Experimental and theoretical investigation of 2D nanoplatelet-based conversion layers for color LED microdisplays

In the field of augmented reality, there is a need for very bright color microdisplays to meet the user specifications. Today, one of the most promising technology to manufacture such displays involves a blue micro-LED technology and quantum dots-based color conversion layers. Despite recent progress, the external power conversion efficiencies (EPCE) of these layers remain under similar to 25%, below the needs (>40%) to reach a white luminance of 100,000 cd/m(2). In this work, we have synthesized CdSexS1-x nanoplatelet-based conversion layers for red and green conversion, and measured their absorption properties and EPCE performances with respect to layer thickness. On this basis, a model was developed that reliably predicts the layer EPCE while using only few input data, namely the layer absorption coefficients and the photoluminescence quantum yield (PLQY) of color photoresist. It brings a new insight into the conversion process at play at a micro-LED level and provides a simple method for extensive optimization of conversion materials. Finally, this study highlights the outstanding red conversion efficiency of photoresist layers made of core-double shell CdSexS1-x nanoplatelets with 31% EPCE (45% external PLQY) for 8 mu m-thick conversion layer. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The study investigates the performance of CdSexS1-x nanoplatelet-based conversion layers for red and green conversion, proposing a model that reliably predicts layer EPCE and provides a simple method for optimization of conversion materials. It highlights the outstanding red conversion efficiency of photoresist layers made of CdSexS1-x nanoplatelets.