Synthesis, characterization and photo physical properties of two novel n-type semiconductor materials with trifluoromethyl and cyano groups

Zig‐Zag Type Molecular Design Strategy of N‐Type Hosts for Sky‐Blue Thermally‐Activated Delayed Fluorescence Organic Light‐Emitting Diodes

“…Electron transport can be plausible through dibenzofuran and the CN-modified biphenyl backbone with electron accepting ability. [21][22][23][24][25] It is expected that the management of the substitution position and interconnectionp ositionm ay control the carrier transport properties and energy levels of the hosts. The molecular design for electron transport properties was confirmed by picturing the highest-occupied molecular orbital (HOMO)a nd lowest-unoccupied molecular orbital (LUMO), based on frontier molecular orbital calculations using the B3LYP 6-31G* basis set in the Gaussian software.…”

“…High triplet energy can be obtained through large dihedral angle, by connecting dibenzofuran to the biphenyl backbone structure at the ortho position of the molecule. Electron transport can be plausible through dibenzofuran and the CN‐modified biphenyl backbone with electron accepting ability . It is expected that the management of the substitution position and interconnection position may control the carrier transport properties and energy levels of the hosts.…”

“…Thus, the exciton formation is dominated by the host, and various kinds of hosts have been used. Among the many host types, bipolar hosts and mixed hosts have been popular because of balanced carrier transport and wide recombination zone for high external quantum efficiency (EQE) and long lifetime . In particular, the mixed host has been proven to be effective to upgrade the device performances.…”

“…Thus, the exciton formation is dominated by the host, and variousk inds of hosts have been used.A mong the many hostt ypes,b ipolar hosts and mixedh osts have been popularb ecause of balancedc arrier transporta nd wider ecombination zone for high external quantum efficiency( EQE) andl ong lifetime. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] In particular, the mixed host has been provent ob ee ffective to upgrade the device performances. However,i nt he case of deep blue OLEDs, it has been challenging to develop mixed hosts because of difficulty of the design of high triplet energye lectron transport( n-type) host for phosphors or TADF emitters.…”

“…Electron transport can be plausible through dibenzofuran and the CN-modified biphenyl backbone with electron accepting ability. [21][22][23][24][25] It is expected that the management of the substitution position and interconnectionp ositionm ay control the carrier transport properties and energy levels of the hosts.…”