As an intermolecular excited states with separated HOMO and LUMO, exciplex for OLED is gradually taking a contribution in thermally activated delayed fluorescence (TADF) device due to their advantages in...

High performance Alq3-based organic light emitting diodes are achieved by using magnetic nanoparticles/poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) as the composite hole-injection layer through the advantageous combination of light-scattering, localized surface plasmon resonance and magnetic effect.

Polymeric carbon nitride (CNxHy) has been facilely synthesized from dicyandiamide and functions as a solution-processed hole injection layer in organic light-emitting diodes (OLEDs). The measurements using X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and impedance spectroscopy elucidate that CNxHy exhibits superior film morphology and extra electric properties such as tailored work function and tunable hole injection. The luminous efficiency of CNxHy-based OLED is found to improve by 76.6% in comparison to the counterpart using favorite solution-processed poly(ethylene dioxythiophene):poly(styrene sulfonate) as the hole injection layer. Our results also pave a way for broadening carbon nitride applications in organic electronics using the solution process.

Colloidal semiconductor CdSe nanoplatelets (NPLs) feature ultranarrow and anisotropic emissions. However, the optical performance of blue‐emitting NPLs is deteriorated by trap states, currently exhibiting tainted emissions and inferior photoluminescence quantum yields (PLQYs). Here, near trap‐free blue‐emitting NPLs are achieved by the controlled growth of the core/crown. Deep trap states in NPLs can be partially suppressed with the asymmetrical crown growth and are further suppressed with the growth of the small core and the alloyed symmetrical crown, yielding NPLs with pure blue emissions and near‐unity PLQYs. Exciton dynamic research based on these NPLs indicates that the trap emission stems from surface traps. Besides, light‐emitting diodes exhibiting ultranarrow emission centered around 461 nm with full‐width‐at‐half‐maximums down to 11 nm are fabricated using these NPLs.

Colloidal II–VI group nanoplatelets (NPLs) possess ultranarrow emission line widths, for which they have great promise in achieving the purest display color in solution-processed light-emitting diodes (LEDs). Red NPL-LEDs have shown extremely saturated red color with high efficiency, while the green and blue ones lag far behind. Herein, we report green NPL-LEDs with the purest color in accordance with the Rec. 2020 standard and the peak external quantum efficiency (EQE) of 9.78%. By carefully controlling the aspect ratio, capping ligands, and purifications of CdSe/CdSeS core/alloyed-crown NPLs, NPL films with excellent flatness and unity photoluminescence quantum yields (PLQYs) are realized, laying a solid foundation for improving LED performance. Furthermore, via tuning the carrier injection balance, the record-high EQE for green NPL-LEDs is achieved. The electroluminescence (EL) exhibits an extremely saturated green color with the Commission Internationale de L’Eclairage (CIE) coordinates of (0.163 0.786), which demonstrates their great potential in applications of ultrahigh-definition display technology. Our findings would help to further improve the performance of all NPL-LEDs.