Efficient Perovskite Light‐Emitting Diodes with a Siloxane‐Blended Organic Hole Transport Layer

• Published in: Advanced photonics research 2022-10, Vol.3 (10), p.n/a
• Main Authors: Matsushima, Toshinori, Nasu, Ryotaro, Takekuma, Kotaro, Ishii, Tomohiro, Feng, Zhao, Tang, Xun, Nakamura, Nozomi, Tumen-Ulzii, Ganbaatar, Adachi, Chihaya
• Format: Article
• Language: English
• Subjects: Chemical bonds; Electrons; hole transport layer; Light emitting diodes; perovskite light-emitting diode (LED); poly(N-vinylcarbazole) (PVCz); siloxane; Spectrum analysis; tetraethyl orthosilicate (TEOS)
• ISSN: 2699-9293; 2699-9293
• DOI: 10.1002/adpr.202200003

Metal halide perovskite light‐emitting diodes (LEDs) are promising for future display applications because of their excellent advantages, such as high external quantum efficiency, emission color tunability, and high emission color purity. Although solution processing widely used for perovskite film fabrication is an additional advantage, there are cases in which fabricating a perovskite‐emitting layer with spin‐coating results in the dissolution of an underlying organic hole transport layer (HTL). As a result, since a perovskite layer comes into partial contact with an indium tin oxide (ITO) anode layer, excited states formed in a perovskite‐emitting layer are quenched by charge transfer to ITO. In this study, it is shown that adding tetraethyl orthosilicate (TEOS) into a HTL material of poly(N‐vinylcarbazole) (PVCz) is an effective method used to overcome this issue. Upon heating, the hydrolysis reaction of TEOS molecules takes place in PVCz films to form a siloxane network, which makes PVCz films insoluble and, therefore, alleviates the excited‐state quenching. It is demonstrated that using the siloxane‐blended PVCz HTL increases external quantum efficiencies of perovskite LEDs to 15.4 ± 0.3% from the original 10.4 ± 0.3% by about 1.5 times. Dissolution of an underlying organic transport layer during spin‐coating of a metal halide perovskite layer has been an issue. Herein, a facile, effective method used to make an organic transport layer insoluble in an organic solvent by using tetraethyl orthosilicate is shown. With this method, an increase in external quantum efficiency of perovskite light‐emitting diodes is demonstrated.