Scientists develop near ambient pressure photoemission electron microscopy

A research group led by Prof. Fu Qiang and Prof. Bao Xinhe at the Dalian Institute of Chemical Âé¶¹ÒùÔºics (DICP) of the Chinese Academy of Sciences (CAS) have developed near ambient pressure photoemission electron microscopy (AP-PEEM) with a tunable deep-ultraviolet (DUV) laser source as the excitation source.
They designed and constructed a two-stage accelerating electrical field, a three-stage differential pumping system, and a near ambient pressure sample cell. PEEM imaging was demonstrated on sample surfaces in gaseous atmospheres up to 1 mbar. Spatial resolution reached 30 nm under the near ambient pressure conditions. Moreover, samples could be cooled down to 150 K or heated up to 1000 K when imaging. These performances were all successfully demonstrated in the lab onsite in November 2019.
PEEM is a powerful surface imaging technique for studying dynamic processes on solid surfaces. Nowadays, all PEEM measurements need to be performed under ultra-high vacuum (UHV) conditions, which present a large "pressure gap" compared to real applications.
The newly developed AP-PEEM can work under nearly realistic working conditions, suggesting important applications in heterogeneous catalysis, energy conversion devices, environmental processes, and biological science.
The AP-PEEM is combined with the tunable DUV laser source developed by Technical Institute of Âé¶¹ÒùÔºics and Chemistry of CAS. The entire DUV-AP-PEEM system was developed and installed in the State Key Lab of Catalysis of DICP, requiring more than five years.
Provided by Chinese Academy of Sciences