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Ternary Blended Fullerene‐Free Polymer Solar Cells with 16.5% Efficiency Enabled with a Higher‐LUMO‐Level Acceptor to Improve Film Morphology
Author(s) -
Li Kun,
Wu Yishi,
Tang Yabing,
Pan MingAo,
Ma Wei,
Fu Hongbing,
Zhan Chuanlang,
Yao Jiannian
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201901728
Subject(s) - materials science , acceptor , ternary operation , homo/lumo , open circuit voltage , fullerene , crystallinity , polymer solar cell , organic solar cell , short circuit , active layer , solar cell , band gap , electron mobility , photoactive layer , polymer , optoelectronics , nanotechnology , layer (electronics) , voltage , organic chemistry , chemistry , molecule , composite material , physics , thin film transistor , quantum mechanics , computer science , programming language , condensed matter physics
Ternary approaches to solar cell design utilizing a small bandgap nonfullerene acceptor as the near infrared absorber to increase the short‐circuit current density always decreases the open‐circuit voltage. Herein, a highly efficient polymer solar cell with an impressive efficiency of 16.28 ± 0.20% enabled by an effective voltage‐increased ternary blended fullerene‐free material approach is reported. In this approach, the structural similarity between the host and the higher‐LUMO‐level guest enables the two acceptors to be synergized, obtaining increased open‐circuit voltage and fill factor and a small increase of short‐circuit current density. The same beneficial effects are demonstrated by using two host binary systems. The homogeneous fine film morphologies and the π–π stacking patterns of the host blend are well maintained, while larger donor and acceptor phases and increased lamellar crystallinity, increased charge mobilities, and reduced monomolecular recombination can be achieved upon addition of the guest nonfullerene acceptor. The increased charge mobilities and reduced monomolecular recombination not only contribute to the improved fill factor but also enable the best devices to be fabricated with a relatively thicker ternary blended active layer (110 vs 100 nm). This, combined with the absorption from the added guest acceptor, contribute to the increased short‐circuit current.