Research on multi-color OLED with bi-directional charge transfer using Ag: Mg as intermediate electrode

Abstract

Organic light-emitting devices (OLEDs) have received widespread attention due to their excellent luminescence performance and flexibility. In this work, we demonstrate a novel two-color OLED, in which the forward and reverse units are vertically stacked together using Ag: Mg as an intermediate electrode for charge injection and transfer. Due to the extremely thin Ag: Mg film layer has a relatively smooth surface, it plays a critical role in the reverse unit light emission of the device. Thus, it is realized that the device emits green and red light when forward and reverse voltages are applied respectively. This provides a new possibility for future OLEDs lighting and display developments. The OLEDs were prepared by using such Ag: Mg intermediate electrodes, and a maximum brightness of 451.14 cd/m² and an external quantum efficiency (EQE) of 3.82% were obtained at a small current density.

References

[1] KidoJ, HongawaK, OkuyamaK, et al.. White light-emitting organic electroluminescent devices using the poly(N-vinylcarbazole) emitter layer doped with three fluorescent dyes[J]. Applied physics letters, 1994, 64(7):815

[2] TangC W, VanslykeS A. Organic electroluminescent diodes[J]. Applied physics letters, 1987, 51(12): 913

[3] D’AndradeB W, ForrestS R. White organic light-emitting devices for solid-state lighting[J]. Advanced materials, 2004, 16: 1585-1595

[4] JeffreyP, SpindlerT K, HatwarM E, et al.. System considerations for RGBW OLED displays[J]. Journal of the SID, 2006, 14(1):37

[5] Journal of the SID, 2010, 18(9):

[6] MalteC G, AnneK, KlausM. White organic light-emitting diodes[J]. Advanced materials, 2011, 23: 233-248

[7] XieJ H, YaoJ W, DaiY F, et al.. Improvement of exciton utilization by suppressing exciton leakage for high efficiency blue and white organic light-emitting diodes[J]. Journal of materials chemistry C, 2022, 10: 8349-8355

[8] DongB Z, YanJ K, LiG Z, et al.. High luminance/efficiency monochrome and white organic light emitting diodes based pure exciplex emission[J]. Organic electronics, 2022, 106: 106528

[9] LeungM Y, TangM C, CheungW L, et al.. Thermally stimulated delayed phosphorescence (TSDP)-based gold(III) complexes of tridentate pyrazine-containing pincer ligand with wide emission color tunability and their application in organic light-emitting devices[J]. Journal of the American Chemical Society, 2020, 142(5):2448-2459

[10] WangQ, BaiJ W, SunQ. Simplified dopant-free color-tunable organic light-emitting diodes[J]. Applied physics letters, 2021, 118: 253301

[11] YingS A, WuY B, DaiY F, et al.. High efficiency color-tunable organic light-emitting diodes with ultra-thin emissive layers in blue phosphor doped exciplex[J]. Applied physics letters, 2019, 114: 033501

[12] EnriqueP G, PercinoM J, WilsonB, et al.. Fluorescence tuning with a single dye embedded in a polymer matrix and its application on multicolor OLEDs[J]. Dyes and pigments, 2020, 186: 108979

[13] MaoM, LamT L, ToW P, et al.. Stable, high-efficiency voltage-dependent color-tunable organic light-emitting diodes with a single tetradentate platinum(II) emitter having long operational lifetime[J]. Advanced materials, 2020, 33(2):2004873

[14] WallaceC H C, NiuJ H, ChenX W, et al.. Effects of carrier barrier on voltage controllable color tunable OLEDs[J]. Applied physics A, 2007, 89: 667-671

[15] JangJ G, KimH, KimJ M. Two color realization of red and blue by the selective deposition of a red light emitter[J]. Molecular crystals and liquid crystals, 2013, 584(1):44-52

[16] JiangY B, LianJ R, ChenS M, et al.. Fabrication of color tunable organic light-emitting diodes by an alignment free mask patterning method[J]. Organic electronics, 2013, 14: 2001-2006

[17] SunN, JiangC M, TanD C, et al.. A color-tunable and high-effective organic light-emitting diode device with forward-inverse structure as intelligent lighting display[J]. Journal of materials science-materials in electronics, 2021, 32: 22309-22318

[18] BurrowsP E, ForrestS R, SibleyS P, et al.. Color-tunable organic light-emitting devices[J]. Applied physics letters, 1996, 69: 2959

[19] ForrestS R, BurrowsP E, ShenZ, et al.. The stacked OLED (SOLED): a new type of organic device for achieving high-resolution full-color displays[J]. Synthetic metals, 1997, 91: 9-13

[20] FriesF, FröbelM, LenkS, et al.. Transparent and color-tunable organic light-emitting diodes with highly balanced emission to both sides[J]. Organic electronics, 2017, 41: 315-318

[21] LeeH, ChoH, ByunC W, et al.. Color-tunable organic light-emitting diodes with vertically stacked blue, green, and red colors for lighting and display applications[J]. Optics express, 2018, 26(14):18351

[22] GuoF, KarlA, XueQ F, et al.. The fabrication of color-tunable organic light-emitting diode displays via solution processing[J]. Light: science & applications, 2017, 6(11): e17094

[23] JeonY M, NohI, SeoY C, et al.. Parallel-stacked flexible organic light-emitting diodes for wearable photodynamic therapeutics and color-tunable optoelectronics[J]. ACS nano, 2020, 14(11): 15688-15699

[24] GuG, ParthasarathyG, TianP, et al.. Transparent stacked organic light emitting devices. II. Device performance and applications to displays[J]. Journal of applied physics, 1999, 86: 4076-4084

[25] SeongK K, RajuL, JangH K. Electro-optically efficient and thermally stable multilayer semitransparent pristine Ag cathode structure for top-emission organic light-emitting diodes[J]. ACS photonics, 2019, 6: 2957-2965