Organic light-emitting diodes (OLEDs) have outperformed conventional display technologies in smartphones, smartwatches, tablets, and televisions while gradually growing to cover a sizable fraction of the solid-state lighting industry. Blue emission is a crucial chromatic component for realizing high-quality red, green, blue, and yellow (RGBY) and RGB white display technologies and solid-state lighting sources. For consumer products with desirable lifetimes and efficiency, deep blue emissions with much higher power efficiency and operation time are necessary prerequisites. This article reviews over 700 papers covering various factors, namely, the crucial role of blue emission for full-color displays and solid-state lighting, the performance status of blue OLEDs, and the systematic development of fluorescent, phosphorescent, and thermally activated delayed fluorescence blue emitters. In addition, various challenges concerning deep blue efficiency, lifetime, and approaches to realizing deeper blue emission and higher efficacy for blue OLED devices are also described.

Resistive switching devices are promising candidates for the next generation of nonvolatile memory and neuromorphic computing applications. Despite the advantages in retention and on/off ratio, filamentary-based memristors still suffer from challenges, particularly endurance (flash being a benchmark system showing 10 ⁴ to 10 ⁶ cycles) and uniformity. Here, we use WO ₃ as a complementary metal-oxide semiconductor–compatible switching oxide and demonstrate a proof-of-concept materials design approach to enhance endurance and device-to-device uniformity in WO ₃ -based memristive devices while preserving other performance metrics. These devices show stable resistive switching behavior with >10 ⁶ cycles, >10 ⁵ -second retention, >10 on/off ratio, and good device-to-device uniformity, without using current compliance. All these metrics are achieved using a one-step pulsed laser deposition process to create self-assembled nanocomposite thin films that have regular guided filaments of ≈100-nanometer pitch, preformed between WO ₃ grains and interspersed smaller Ce ₂ O ₃ grains.

Low color temperature candlelight organic light-emitting diodes (LEDs) are human and environmentally friendly because of the absence of blue emission that might suppress at night the secretion of melatonin and damage retina upon long exposure. Herein, we demonstrated a lighting device incorporating a phenoxazine-based host material, 3,3-bis(phenoxazin-10-ylmethyl)oxetane (BPMO), with the use of orange-red and yellow phosphorescent dyes to mimic candlelight. The resultant BPMO-based simple structured candlelight organic LED device permitted a maximum exposure limit of 57,700 s, much longer than did a candle (2750 s) or an incandescent bulb (1100 s) at 100 lx. The resulting device showed a color temperature of 1690 K, which is significantly much lower than that of oil lamps (1800 K), candles (1900 K), or incandescent bulbs (2500 K). The device showed a melatonin suppression sensitivity of 1.33%, upon exposure for 1.5 h at night, which is 66% and 88% less than the candle and incandescent bulb, respectively. Its maximum power efficacy is 23.1 lm/W, current efficacy 22.4 cd/A, and external quantum efficiency 10.2%, all much higher than the CBP-based devices. These results encourage a scalable synthesis of novel host materials to design and manufacture high-efficiency candlelight organic LEDs.

In this report, Bovine Serum Albumin-based Metal–Insulator–Metal structures on Indium doped Tin Oxide coated flexible Polyethylene Terephthalate substrates with Aluminum (Al) as the top electrode have been fabricated and studied in detail. The thickness of the film was measured using a Field Emission Scanning Electron Microscope. The Fourier Transform Infrared Attenuated Total Reflectance spectrum confirms the presence of both amide-I and amide-II in the protein film. Ultraviolet-Visible Spectroscopy was performed for the absorption spectrum used to extract the optical bandgap. The surface roughness of the film was estimated by Atomic Force Microscopy. Electrical characterization of the devices gives a high capacitance density with a negative quadratic coefficient and a low dissipation factor, showing their potential for Radio Frequency/analog application. The number of dipoles (N_PD) is found to be 1.01 × 10¹⁸ cm⁻³ with a permanent dipole moment (μ₀) of 2.92 × 10⁻²⁵ C m at an applied frequency of 1 MHz. The devices show high reliability resistant to degradation, studied by Constant Voltage Stressing. We also examined the performance of these flexible devices by repeated bending with different bending radii.

Y ₃ Fe ₅ O ₁₂ (YIG)–Au nanocomposites showed improved magnetic damping over pure YIG films while also introducing new hyperbolic optical properties.