TY - JOUR
T1 - Thick-Film High-Performance Bulk-Heterojunction Solar Cells Retaining 90% PCEs of the Optimized Thin Film Cells
AU - Yin, Hang
AU - Cheung, Sin Hang
AU - Ngai, Jenner H. L.
AU - Ho, Carr Hoi Yi
AU - Chiu, Ka Lok
AU - Hao, Xiaotao
AU - Li, Ho Wa
AU - Cheng, Yuanhang
AU - Tsang, Sai Wing
AU - So, Shu Kong
N1 - Funding Information:
Support for this work by the Research Grant Council of Hong Kong under Grant #HKBU211913, NSFC/RGC N-HKBU 202/16, and the Research Committee of HKBU under Grant #RC-ICRS/15-16/4A-SSK is gratefully acknowledged. X.T. Hao acknowledges the National Natural Science Foundation of China for the NSFC/RGC project (No. 61631166001).
Publisher copyright:
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2017/4/1
Y1 - 2017/4/1
N2 - Most optimized, high performance, bulk-heterojunction (BHJ) polymer solar cells have an active layer thickness of about 100 nm. The thin active layer is unfavorable for optical absorption and film coating. This contribution employs a ternary cell to address this problem. In this paper, thick BHJ cells can be fabricated that retain 90% power conversion efficiencies (PCEs) of the optimized thin-film cells. The BHJs under investigations are PTB7:PC71BM, PTB7-Th:PC71BM, and P3HT:PCBM. Into these BHJs, a ternary component, p-DTS(fbtth2)2 (DTS) is introduced. Without DTS, the binary thick-film devices (≈200, ≈200, and ≈400 nm) have PCEs of 6.3%, 7.4%, and 3.2%. With DTS, the corresponding BHJs have markedly improved PCEs of 7.6%, 8.3%, and 3.9%, respectively. The results are more than 90% the PCEs of the optimized binary BHJs. The origins of the improvement are investigated. Addition of the ternary component DTS enhances hole mobility and reduces trap states. Both observations are well correlated with improved fill factors of the ternary BHJ cells. Photothermal deflection spectroscopy and 1H nuclear magnetic resonance are used to trace the electronic and the nanoscale interactions of the DTS with the polymer and fullerene. The results suggest the DTS behaves as a conducting bridge in between two neighboring polymer segments.
AB - Most optimized, high performance, bulk-heterojunction (BHJ) polymer solar cells have an active layer thickness of about 100 nm. The thin active layer is unfavorable for optical absorption and film coating. This contribution employs a ternary cell to address this problem. In this paper, thick BHJ cells can be fabricated that retain 90% power conversion efficiencies (PCEs) of the optimized thin-film cells. The BHJs under investigations are PTB7:PC71BM, PTB7-Th:PC71BM, and P3HT:PCBM. Into these BHJs, a ternary component, p-DTS(fbtth2)2 (DTS) is introduced. Without DTS, the binary thick-film devices (≈200, ≈200, and ≈400 nm) have PCEs of 6.3%, 7.4%, and 3.2%. With DTS, the corresponding BHJs have markedly improved PCEs of 7.6%, 8.3%, and 3.9%, respectively. The results are more than 90% the PCEs of the optimized binary BHJs. The origins of the improvement are investigated. Addition of the ternary component DTS enhances hole mobility and reduces trap states. Both observations are well correlated with improved fill factors of the ternary BHJ cells. Photothermal deflection spectroscopy and 1H nuclear magnetic resonance are used to trace the electronic and the nanoscale interactions of the DTS with the polymer and fullerene. The results suggest the DTS behaves as a conducting bridge in between two neighboring polymer segments.
KW - enhanced hole mobility
KW - nuclear magnetic resonance measurement
KW - photothermal deflection spectroscopy
KW - ternary devices
KW - thick-film organic photovoltaic devices
UR - http://www.scopus.com/inward/record.url?scp=85015651366&partnerID=8YFLogxK
U2 - 10.1002/aelm.201700007
DO - 10.1002/aelm.201700007
M3 - Journal article
AN - SCOPUS:85015651366
SN - 2199-160X
VL - 3
JO - Advanced Electronic Materials
JF - Advanced Electronic Materials
IS - 4
M1 - 1700007
ER -
