Composite exciton recovery layer-based pure inorganic perovskite light-emitting diode and preparation method thereof

Abstract

The invention provides a composite exciton recovery layer-based pure inorganic perovskite light-emitting diode and a preparation method thereof. A PeLED is prepared through inserting a TmPyPB:FIrpic composite exciton recovery layer between an EML (CsPbBr3) and an electron transport layer (TmPyPB), and all singlet and triplet excitons generated on an EML/TmPyPB:FIrpic interface can be utilized foremitting light. According to the prepared device with the best performance, the threshold voltage is about 3.4V, the maximum brightness is about 14363cd/m<2>, the maximum current efficiency is about 4.9cd/A, the maximum EQE is about 1.26% and the performance of the device is significantly improved.

Description

technical field [0001] The invention relates to the technical field of film preparation, in particular to a pure inorganic perovskite light-emitting diode based on a composite exciton recovery layer and a preparation method thereof. Background technique [0002] In recent years, due to the excellent optoelectronic properties such as low cost, high photoluminescence quantum yield (PLQY, ~95%), ambipolar carrier transport, and long exciton diffusion distance, organic-inorganic hybrids based on solution processing have Perovskites have attracted more and more attention. In perovskite solar cells, a power conversion efficiency of 22.1% has been achieved, which is on par with that of traditional inorganic semiconductor photovoltaic materials. Besides, in PeLEDs, Cho et al. achieved an external quantum efficiency of ~8.53% using nanocrystal pinning (NCP) in 2014, which is close to the level in conventional organic light-emitting diodes (OLEDs). Although organic-inorganic hybrid ...

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Problems solved by technology

Although organic-inorganic hybrid perovskite materials have made great progress in the field of solar cells and luminescence, the stability of PeLEDs based on organic-inorganic hybrid perovskites has always been a key issue restricting their further development.

[0003] In 2015, the first CsPbBr-based 3 The thin-film PeLED was fabricated by Kulbak et al. However, due to the immature technology at that time, the device only achieved a current efficiency of ~1cd / A

However, inserting an exciton-recycling layer between the charge-transport layer and the perovskite light-emitting layer (EML) to improve the performance of PeLEDs has rarely been reported, although traditional exciton-blocking materials (such as POSS, etc.) and charge-transport materials ( Such as TFB, CBP, TPBi, TmPyPB, etc.) can also confine singlet excitons between the EML / charge transport layer, but since these exciton blocking layers and carrier transport layers are fluorescent materials, it will lead to a large number of The triplet excitons are annihilated in a non-radiative way, and the excitons in the light-emitting layer are not fully utilized to emit light

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