2 nanosheets are approximately 1 and 70 nm, indicating that uniform and ultrathin TaS2 nanosheets are obtained. The work function of TaS2 increases from 4.4 eV to 4.9-5.1 eV after applying UVO treatment by forming Ta2O5. In addition, the power conversion efficiencies of normal OPV with UVO-treated TaS2 and inverted OPV with TaS2 are 3.06 and 2.73%, which are higher than those of OPV without TaS2 (1.56% for normal OPV and 0.22% for inverted OPV). These results indicate that TaS2 is a promising material for HEL and EEL layers in OPVs.
authors.affiliation: School of Chemical Engineering and Materials Science, Chung-Ang University, 221, Heukseok-dong, Dongjak-gu, Seoul 156-756, Republic of Korea. sooyoungkim@cau.ac.kr.
authors.forename: Quyet Van
authors.initials: QV
authors.lastname: Le
authors.forename: Thang Phan
authors.initials: TP
authors.lastname: Nguyen
authors.forename: Kyoung Soon
authors.initials: KS
authors.lastname: Choi
authors.forename: Yoon-Ho
authors.initials: YH
authors.lastname: Cho
authors.forename: Young Joon
authors.initials: YJ
authors.lastname: Hong
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Kim