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Investigation of Charge Carrier Behavior in High Performance Ternary Blend Polymer Solar Cells
Author(s) -
Lee Tack Ho,
Uddin Mohammad Afsar,
Zhong Chengmei,
Ko SeoJin,
Walker Bright,
Kim Taehyo,
Yoon Yung Jin,
Park Song Yi,
Heeger Alan J.,
Woo Han Young,
Kim Jin Young
Publication year - 2016
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.201600637
Subject(s) - ternary operation , materials science , polymer solar cell , polymer , open circuit voltage , x ray photoelectron spectroscopy , charge carrier , ultraviolet photoelectron spectroscopy , absorption (acoustics) , energy conversion efficiency , chemical engineering , ternary numeral system , polymer blend , analytical chemistry (journal) , heterojunction , electron mobility , optoelectronics , voltage , copolymer , organic chemistry , composite material , chemistry , electrical engineering , computer science , programming language , engineering
This study demonstrates high‐performance, ternary‐blend polymer solar cells by modifying a binary blend bulk heterojunction (PPDT2FBT:PC 71 BM) with the addition of a ternary component, PPDT2CNBT. PPDT2CNBT is designed to have complementary absorption and deeper frontier energy levels compared to PPDT2FBT, while being based on the same polymeric backbone. A power conversion efficiency of 9.46% is achieved via improvements in both short‐circuit current density ( J SC ) and open‐circuit voltage ( V OC ). Interestingly, the V OC increases with increasing the PPDT2CNBT content in ternary blends. In‐depth studies using ultraviolet photoelectron spectroscopy and transient absorption spectroscopy indicate that the two polymers are not electronically homogeneous and function as discrete light harvesting species. The structural similarity between PPDT2CNBT and PPDT2FBT allows the merits of a ternary system to be fully utilized to enhance both J SC and V OC without detriment to fill‐factor via minimized disruption of semi‐crystalline morphology of binary PPDT2FBT:PC 71 BM blend. Further, by careful analysis, charge carrier transport in this ternary blend is clearly verified to follow parallel‐like behavior.