Blue perovskite LEDs dependent on temperature optical properties

Obtaining thermally stable blue light-emitting devices has been a long-standing challenge facing researchers. Primary color perovskite-LEDs (PeLEDs) potentially have industrial applications in semiconductor technology.

Jiang et al. studied chlorine-based organometallic halide perovskite (Cl-OHP) films and their applications in blue PeLEDs. The authors developed an excitonic luminescence model to understand the temperature-dependent optical properties of the Cl-OHP.

“The investigation of the temperature dependence of PeLEDs and absorption spectra is an applicable method that can observe the optical properties of semiconductors, such as exciton behavior and light emission,” said author Fei Xu. “This could provide a deep insight to understand the photophysical properties and luminance models in semiconductor materials and devices.”

To obtain stable Cl-OHP films, they used a hybrid sequential deposition process. The authors identified a temperature-dependent nonmonotonous photoluminescent peak shift, which they believe could be caused by the competition between Stokes effect and bandgap widening. An abnormal increase of the Stokes shift affects photoluminescent peak shifting, but at a high temperature range, the temperature dependence of the optical bandgap could not reflect photoluminescent peak shift.

The authors hope to apply this research to prepare high quality Cl-OHPs and develop high efficiency blue PeLED devices.

“Although some perovskite nanomaterials showed high photoluminescence quantum yields, the device performance typically becomes worse. We believe that novel device structures and high-quality perovskite materials are key success factors to improve blue PeLEDs,” said Xu. “Our research helped to unveil the excitonic blue luminescent processes of Cl-OHP, providing a guidance for constructing highly efficient blue PeLEDs.”

Source: “Temperature-dependent nonmonotonous evolution of excitonic blue luminescence and Stokes shift in chlorine-based organometallic halide perovskite film,” Beng Jiang, Yue Li, Jiabin Zhu, Ziting Hu, Xuemeng Zhou, Yan Zhang, Ming Gao, Wenzhen Wang, Zuimin Jiang, Zhongquan Ma, Lei Zhao, Teng Chen, Zhan Xu, Haitao Xu, Fei Xu, Run Xu, and Feng Hong, Applied Physics Letters (2020). The article can be accessed at https://doi.org/10.1063/1.5135389 .