New perylene diimide derivatives: stable red emission, adjustable property from ACQ to AIE, and good device performance with an EQE value of 4.93

Perylene diimide (PDI) derivatives, due to their special opto-electronic property, have been successfully utilized in organic field-effect transistor (OFET), solar cells, and as non-fullerene acceptor and others, while few cases in organic light-emitting diodes (OLEDs). In this work, six perylene bisimide-based red emitters, N,N'-bis(2-decyltetradecyl)-1-([1,1':3',1″-terphenyl]-5'-yl)perylene-3,4,9,10-diimide (STPH), N,N'-bis(2-decyltetradecyl)-1,7-bis([1,1':3',1″-terphenyl]-5'-yl)perylene-3,4,9,10-diimide (DTPH), N,N'-bis(2-decyltetradecyl)-1-(5'-phenyl-[1,1':3',1″-terphenyl]-4-yl)perylene-3,4,9,10-diimide (STRPH), N,N'-bis(2-decyltetradecyl)-1,7-bis(5'-phenyl-[1,1':3',1″-terphenyl]-4-yl)perylene-3,4,9,10-diimide (DTRPH), N,N'-bis(2-decyltetradecyl)-1-(4-(2,2-diphenylvinyl)phenyl)perylene-3,4,9,10-diimide (STTPE) and N,N'-bis(2-decyltetradecyl)-1,7-bis(4-(2,2-diphenylvinyl)phenyl)perylene-3,4,9,10-diimide (DTTPE), with the excellent chemical, thermal and photo-chemical stability, are synthesized through the convenient Suzuki coupling reaction, in which, the fluorescent properties can be modified easily from ACQ to AIE by just simply changing the bulky volume of the introduced aromatic substituents. After being fabricated into organic light-emitting diodes, STRPH exhibits the best performance with the maximum luminescence, power efficiency, current efficiency and external quantum efficiency of 1,948 cd m^-2, 2.04 lm W^-1, 5.85 cd A^-1, 4.93% at Commission Internationale de L'Eclairage (CIE) coordinates of (0.56, 0.34), as the result of the high efficient energy transfer and good energy match achieved in the device.

A diphenylamino-substituted quinacridone derivative: red fluorescence based on intramolecular charge-transfer transition

A red emissive quinacridone derivative has been prepared through construction of an ICT system. This resulted in the first efficient and bright red OLED based on a quinacridone derivative.

Quantum yield in blue-emitting anthracene derivatives: vibronic coupling density and transition dipole moment density

Diagonal vibronic couplings in the Franck–Condon S₁ state cause torsional distortion, which gives rise to enhancement of fluorescence with a large transition dipole moment.

Dicyanomethylene-4H-pyran chromophores for OLED emitters, logic gates and optical chemosensors

Dicyanomethylene-4H-pyran (DCM) chromophores are typical donor-π-acceptor (D-π-A) type chromophores with a broad absorption band resulting from an ultra-fast internal charge-transfer (ICT) process. In 1989, Tang et al. firstly introduced a DCM derivative as a highly fluorescent dopant in organic electroluminescent diodes (OLEDs). Integration of ICT chromophore-receptor systems based on DCM chromophores with ion-induced shifts in absorption or emission is a convenient method to perform the logic expression for molecular logic gates. In recent years, various DCM-type derivatives have been explored due to their excellent optical-electronic properties and diverse structural modification. This feature article provides an insight into how the structural modification of DCM chromophores can be utilized for OLED emitters, logic gates and optical chemosensors. In addition, the aggregation-induced-emission (AIE) of DCM derivatives for further optical applications was also introduced.

Thermally stable, dye-bridged nanohybrid-based white light-emitting diodes

Thermally stable red and green light-emitting nanohybrids are introduced as an organic luminescent converter with broad color tunability and a high color rendering index for white light-emitting diodes (LEDs). Nanohybrid-based white LEDs are thermally stable and the color coordination is not changed by heat exposure.

Proton-induced fluorescent switching of a new 2D-pi-A type vinylcyanoacetate-pyran dye

A new 2D-pi-A type vinylcyanoacetate-pyran dye, ethyl 2-(2,6-bis(2-butoxy-4-(diethylamino)styryl)-4H-pyran-4-ylidene)-2-cyanoacetate (BDPC) was prepared by condensation reaction. The chemical structures of all the intermediates and the BDPC dye are characterized by (1)H NMR, MS. It showed interestingly solvatochromic and solvatofluorchromic properties in various solvents. Its LUMO and HOMO values were obtained by the theoretical calculation. The fluorescent intensity of BDPC dye can be reversibly selected by protonation/deprotonation of the amine moiety via control of intramolecular charge transfer (ICT), leading to a fluorescent molecular switch with two distinguished "on" and "off" states.