A General Solvent Selection Strategy for Solution Processed Quantum Dots Targeting High Performance Light‐Emitting Diode

• Published in: Advanced functional materials Vol. 27; no. 1; pp. np - n/a
• Main Authors: Zou, Yatao, Ban, Muyang, Cui, Wei, Huang, Qi, Wu, Chen, Liu, Jiawei, Wu, Haihua, Song, Tao, Sun, Baoquan
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.01.2017
• Subjects: Defects; Devices; Dissolution; Light emitting diodes; Materials science; Morphology; Optoelectronic devices; Quantum dots; Quantum efficiency; Solubility; solvent selection; Solvents; Strategy; Striation; striation defect; Striations; surface tension
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201603325

An all‐solution‐processed quantum dots (QDs) light emitting diode (QLED) consists of different layers deposited from various orthogonal solvents. Here, the authors develop a general solvent selection strategy to obtain orthogonal solubility properties as well as high film quality. It is found that a “poor” QDs film morphology with striation defects often occurs when the QDs film is deposited from “bad” solvent. A physical model is presented to rationalize the observed striation defects, and then a general solvent selection strategy is proposed to prevent both surface striation defects and the dissolving of the underlying layers by carefully choosing the “good” solvent for QDs. A compact QDs film can be fabricated without altering the original morphology of underlying functional layers in a QLED device, leading to significant device performance improvement. An external quantum efficiency of 15.45% is achieved in a green QLED with uniform emitting region. This solvent selection strategy provides a general way to deposit high quality films for most of the solution‐processed multilayer optoelectronic devices. A general solvent selection strategy for all‐solution‐processed light‐emitting quantum dots is proposed in which a “good” orthogonal solvent for quantum dots should prevent both surface striation defects and the dissolving of the underlying layers. Based on this strategy, an external quantum efficiency of 15.45% is achieved for a quantum dots light‐emitting diodes device with uniform green emitting region.