title: Rational Design of Dipolar Chromophore as an Efficient Dopant-Free Hole-Transporting Material for Perovskite Solar Cells.
abstract: In this paper, an electron donor-acceptor (D-A) substituted dipolar chromophore (BTPA-TCNE) is developed to serve as an efficient dopant-free hole-transporting material (HTM) for perovskite solar cells (PVSCs). BTPA-TCNE is synthesized via a simple reaction between a triphenylamine-based Michler's base and tetracyanoethylene. This chromophore possesses a zwitterionic resonance structure in the ground state, as evidenced by X-ray crystallography and transient absorption spectroscopies. Moreover, BTPA-TCNE shows an antiparallel molecular packing (i.e., centrosymmetric dimers) in its crystalline state, which cancels out its overall molecular dipole moment to facilitate charge transport. As a result, BTPA-TCNE can be employed as an effective dopant-free HTM to realize an efficient (PCE ≈ 17.0%) PVSC in the conventional n-i-p configuration, outperforming the control device with doped spiro-OMeTAD HTM.
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Zhong'an
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Zonglong
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Chu-Chen
authors.initials: CC
authors.lastname: Chueh
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Sae Byeok
authors.initials: SB
authors.lastname: Jo
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Jingdong
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Sei-Hum
authors.initials: SH
authors.lastname: Jang
authors.affiliation: Department of Materials Science and Engineering, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Alex K-Y
authors.initials: AK
authors.lastname: Jen