Tetraphenylmethane-based nonconjugated bipolar hosts with tunable donor-acceptor ratios for high-performance phosphorescent and TADF OLEDs.
- 1Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University Xi'an 710119 China [email protected].
- 2Key Laboratory of Yunnan Provincial Higher Education Institutions for Optoelectronics Device Engineering, School of Physics and Astronomy, Yunnan University Kunming 650500 China.
Abstract
The development of versatile host materials that combine high triplet energy, efficient bipolar charge transport, and excellent morphological stability remains essential for realizing high-performance organic light-emitting diodes (OLEDs). Herein, three nonconjugated bipolar host materials, Cz-TBI, DCz-DBI, and TCz-BI, were designed and synthesized by integrating carbazole donor units and benzo[d]imidazole acceptor units through a tetrahedral tetraphenylmethane (TPM) core. Varying the donor-to-acceptor ratio enabled systematic regulation of the charge-transport properties of the host materials. All three compounds exhibited excellent thermal stability, with decomposition temperatures above 500 °C, high glass transition temperatures of 170-187 °C, smooth amorphous films, and a high triplet energy of 3.02 eV. Hole-only and electron-only device measurements confirmed their bipolar charge-transport characteristics and demonstrated that the carrier-transport properties could be tuned by adjusting the donor-to-acceptor ratio. The compounds were evaluated as universal hosts in blue TADF OLEDs and blue, green, and red phosphorescent OLEDs (PhOLEDs). Among them, DCz-DBI delivered the best device performance, achieving maximum external quantum efficiencies (EQEs) of 22.7% for the blue TADF OLED and 21.5%, 24.3%, and 21.3% for the blue, green, and red PhOLEDs, respectively. A single-host white OLED based on DCz-DBI achieved a maximum EQE of 24.2%, an EQE of 22.4% at 1000 cd m-2, and a color-rendering index of 81, with negligible voltage-dependent color variation. These results establish TPM as an effective core for constructing versatile host materials for high-performance multicolor OLEDs.
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BibTeX
@article{zhang2026tetraphenylmethanebased,
title = {{Tetraphenylmethane-based nonconjugated bipolar hosts with tunable donor-acceptor ratios for high-performance phosphorescent and TADF OLEDs.}},
author = {Jinyan Zhang and Changsheng Shi and Shengjie Li and Qi Li and Zeyan Hui and Ning Sun and Qiang Wang},
journal = {Chemical science},
year = {2026},
month = oct,
doi = {10.1039/d6sc06678j},
url = {https://europepmc.org/article/MED/42953437},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Tetraphenylmethane-based nonconjugated bipolar hosts with tunable donor-acceptor ratios for high-performance phosphorescent and TADF OLEDs.
AU - Jinyan Zhang
AU - Changsheng Shi
AU - Shengjie Li
AU - Qi Li
AU - Zeyan Hui
AU - Ning Sun
AU - Qiang Wang
PY - 2026
DA - 2026/10/26
JO - Chemical science
DO - 10.1039/d6sc06678j
UR - https://europepmc.org/article/MED/42953437
AB - The development of versatile host materials that combine high triplet energy, efficient bipolar charge transport, and excellent morphological stability remains essential for realizing high-performance organic light-emitting diodes (OLEDs). Herein, three nonconjugated bipolar host materials, Cz-TBI, DCz-DBI, and TCz-BI, were designed and synthesized by integrating carbazole donor units and benzo[d]imidazole acceptor units through a tetrahedral tetraphenylmethane (TPM) core. Varying the donor-to-acceptor ratio enabled systematic regulation of the charge-transport properties of the host materials. All three compounds exhibited excellent thermal stability, with decomposition temperatures above 500 °C, high glass transition temperatures of 170-187 °C, smooth amorphous films, and a high triplet energy of 3.02 eV. Hole-only and electron-only device measurements confirmed their bipolar charge-transport characteristics and demonstrated that the carrier-transport properties could be tuned by adjusting the donor-to-acceptor ratio. The compounds were evaluated as universal hosts in blue TADF OLEDs and blue, green, and red phosphorescent OLEDs (PhOLEDs). Among them, DCz-DBI delivered the best device performance, achieving maximum external quantum efficiencies (EQEs) of 22.7% for the blue TADF OLED and 21.5%, 24.3%, and 21.3% for the blue, green, and red PhOLEDs, respectively. A single-host white OLED based on DCz-DBI achieved a maximum EQE of 24.2%, an EQE of 22.4% at 1000 cd m-2, and a color-rendering index of 81, with negligible voltage-dependent color variation. These results establish TPM as an effective core for constructing versatile host materials for high-performance multicolor OLEDs.
SN - 2041-6520
SN - 2041-6539
ER -