TY - JOUR
T1 - Metal-Free Tetrathienoacene Sensitizers for High-Performance Dye-Sensitized Solar Cells
AU - Zhou, Nanjia
AU - Prabakaran, Kumaresan
AU - Lee, Byunghong
AU - Chang, Sheng Hsiung
AU - Harutyunyan, Boris
AU - Guo, Peijun
AU - Butler, Melanie R.
AU - Timalsina, Amod
AU - Bedzyk, Michael J.
AU - Ratner, Mark A.
AU - Vegiraju, Sureshraju
AU - Yau, Shuehlin
AU - Wu, Chun Guey
AU - Chang, Robert P H
AU - Facchetti, Antonio
AU - Chen, Ming Chou
AU - Marks, Tobin J.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/4/8
Y1 - 2015/4/8
N2 - A new series of metal-free organic chromophores (TPA-TTAR-A (1), TPA-T-TTAR-A (2), TPA-TTAR-T-A (3), and TPA-T-TTAR-T-A (4)) are synthesized for application in dye-sensitized solar cells (DSSC) based on a donor-π-bridge-acceptor (D-π-A) design. Here a simple triphenylamine (TPA) moiety serves as the electron donor, a cyanoacrylic acid as the electron acceptor and anchoring group, and a novel tetrathienoacene (TTA) as the π-bridge unit. Because of the extensively conjugated TTA π-bridge, these dyes exhibit high extinction coefficients (4.5-5.2 × 104 M-1 cm-1). By strategically inserting a thiophene spacer on the donor or acceptor side of the molecules, the electronic structures of these TTA-based dyes can be readily tuned. Furthermore, addition of a thiophene spacer has a significant influence on the dye orientation and self-assembly modality on TiO2 surfaces. The insertion of a thiophene between the π-bridge and the cyanoacrylic acid anchoring group in TPA-TTAR-T-A (dye 3) promotes more vertical dye orientation and denser packing on TiO2 (molecular footprint = 79 Å2), thus enabling optimal dye loading. Using dye 3, a DSSC power conversion efficiency (PCE) of 10.1% with Voc = 0.833 V, Jsc = 16.5 mA/cm2, and FF = 70.0% is achieved, among the highest reported to date for metal-free organic DSSC sensitizers using an I-/I3- redox shuttle. Photophysical measurements on dye-grafted TiO2 films reveal that the additional thiophene unit in dye 3 enhances the electron injection efficiency, in agreement with the high quantum efficiency.
AB - A new series of metal-free organic chromophores (TPA-TTAR-A (1), TPA-T-TTAR-A (2), TPA-TTAR-T-A (3), and TPA-T-TTAR-T-A (4)) are synthesized for application in dye-sensitized solar cells (DSSC) based on a donor-π-bridge-acceptor (D-π-A) design. Here a simple triphenylamine (TPA) moiety serves as the electron donor, a cyanoacrylic acid as the electron acceptor and anchoring group, and a novel tetrathienoacene (TTA) as the π-bridge unit. Because of the extensively conjugated TTA π-bridge, these dyes exhibit high extinction coefficients (4.5-5.2 × 104 M-1 cm-1). By strategically inserting a thiophene spacer on the donor or acceptor side of the molecules, the electronic structures of these TTA-based dyes can be readily tuned. Furthermore, addition of a thiophene spacer has a significant influence on the dye orientation and self-assembly modality on TiO2 surfaces. The insertion of a thiophene between the π-bridge and the cyanoacrylic acid anchoring group in TPA-TTAR-T-A (dye 3) promotes more vertical dye orientation and denser packing on TiO2 (molecular footprint = 79 Å2), thus enabling optimal dye loading. Using dye 3, a DSSC power conversion efficiency (PCE) of 10.1% with Voc = 0.833 V, Jsc = 16.5 mA/cm2, and FF = 70.0% is achieved, among the highest reported to date for metal-free organic DSSC sensitizers using an I-/I3- redox shuttle. Photophysical measurements on dye-grafted TiO2 films reveal that the additional thiophene unit in dye 3 enhances the electron injection efficiency, in agreement with the high quantum efficiency.
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U2 - 10.1021/ja513254z
DO - 10.1021/ja513254z
M3 - Article
C2 - 25768124
AN - SCOPUS:84926435175
SN - 0002-7863
VL - 137
SP - 4414
EP - 4423
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 13
ER -