# Highly efficient and ultrahigh-resolution quantum dot light-emitting diodes via photoisomeric transformation

## TL;DR

This paper introduces a new method using photoisomeric transformation to create high-resolution, efficient quantum dot displays with record performance.

## Contribution

A novel photoisomeric strategy that suppresses non-radiative energy transfer, enabling high-efficiency and high-resolution quantum dot devices.

## Key findings

- The method achieves a record efficiency of 24.5% and resolution of 15,800 PPI for quantum dot devices.
- The approach is compatible with both CdSe/ZnS and perovskite quantum dots on rigid and flexible substrates.
- The technique enables small-sized, multicolor, and high-fidelity quantum dot pixels.

## Abstract

The direct photopatterning technique provides a straightforward approach for high-resolution quantum dot (QD) patterns for next-generation displays. However, the extensively deteriorated QD optical properties deriving from the changes of the QD surface states and/or surroundings set substantial limitations in obtaining high-quality QD patterns and efficient electroluminescent devices. Here, we propose an ingenious and effective approach by utilizing the photoisomeric transformation from spiropyran to merocyanine for highly emissive QD patterns. We reveal the suppression of non-radiative energy transfer between QDs and the dissociative merocyanine for fast luminescence recovery. We achieve small-sized (0.8 μm), high-resolution (15,800 pixels per inch, PPI), high-fidelity (~100%), multicolor, and elaborated QD pixels, and showcase their good compatibility for CdSe/ZnS and perovskite QD pixel fabrication, as well as on both rigid and flexible substrates. These merits promote highly performing pixelated devices with a large luminance of 35,534 cd m−2 and a record efficiency of 24.5% at 6350 PPI among the direct photopatterning devices. Furthermore, we verify the wide applicability of the proposed strategy for high-performance pixelated perovskite devices with an efficiency of 13.8% at 1760 PPI. The above results confirm the great value of the proposed approach for high-quality QD patterns and high-performance pixelated devices.

We reveal the suppression of non-radiative energy transfer between QDs and the photoisomeric merocyanine for greatly improved luminescence after patterning, achieving a record efficiency (24.5%) and resolution (15,800 PPI) among direct photopatterning approaches.