Color-stable, efficient fluorescent pure-white organic light-emitting diodes with device architecture preventing excessive exciton formation on guest

Abstract

Color-stable, high-efficiency fluorescent pure-white organic light-emitting diodes were fabricated using an electroluminescence-efficient blue host 2-(N,N-diphenylamino)-6-[4-(N,N-diphenylamino)styryl]naphthalene and yellow 5,6,11,12–tetra-phenylnaphthacene in a single emissive layer. The resultant power efficiency, at 100cd∕m2, for example, was 9.5lm∕W, and its emission changed from (0.321, 0.357) to (0.315, 0.344) for brightness increasing from 100to10000cd∕m2. The high color stability may be attributed to the device structure enabling the generation of excitons on host so that lesser excitons would form on guest, preventing exciton-quenching-caused blueshift.

Sunlight-like organic LED brings natural illumination indoors

“…To fabricate such OLEDs, we applied principles opposite to those for making color-stable OLEDs. 5,6 We found that the emissive color could be changed by varying the applied voltage. However, the color soon deviated from the daylight locus, and we observed only a very limited CT span.…”

P‐199L: Late‐News Poster: High‐Efficiency Low Color Temperature White OLEDs with Solution‐Processed Emissive Layer

“…Meanwhile, lesser excitons formed on guest would also prevent an undesired excessive excitons from causing quenching phenomenon which would result in low device efficiency. [13][14] Table I summarizes the effect of the doping concentrations of the guests on the device characteristics. As seen, these white devices showed daylight-like color with color-temperature as low as those of sunrise (3,000~3,500 K) or sunset (2,500~3,000 K).…”

Enabling high-efficiency organic light-emitting diodes with a cross-linkable electron confining hole transporting material

“…However, wet-processed devices often show comparatively poor performance 38 due to the lack of solution-process feasible functional materials that exhibit robust mechanical proper- 39 ties. We demonstrate here a cross-linkable material, 3,6-bis(4-vinylphenyl)-9-ethylcarbazole (VPEC), to 40 facilitate the injection of hole and meanwhile effectively confine electron to realize, for examples, high 41 efficiency organic light-emitting diodes, especially at high luminance.…”

“…66 Over the past years, numerous efficiency effective architectural 67 approaches have been proposed. They include the employment 68 of low interfacial resistance P-I-N structures [14-18], low 69 carrier-injection-barriers [19][20][21][22], balanced carrier injection 70 [23-28], carrier and exciton confinement [29][30][31][32][33], stepwise emis- 71 sive layers [34], carrier modulation layers [35][36][37], structures 72 enabling exciton to generate on host or on both host and guest 73 [38], structures facilitating host-to-guest energy transfer [39,40], 74 and co-host structures [41,42], etc. All these approaches are valid 75 for OLED devices fabricated via dry-process, but not all applicable 76 if via wet-process.…”