Organic Light Emitting Diodes (OLEDs) provide various attractive features for next generation illumination systems,
including high efficiency, low power, thin and flexible form factor. In this work, we incorporated phosphorescent
emitters and demonstrated highly efficient white phosphorescent OLED (PHOLED) devices on flexible plastic
substrates. The 0.94 cm2 small-area device has total thickness of approximately 0.25 mm and achieved 63 lm/W at 1,000
cd/m2 with CRI = 85 and CCT = 2920 K. We further designed and fabricated a 15 cm x 15 cm large-area flexible white
OLED lighting panels, finished with a hybrid single-layer ultra-low permeability single layer barrier (SLB)
encapsulation film. The flexible panel has an active area of 116.4 cm2, and achieved a power efficacy of 47 lm/W at
1,000 cd/m2 with CRI = 83 and CCT = 3470 K. The efficacy of the panel at 3,000 cd/m2 is 43 lm/W. The large-area
flexible PHOLED lighting panel is to bring out enormous possibilities to the future general lighting applications.
We report data for a pair of singlestack all-phosphorescent 15×15 cm2 organic light emitting-diode (OLED) light panels with high efficacy, long lifetime, and very low operating temperature: Panel 1 has 62 lm/W efficacy, CRI = 81 and lifetime to LT70 = 18,000 h at 1000 cd/m2, while Panel 2 has 58 lm/W efficacy, CRI = 82 and lifetime to LT70 = 30,000 h at 1000 cd/m2. Operating at a higher luminance of 3000 cd/m2, Panel 2 has 49 lm/W efficacy with lifetime to LT70 = 4000 h. Excellent panel lifetime is enabled by a stable light blue phosphorescent materials system. Panel temperatures are within 10°C of ambient temperature at 3000 cd/m2. Panel 2 was further used as a building block to demonstrate an all-phosphorescent OLED luminaire for under-cabinet lighting applications. Operating at approximately 3000 cd/m2, the luminaire delivers 570 lm with 52 lm/W total system efficacy, CRI = 86 and CCT = 2940 K.
Significant progress has been made in recent years in flexible AMOLED displays and numerous prototypes have been
demonstrated. Replacing rigid glass with flexible substrates and thin-film encapsulation makes displays thinner, lighter,
and non-breakable - all attractive features for portable applications. Flexible AMOLEDs equipped with phosphorescent
OLEDs are considered one of the best candidates for low-power, rugged, full-color video applications. Recently, we
have demonstrated a portable communication display device, built upon a full-color 4.3-inch HVGA foil display with a
resolution of 134 dpi using an all-phosphorescent OLED frontplane. The prototype is shaped into a thin and rugged
housing that will fit over a user's wrist, providing situational awareness and enabling the wearer to see real-time video
and graphics information.
Crystalline semiconductor nanomembranes (NMs), which are transferable, stackable, bondable and
manufacturable, offer unprecedented opportunities for unique and novel device applications. We report here
nanophotonic devices based on stacked semiconductor NMs on Si, glass and flexible PET substrates. Photonic
crystal Fano resonance-based surface-normal optical filters and broadband reflectors have been demonstrated with
unique angle and polarization properties. Flexible photodetectors and solar cells have also been developed based on
the NM stacking processes. Such NM stacking process can lead to a paradigm shift on silicon photonic integration
and inorganic flexible photonics.
We report theoretical and experimental investigations of infrared absorption characteristics for PbSe colloidal
quantum dots in defect-free photonic crystal (PC) cavities, via Fano resonances. Angle and polarization independent
transmission and absorption are feasible for surface normal incident beams with dispersion engineered modal
design. Experimental demonstration was done on patterned single crystalline silicon nanomembranes (SiNMs)
transferred on glass and on flexible PET substrates, with PbSe QDs backfilled into the air holes of the patterned
SiNMs. These findings enable the design of spectrally selective photodetectors at near infrared regime with the
desired angle and polarization properties.
We here proposed a new kind of ultra-compact filters based on Fano resonances on patterned single crystalline silicon
nanomembranes (SiNM), which were fabricated and transferred onto transparent substrates like PET plastic and glass
substrates, using a wet transfer process. The angular and polarization dependent transmission characteristics of the filter
are experimentally investigated. The filter transmission characteristics are insensitive to the incident angle and
polarization for surface-normal incidence. For other incident angle conditions, the transmission peaks/dips shift,
according to the modal dispersion properties, as verified with the simulated modal dispersion curves. Both surface-normal
and angle-dependent filter transmission measurement results agree well with the numerical simulations.