A tandem white organic light emitting device

Abstract

The invention relates to a white organic light-emitting device in series, which includes a substrate, and a first electrode layer, a plurality of blue fluorescent light-emitting units, a plurality of charge generation layers, a plurality of phosphorescent light-emitting units and a second electrode layer are stacked, and the adjacent blue fluorescent light-emitting units An n-type charge generation layer made of an n-type material is arranged between the phosphorescent light-emitting unit; the phosphorescent light-emitting unit includes a first hole transport layer, a phosphorescent light-emitting layer and a first electron transport layer; the first hole The transport layer includes a first hole material layer, a transition layer and a second hole material layer; the first hole material layer is in contact with the n-type charge generation layer; the first hole material layer and the n-type The charge generation layers collectively constitute the charge generation layer. Since the material of the first hole transport layer is evaporated by a linear evaporation source to form a continuous concentration gradient structure, the number of evaporation sources in the evaporation chamber is reduced, and the hole injection barrier is greatly reduced, thereby significantly reducing the voltage of the device and improving efficiency.

Description

technical field [0001] The invention relates to the technical field of serial white organic light-emitting devices, in particular to a material for a hole transport layer of a phosphorescent light-emitting unit that is vapor-deposited by a linear evaporation source to form a continuous structure with a concentration gradient. Background technique [0002] A tandem white organic light emitting device includes a charge generation layer sandwiched between two light emitting units. The charge generation layer transports electrons or holes to adjacent light emitting units. However, in the tandem white organic light emitting device, holes or electrons of the charge generation layer may not be transported to adjacent light emitting units. In this case, normal light emission may not be performed in the adjacent phosphorescent light emitting unit or fluorescent light emitting unit. In order to overcome such problems, a hole transport layer having a double-layer structure (including...

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Problems solved by technology

[0004] Therefore, the technical problem to be solved by the present invention lies in the problem of high voltage and difficult preparation in the prior art, and further provides a series white organic light-emitting device, since the first hole transport layer is evaporated by a linear evaporation source to form a continuous concentration gradient structure, reducing the number of evaporation sources in the evaporation chamber, greatly reducing the hole injection barrier, which can significantly reduce the voltage of the device and improve efficiency

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