AUTHOR=Zhou Wei , Han Peigeng , Luo Cheng , Li Cheng , Hou Jie , Yu Yang , Lu Ruifeng 

TITLE=Band-Gap and Dimensional Engineering in Lead-Free Inorganic Halide Double Perovskite Cs4Cu1-xAg2xSb2Cl12 Single Crystals and Nanocrystals

JOURNAL=Frontiers in Materials

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2022.855950

DOI=10.3389/fmats.2022.855950

ISSN=2296-8016

ABSTRACT=<p>Lead free double perovskites (DPs) are promising materials due to their non-toxic and tunable optical properties. In this work, a series of lead-free halide DP single crystals (SCs) and nanocrystals (NCs) (Cs<sub>4</sub>Cu<sub>1-x</sub>Ag<sub>2x</sub>Sb<sub>2</sub>Cl<sub>12</sub>) were reported. With alloying strategy, the optical band-gap engineering was realized and the dimension can be controlled between 2D and 3D. The Cu-alloyed SCs exhibit strong absorption from the UV-visible region to the near-infrared range (can even completely cover the bands of NIR-I and NIR-II). In addition, (Cs<sub>4</sub>Cu<sub>1-x</sub>Ag<sub>2x</sub>Sb<sub>2</sub>Cl<sub>12</sub>) NCs were synthesized via a top-down approach, which maintains similar optical properties and the dimensional transformation phenomenon to SCs. These results suggest the great potential of Cs<sub>4</sub>Cu<sub>1-x</sub>Ag<sub>2x</sub>Sb<sub>2</sub>Cl<sub>12</sub> SCs and NCs for photovoltaic and optoelectronic applications.</p>