Color-saturated green-emitting molecules with high Commission Internationale de L’Eclairage (CIE) y values have great potential applications for displays and imaging. Here, we linked the outer phenyl groups in multiple-resonance (MR)-type blue-emitting B (boron)-N (nitrogen) molecules through bonding and spiro-carbon bridges, resulting in rigid green emitters with thermally activated delayed fluorescence. The MR effect and multiple interlocking strategy greatly suppressed the high-frequency vibrations in the molecules, which emit green light with a full-width at half-maximum of 14 nm and a CIE y value of 0.77 in cyclohexane. These were the purest green molecules with quantum efficiency and color purity that were comparable with current best quantum dots. Doping these emitters into a traditional green-emitting phosphorescence organic light-emitting diode (OLED) endowed the device with a Broadcast Service Television 2020 color-gamut, 50% improved external quantum efficiency, and an extremely high luminescence of 5.1 × 105 cd/m2, making it the greenest and brightest OLED ever reported.

The existence and detection of leads are critical to obtain a local Sea Surface Height (SSH) reference for computing total freeboard and sea ice thickness from NASA's IceBridge Airborne Topographic Mapper (ATM) elevations. However, the shaded areas of the Digital Mapping System (DMS) images and the biased ATM elevations impact the correct determination of leads and SSH. This study develops an automated approach to overcome the above challenges and to correctly determine SSHs by combining DMS images, ATM L1B's apparent reflectivity and statistical discrimination. Dynamic pixel intensity thresholds are established to classify leads under different solar illuminations. This automated approach is then validated by manual selection in detecting SSHs. The high agreement of SSHs from this automated approach with those from manual selection indicates the reliability and usefulness of this approach. Within a 45-km section of one ATM L1B file, SSH demonstrates a linear gradient, which is applied to derive SSHs where there are no leads. The resulted SSHs are then used to compute total freeboard and ice thickness. This automated approach is also tried to retrieve SSH and then compute the total freeboard on one entire IceBridge sea ice flight each in Arctic and Antarctica.

Metal-free thermally activated delayed fluorescence (TADF) emitters have emerged as promising candidate materials for highly efficient and low-cost organic light-emitting diodes (OLEDs). Here, a novel acceptor 2-cyanopyrazine is selected for the construction of blue TADF molecules via computer-assisted molecular design. Both theoretical prediction and experimental photophysical data indicate a small S 1 -T 1 energy gap (Δ E ST ) and a relative large fluorescence rate ( k F ) in an o -phenylene-bridged 2-cyanopyrazine/3,6-di- tert -butylcarbazole compound (TCzPZCN). The k F value of 3.7 × 10 7 s −1 observed in a TCzPZCN doped film is among the highest in the TADF emitters with a Δ E ST smaller than 0.1 eV. Blue TADF emission is observed in a TCzPZCN doped film with a short TADF lifetime of 1.9 μs. The OLEDs using TCzPZCN as emitter exhibit a maximum external quantum efficiency (EQE) of 7.6% with low-efficiency roll-off. A sky-blue device containing a derivative of TCzPZCN achieves an improved EQE maximum of 12.2% by suppressing the non-radiative decay at T 1 .

Introducing two mesityl groups to the rigid and planar molecule dibenzo[2,3:5,6]pyrrolizino[1,7-bc]indolo[1,2,3-lm]carbazole successfully suppressed the aggregation-induced redshift and broadening in the emission spectra, enabling the new emitter mMes2DICz to be a...

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