High-efficiency/CRI/color stability warm white organic light-emitting diodes by incorporating ultrathin phosphorescence layers in a blue fluorescence layer

Abstract

By incorporating ultrathin (<0.1 nm) green, yellow, and red phosphorescence layers with different sequence arrangements in a blue fluorescence layer, four unique and simplified fluorescence/phosphorescence (F/P) hybrid, white organic light-emitting diodes (WOLEDs) were obtained. All four devices realize good warm white light emission, with high color rending index (CRI) of >80, low correlated color temperature of <3600 K, and high color stability at a wide voltage range of 5 V-9 V. These hybrid WOLEDs also reveal high forward-viewing external quantum efficiencies (EQE) of 17.82%-19.34%, which are close to the theoretical value of 20%, indicating an almost complete exciton harvesting. In addition, the electroluminescence spectra of the hybrid WOLEDs can be easily improved by only changing the incorporating sequence of the ultrathin phosphorescence layers without device efficiency loss. For example, the hybrid WOLED with an incorporation sequence of ultrathin red/yellow/ green phosphorescence layers exhibits an ultra-high CRI of 96 and a high EQE of 19.34%. To the best of our knowledge, this is the first WOLED with good tradeoff among device efficiency, CRI, and color stability. The introduction of ultrathin (<0.1 nm) phosphorescence layers can also greatly reduce the consumption of phosphorescent emitters as well as simplify device structures and fabrication process, thus leading to low cost. Such a finding is very meaningful for the potential commercialization of hybrid WOLEDs.

Designing Highly Efficient Phosphorescent Neutral Tetrahedral Manganese(II) Complexes for Organic Light‐Emitting Diodes

“…Phosphorescent transition‐metal complexes have played the vital role in the rapid development of OLEDs, because they can harvest both singlet and triplet excitons to achieve an internal quantum efficiency of 100% owing to the highly efficient spin‐orbit coupling effect induced by heavy‐metal atoms . For example, noble metal‐based phosphors including iridium(III) complexes, platinum(II) complexes, and gold(III) complexes have been widely used in phosphorescent OLEDs (PhOLEDs). However, these noble metals suffer from the low abundance and high cost.…”

Synthesis and properties of hyperbranched polymers for white polymer light-emitting diodes

“…In these devise, ITO and Al are used as anode and cathode, respectively; PEDOT:PSS and TPBi are used as hole transport layer and electron transport layer, respectively; 50 nmthick polymers layer is used as EML, and 1 nm-thick LiF layer used as electron injection layer. 1,[31][32][33][34][35] Fig . 6a-d shows the EL spectra for all polymers-based PLEDs at voltages varying from 7 to 11 V. It can be seen that all resulting PLEDs with PFCzSDF10Ir6, PFCzSDF10Ir7, PFCzSDF10Ir8, PFCzSDF10Ir9 as realize good white emission with CIE coordinate of at (0.27,0.25), (0.27,0.24), (0.26,0.30), and (0.27,0.31) at 11 V, respectively, and the EL spectra for these PLEDs all contain two main emission peaks located at blue and orange-red wavebands, which are corresponding to the emissions of poly(uorene-altcarbazole) branches and red dimming phosphor group (Ir(piq) 2acac).…”

Conductive polyurethane elastomer electrolyte (PUEE) materials for anodic bonding

“…[1][2][3][4][5][6][7] Generally, the structure of a exible device includes a exible substrate, exible electrodes, functional materials and the sealing layer. [8][9][10][11][12] To achieve highperformance exible devices, except for the new organic electronic materials, advanced preparation and packaging techniques need to be comprehensively explored. Investigations have shown that packaging quality, one of the key indices of device preparation, directly determines the photoelectric performance, stability and lifetime of the product.…”