Jayabharathi Jayaraman, Panimozhi Sekar, Thanikachalam Venugopal
Department of Chemistry, Annamalai University, Annamalai nagar, 608 002, Tamilnadu, India.
Sci Rep. 2019 Nov 26;9(1):17555. doi: 10.1038/s41598-019-54125-x.
The electroluminescent properties of asymmetrically twisted phenanthrimidazole derivatives comprised of fluorescent anthracene or pyrene unit namely, 1-(1-(anthracen-10-yl)naphthalen-4-yl)-2-styryl-1H-phenanthro[9,10-d]imidazole (ANSPI), 1-(1-(pyren-1-yl) naphthalene-4-yl)-2-styryl-1H-phenanthro[9,10-d]imidazole (PNSPI), 4-(2-(4-(anthracen-9-yl) styryl)-1H-phenanthro[9,10-d]imidazol-1-yl)naphthalene-1-carbonitrile (ASPINC) and 4-(2-(4-(pyren-1-yl)styryl)-1H-phenanthro[9,10-d]imidazol-1-yl)naphthalene-1-carbonitrile (PSPINC) for blue OLEDs have been analyzed. The asymmetrically twisted conformation interrupt π-conjugation effectively results in deep-blue emission. The pyrene containing PSPINC based non-doped blue device (476 nm) shows maximium efficiencies (current efficiency (η)-4.23 cd/A; power efficiency (η)-2.86 lm/W; external quantum efficiency (η-3.48%: CIE (0.16, 0.17) at 3.10 V. Among the doped blue devices, An(PPI):ASPINC shows high efficiencies (η-12.13 cd/A; η-5.98 lm/W; η-6.79%; L-23986 cd m; EL-458 nm) at 3.15 V with CIE (0.15, 0.17) than An(PPI):PSPINC based device which is inconsistent with non-doped device performances. The green and red PhOLEDs show higher efficiencies with Ir(ppy): ASPINC (η-50.6 cd/A; η-53.4 lm/W; η-17.0%; L-61581 cd m; EL-501 nm, CIE (0.31, 0.60) at 3.32 V and (bt)Ir(dipba): ASPINC (η-15.2 cd/A; η-16.5 lm/W; η-14.5%; L-13456 cd m; EL-610 nm), CIE (0.63, 0.36) at 3.20 V, respectively. The complete energy transfer between the host and dopant molecules improved the efficiency of PHOLEDs.
已对由荧光蒽或芘单元组成的不对称扭曲菲并咪唑衍生物的电致发光特性进行了分析，这些衍生物包括1-(1-(蒽-10-基)萘-4-基)-2-苯乙烯基-1H-菲并[9,10-d]咪唑(ANSPI)、1-(1-(芘-1-基)萘-4-基)-2-苯乙烯基-1H-菲并[9,10-d]咪唑(PNSPI)、4-(2-(4-(蒽-9-基)苯乙烯基)-1H-菲并[9,10-d]咪唑-1-基)萘-1-甲腈(ASPINC)和4-(2-(4-(芘-1-基)苯乙烯基)-1H-菲并[9,10-d]咪唑-1-基)萘-1-甲腈(PSPINC)，用于蓝色有机发光二极管。不对称扭曲构象有效地中断了π共轭，导致深蓝色发射。基于芘的PSPINC非掺杂蓝色器件(476nm)显示出最高效率(电流效率(η)-4.23cd/A；功率效率(η)-2.86lm/W；外量子效率(η)-3.48%；在3.10V时CIE(0.16,0.17))。在掺杂蓝色器件中，An(PPI):ASPINC在3.15V时显示出高效率(η-12.13cd/A；η-5.98lm/W；η-6.79%；L-23986cd m；EL-458nm)，CIE(0.15,0.17)，比基于An(PPI):PSPINC的器件更高，这与非掺杂器件的性能不一致。绿色和红色磷光有机发光二极管与Ir(ppy):ASPINC(η-50.6cd/A；η-53.4lm/W；η-17.0%；L-61581cd m；EL-501nm，在3.32V时CIE(0.31,0.60))和(bt)Ir(dipba):ASPINC(η-15.2cd/A；η-16.5lm/W；η-14.5%；L-13456cd m；EL-610nm)，在3.20V时CIE(0.63,0.36))分别显示出更高的效率。主体和掺杂剂分子之间的完全能量转移提高了磷光有机发光二极管的效率。
