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Self‐Organization of Polymer Additive, Poly(2‐vinylpyridine) via One‐Step Solution Processing to Enhance the Efficiency and Stability of Polymer Solar Cells
Author(s) -
Lee Wonho,
Jeong Seonju,
Lee Changyeon,
Han Gibok,
Cho Changsoon,
Lee JungYong,
Kim Bumjoon J.
Publication year - 2017
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.201602812
Subject(s) - materials science , polymer solar cell , active layer , polymer , cathode , chemical engineering , work function , energy conversion efficiency , photoactive layer , layer (electronics) , optoelectronics , nanotechnology , composite material , chemistry , engineering , thin film transistor
Interfaces between the photoactive layers and electrodes play critical roles in controlling the performance of optoelectronic devices. Herein, a novel nonconjugated polymer additive (nPA), poly(2‐vinylpyridine) (P2VP), is reported for modifying the interfaces between the bulk‐heterojunction (BHJ) and cathode/metal oxide (MO) layers. The P2VP nPA enables remarkably enhanced power conversion efficiencies (PCEs) and ambient stability in different types of polymer solar cells (PSCs). Importantly, interfacial engineering can be achieved during deposition of the P2VP nPA‐containing BHJ active layer via simple, one‐step solution processing. The P2VP nPA has much higher surface energy than the BHJ active components and stronger interaction with the surface of MO, which affords spontaneous vertical phase separation from the BHJ layer on the MO surface by one‐step solution processing. The self‐assembled P2VP layer substantially reduces the work function and surface defect density of MO, thereby minimizing the charge‐extraction barrier and increasing the PCEs of the PSCs significantly, i.e., PTB7‐Th:PC 71 BM (10.53%→11.14%), PTB7:PC 71 BM (7.37%→8.67%), and PTB7‐Th:P(NDI2HD‐T) all‐PSCs (5.52%→6.14%). In addition, the lifetimes of the PSCs are greatly improved by the use of the P2VP nPA.