Details

Autor(en) / Beteiligte

• Yao, Ji-Song
• Ge, Jing
• Wang, Kun-Hua
• Zhang, Guozhen
• Zhu, Bai-Sheng
• Chen, Chen
• Zhang, Qun
• Luo, Yi
• Yu, Shu-Hong
• Yao, Hong-Bin

Titel

Few-Nanometer-Sized α-CsPbI 3 Quantum Dots Enabled by Strontium Substitution and Iodide Passivation for Efficient Red-Light Emitting Diodes

Ist Teil von

• Journal of the American Chemical Society, 2019-02, Vol.141 (5), p.2069-2079

Ort / Verlag

United States

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Cubic phase CsPbI quantum dots (α-CsPbI QDs) as a newly emerging type of semiconducting QDs hold tremendous promise for fundamental research and optoelectronic device applications. However, stable and sub-5 nm-sized α-CsPbI QDs have rarely been demonstrated so far due to their highly labile ionic structure and low phase stability. Here, we report a novel strontium-substitution along with iodide passivation strategy to stabilize the cubic phase of CsPbI , achieving the facile synthesis of α-CsPbI QDs with a series of controllable sizes down to sub-5 nm. We demonstrate that the incorporation of strontium ions can significantly increase the formation energies of α-CsPbI QDs and hence reduce the structure distortion to stabilize the cubic phase at the few-nanometer size. The size ranging from 15 down to sub-5 nm of as-prepared stable α-CsPbI QDs allowed us to investigate their unique size-dependent optical properties. Strikingly, the few-nanometer-sized α-CsPbI QDs turned out to retain high photoluminescence and highly close packing in solid state thin films, and the fabricated red light emitting diodes exhibited high brightness (1250 cd m at 9.2 V) and good operational stability (L > 2 h driven by 6 V). The developed cation-substitution strategy will provide an alternative method to prepare uniform and finely size-controlled colloidal lead halide perovskite QDs for various optoelectronic applications.