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High performance deep‐blue emitters with a Commission International de l'Eclairage (CIE) coordinate of CIEy≤0.08 are highly desired in ultrahigh‐definition displays. Herein, we designed and synthesized an efficient D–π–A deep‐blue emitter, 2‐(6‐([1,1′ : 3′,1′′‐terphenyl]‐5′‐yl)pyridin‐3‐yl)‐1‐phenyl‐1H‐phenanthro[9,10‐d] imidazole (mPTPH), using the synergistic effect of intramolecular hydrogen bond (H‐bond) and hybridized excited state. Single‐crystal structure analysis confirmed that there exist intra‐ and intermolecular H‐bond interactions which could inhibit the structure vibration and increase photoluminescence efficiency. The photophysical and theoretical results show that mPTPH exhibited hybridized local and charge‐transfer (HLCT) feature with strong deep‐blue emission. Ultimately, the non‐doped device based on mPTPH exhibited high maximum luminance of 20610 cd m−2. The doped device achieved high maximum external quantum efficiency of 5.4 % and small efficiency roll‐off with deep‐blue emission peak of 413 nm and CIE coordinate of (0.16, 0.08). [ABSTRACT FROM AUTHOR]

Chromophores with hybridized local and charge‐transfer (HLCT) excited state are promising for the realization of high performance blue organic light‐emitting diodes (OLEDs). The rational manipulation of HLCT excited state for efficient emitters remains challenging. Herein, we present three donor‐π‐acceptor (D‐π‐A) molecules (mPAN, mPANPH, and mPNAPH) with phenanthro[9,10‐d]imidazole (PI) and pyridinyl as donor and π‐bridge respectively. Changes in various kinds of polycyclic aromatic derivative acceptors (anthracene, 9‐phenylanthracene, and 1‐phenylnaphthalene) could manipulate the excited states and optoelectronic properties. Theoretical calculations reveal that the S1 state of mPNAPH exhibits HLCT nature while the other two molecules show local excited (LE) state dominated feature. The photophysical properties also demonstrate this characteristic. Therefore, compared with mPAN and mPANPH, mPNAPH has higher photoluminescence quantum yield (PLQY) whether in solutions or neat films. Ultimately, the non‐doped devices based on these emitters show high luminance larger than 35000 cd m−2, and high maximum external quantum efficiencies (EQEmaxs) larger than 5 % with low efficiency roll‐off. In particular, the mPNAPH‐based device displays an excellent performance of pure blue emission at 456 nm with Commission Internationale de L'Eclairage coordinate of (0.15, 0.16) and EQEmax of 6.13 % that benefited from the HLCT state and high‐lying reverse intersystem crossing process. [ABSTRACT FROM AUTHOR]

Triplet excitons in a high-lying reverse intersystem crossing (hRISC) process play an important role in realizing efficient deep-blue materials, and how to make full use of triplet excitons becomes a big challenge. Herein, three anthracene-based deep blue emitters were successfully synthesized, namely DCAT, DCAO and CNAT. Combined experimental tests and theoretical calculations reveal that all three molecules show multi-channel utilization of triplet excitons. Especially for DCAT, the large T1–T2 and small S1–T2 energy gaps, as well as the degenerate state of T2–T6, provide a fast and convenient channel for more triple exciton transitions from T2 → S1. Other conversion channels include T10 → S2 and T10 → S3, and multiple conversion channels together contribute to the high exciton utilization efficiency of DCAT of up to 60%. More importantly, by connecting large steric hindrance groups at the 9 and 10-positions of anthracene, π–π stacking was suppressed and deep-blue emission was achieved. As a result, deep-blue OLEDs based on DCAT exhibit an excellent maximum external quantum efficiency (EQEmax) of 6.8% with the Commission international de I'Eclairage (CIE) coordinates of (0.14, 0.07). These results fully demonstrate the importance of triplet excitons utilized through multi-channel pathways and provide insights into the development of high-performance deep-blue OLEDs. [ABSTRACT FROM AUTHOR]

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Abstract: A kind of macroscopic fiber of α-Zr(C6H5PO3)2 with diameter in millimeter scale and length in centimeter is synthesized by the method of infiltration–diffusion in this paper. Compared to the routine method [Q.H. Xu, L.S. Fu, L.S. Li, H.J. Zhang, R.R. Xu, J. Mater. Chem. 10 (2000) 2532], no HF was used in the synthesis and the SEM (scanning electronic microscopy) image indicates that these fibers have tubular structures which composed of flakes overlapped with each other vertically to the growth direction of the fiber. Powder X-ray diffraction (PXRD) proves that the walls of the tubes are composed of α-Zr(C6H5PO3)2 (α-ZrBP). As we know, it is the first report on synthesis of fiber-tube to α-ZrBP. [Copyright &y& Elsevier]

Chromophores with hybridized local and charge-transfer (HLCT) excited state are promising for the realization of high performance blue organic light-emitting diodes (OLEDs). The rational manipulation of HLCT excited state for efficient emitters remains challenging. Herein, we present three donor-π-acceptor (D-π-A) molecules (mPAN, mPANPH, and mPNAPH) with phenanthro[9,10-d]imidazole (PI) and pyridinyl as donor and π-bridge respectively. Changes in various kinds of polycyclic aromatic derivative acceptors (anthracene, 9-phenylanthracene, and 1-phenylnaphthalene) could manipulate the excited states and optoelectronic properties. Theoretical calculations reveal that the S 1 state of mPNAPH exhibits HLCT nature while the other two molecules show local excited (LE) state dominated feature. The photophysical properties also demonstrate this characteristic. Therefore, compared with mPAN and mPANPH, mPNAPH has higher photoluminescence quantum yield (PLQY) whether in solutions or neat films. Ultimately, the non-doped devices based on these emitters show high luminance larger than 35000 cd m -2 , and high maximum external quantum efficiencies (EQE max s) larger than 5 % with low efficiency roll-off. In particular, the mPNAPH-based device displays an excellent performance of pure blue emission at 456 nm with Commission Internationale de L'Eclairage coordinate of (0.15, 0.16) and EQE max of 6.13 % that benefited from the HLCT state and high-lying reverse intersystem crossing process., (© 2023 Wiley-VCH GmbH.)