Panoramic Synthesis as an Effective Materials Discovery Tool: The System Cs/Sn/P/Se as a Test Case.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• Traditional synthesis methods analyze only final products, overlooking transient intermediates.
• This lack of insight into reaction pathways hinders the discovery of new materials and understanding of formation mechanisms.
• Emerging in situ monitoring techniques offer potential for real-time reaction analysis.

Purpose of the Study:

• To demonstrate the utility of in situ synchrotron X-ray diffraction for comprehensive reaction monitoring.
• To identify and characterize novel crystalline phases formed during the synthesis of Cs/Sn/P/Se materials.
• To introduce and validate the 'panoramic synthesis' approach for materials discovery.

Main Methods:

• In situ synchrotron X-ray diffraction (XRD) was employed to study the Cs/Sn/P/Se system.
• Powder mixtures were heated to 650 °C with continuous XRD data acquisition during heating and cooling.
• Diffraction data was analyzed to track phase evolution as a function of temperature.

Main Results:

• Seven known crystalline phases (Sn, Cs2Se3, Cs4Se16, Cs2Se5, Cs2Sn2Se6, Cs4P2Se9, Cs2P2Se8) were identified.
• Six previously unknown crystalline phases were detected during the in situ experiment.
• Three novel compounds (Cs4Sn(P2Se6)2, α-Cs2SnP2Se6, Cs4(Sn3Se8)[Sn(P2Se6)]2) were successfully isolated and characterized ex situ.
• The novel compound Cs4(Sn3Se8)[Sn(P2Se6)]2 exhibits interesting semiconductor and semimetal properties.

Conclusions:

• The 'panoramic synthesis' approach, utilizing in situ synchrotron XRD, provides a complete view of phase formation during reactions.
• This method significantly enhances the discovery of new materials by revealing transient intermediates and unknown phases.
• The successful isolation and characterization of novel Cs/Sn/P/Se compounds validate the effectiveness of panoramic synthesis.