TY - JOUR
T1 - Precise Control of Thermal and Redox Properties of Organic Hole-Transport Materials
AU - Chiykowski, Valerie A.
AU - Cao, Yang
AU - Tan, Hairen
AU - Tabor, Daniel P.
AU - Sargent, Edward H.
AU - Aspuru-Guzik, Alán
AU - Berlinguette, Curtis P.
N1 - Publisher Copyright:
© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
PY - 2018/11/19
Y1 - 2018/11/19
N2 - We report design principles of the thermal and redox properties of synthetically accessible spiro-based hole transport materials (HTMs) and show the relevance of these findings to high-performance perovskite solar cells (PSCs). The chemical modification of an asymmetric spiro[fluorene-9,9′-xanthene] core is amenable to selective placement of redox active triphenylamine (TPA) units. We therefore leveraged computational techniques to investigate five HTMs bearing TPA groups judiciously positioned about this asymmetric spiro core. It was determined that TPA groups positioned about the conjugated fluorene moiety increase the free energy change for hole-extraction from the perovskite layer, while TPAs about the xanthene unit govern the Tg values. The synergistic effects of these characteristics resulted in an HTM characterized by both a low reduction potential (≈0.7 V vs. NHE) and a high Tg value (>125 °C) to yield a device power conversion efficiency (PCE) of 20.8 % in a PSC.
AB - We report design principles of the thermal and redox properties of synthetically accessible spiro-based hole transport materials (HTMs) and show the relevance of these findings to high-performance perovskite solar cells (PSCs). The chemical modification of an asymmetric spiro[fluorene-9,9′-xanthene] core is amenable to selective placement of redox active triphenylamine (TPA) units. We therefore leveraged computational techniques to investigate five HTMs bearing TPA groups judiciously positioned about this asymmetric spiro core. It was determined that TPA groups positioned about the conjugated fluorene moiety increase the free energy change for hole-extraction from the perovskite layer, while TPAs about the xanthene unit govern the Tg values. The synergistic effects of these characteristics resulted in an HTM characterized by both a low reduction potential (≈0.7 V vs. NHE) and a high Tg value (>125 °C) to yield a device power conversion efficiency (PCE) of 20.8 % in a PSC.
KW - glass transition temperature
KW - hole-transport materials
KW - organic semiconductors
KW - perovskite solar cells
KW - solar energy
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U2 - 10.1002/anie.201810809
DO - 10.1002/anie.201810809
M3 - Article
C2 - 30267466
AN - SCOPUS:85055539176
SN - 1433-7851
VL - 57
SP - 15529
EP - 15533
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 47
ER -
