| Summary: | 碩士 === 輔仁大學 === 化學系 === 96 === In this experiment,we present and analyze the device performance of mixed layer organic light-emitting devices(OLEDs). The mixed layer material in this device consists of emitting layer(EML) coevaporated with electron transport layer(ETL) and hole transport layer(HTL),respectively.
We coevaporate the hole transport material TPD and emitting material DPVBi and use it as the EML. This mixed layer structure blurs the HTL/EML interface. The blurred interface reduce the carrier accumulation and reduce driving voltage,but adjust luminous mechanism. In order to prevent exciton forming in TPBi, we use BCP as hole blocking layer. Therefore,it keep emission wavelength of DPVBi and improve device luminous performance. the max luminance is 12519.43 cd/m2. The luminous power efficiency is 1.71 cd/A
The device was made by mixing electron transport layer(TPBI) and emitting layer(DPVBi) in the ratio 1:1.This design could confine the exciton recombination at the mixed layer,and EL emission spectrum is the same.As a result,,it enhance luminous behavior and the max luminance is 12519.43 cd/m2.In other hand,when the mixed ratio change from 1:1 to 2:1,the electron-hole balance is achieved in the emitting layer and high currenent density is shown at low operation voltage.The performance has shown the external quantum efficiency and luminous power efficiency are 2.37% and 2.10 cd/A,respectively.
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