摘要
Two electron-deficient azaacenes including di-and tetra-cyanodiazafluorene(DCAF and TCAF)with the advantages of deep lowest unoccupied molecular orbital(LUMO),green-synthesis,low-cost,simply purification method,excellent yields have been obtained,characterized and used as electron injection materials(EIMs)in three groups of electroluminescence devices.Device B with TCAF as EIM exhibited the best performance including turn-on voltage of 5.0 V,stronger maximum luminance intensity of 31,549 cd/m2,higher luminance efficiency of 62.34 cd/A and larger power efficiency of 21.74 lm/W which are 0.53,6.7,9.3 and 15.3 times than that of device A with DCAF as EIMs,respectively.The enhanced interfacial electron injection ability of TCAF than that of DCAF is supported by its better electron mobility in electron-only device,deeper LUMO(-4.52 eV),and stronger electronic affinity.Best external quantum efficiency of 16.56%was achieved with optimized thicknesses of TCAF as EIM and TPBi as electron transporting layer.As a new comer of acceptor family,TCAF would push forward organic electronics with more fascinating and significant applications.
Two electron-deficient azaacenes including di-and tetra-cyanodiazafluorene(DCAF and TCAF) with the advantages of deep lowest unoccupied molecular orbital(LUMO),green-synthesis,low-cost,simply purification method,excellent yields have been obtained,characterized and used as electron injection materials(EIMs) in three groups of electroluminescence devices.Device B with TCAF as EIM exhibited the best performance including turn-on voltage of 5.0 V,stronger maximum luminance intensity of31,549 cd/m^2,higher luminance efficiency of 62.34 cd/A and larger power efficiency of 21.74 lm/W which are 0.53,6.7,9.3 and 15.3 times than that of device A with DCAF as EIMs,respectively.The enhanced interfacial electron injection ability of TCAF than that of DCAF is supported by its better electron mobility in electron-only device,deeper LUMO(-4.52 eV),and stronger electronic affinity.Best external quantum efficiency of 16.56% was achieved with optimized thicknesses of TCAF as EIM and TPBi as electron transporting layer.As a new comer of acceptor family,TCAF would push forward organic electronics with more fascinating and significant applications.
基金
the National Natural Science Foundation of China(Nos.21975126,51673095,21875104,21875191,21603104)
the Natural Science Foundation of Jiangsu Province(Nos.BK20171470,BK20160991,BK20150064,BK20130912)
973 Program(No.2015CB932200)
Ministry of Education and Synergetic Innovation Center for Organic Electronics and Information Displays for financial support
