Organic-Inorganic Layered and Hollow Tin Bromide Perovskite with Tunable Broadband Emission

Pengfei Fu, Menglin Huang, Yuequn Shang, Na Yu, Hao-Long Zhou, Yue-Biao Zhang, Shiyou Chen,* Jinkang Gong, and Zhijun Ning* 
ACS Appl. Mater. Interfaces 201810, 34363–34369
Recently, layered perovskites attracted great attention for its excellent stability and light-emitting property. However, most of them rely on the toxic element lead and their emission quantum yields are generally low. Here, a unique hollow two-dimensional perovskite was developed in which the organic hexamethylene diamines (C6H18N22+) strongly coupled with distorted tin bromide anions (SnBr64–). This toxic-free low-dimensional tin perovskite exhibits a broadband emission in the visible region with a high luminescence quantum yield of 86%. First-principles calculation indicate the broadband emission is associated with the recombination of self-trapped excitons. And the emission is related to the geometry of tin bromide anions. An ultraviolet light-pumped white light emitting diode with excellent color-rendering index of 94 was fabricated using it together with a commercially available blue phosphor.