# Charge Carrier Regulation for Efficient Blue Quantum-Dot Light-Emitting Diodes Via a High-Mobility Coplanar Cyclopentane[b]thiopyran Derivative

## TL;DR

This paper introduces a new material to improve the efficiency of blue quantum dot light-emitting diodes by enhancing charge transport.

## Contribution

A novel high-mobility coplanar cyclopentane[b]thiopyran derivative is introduced to enhance hole transport in blue QLEDs.

## Key findings

- C8–SS increases hole mobility in PVK by two orders of magnitude.
- QLEDs with PVK:C8–SS show a low turn-on voltage of 3.2 V.
- The peak power efficiency reaches 7.13 lm/W, 2.65 times higher than control devices.

## Abstract

The performance of blue quantum dot light-emitting diodes
(QLEDs)
is limited by unbalanced charge injection, resulting from insufficient
holes caused by low mobility or significant energy barriers. Here,
we introduce an angular-shaped heteroarene based on cyclopentane[b]thiopyran (C8–SS) to modify the hole
transport layer poly-N-vinylcarbazole (PVK), in blue
QLEDs. C8–SS exhibits high hole mobility and conductivity
due to the π···π and S···π
interactions. Introducing C8–SS to PVK significantly
enhanced hole mobility, increasing it by 2 orders of magnitude from
2.44 × 10–6 to 1.73 × 10–4 cm2 V–1 s–1. Benefiting
from high mobility and conductivity, PVK:C8–SS-based
QLEDs exhibit a low turn-on voltage (Von) of 3.2 V. More importantly, the optimized QLEDs achieve a high
peak power efficiency (PE) of 7.13 lm/W, which is 2.65 times that
of the control QLEDs. The as-proposed interface engineering provides
a novel and effective strategy for achieving high-performance blue
QLEDs in low-energy consumption lighting applications.