Cryo-optical setup for wide-field microscopy and spectroscopy of luminescent nanomaterials

Studying photoluminescence (PL) is essential for understanding and engineering light-emitting nanomaterials. Heterogeneous samples, such as thin films and microstructures, require characterization of the spatial distribution of PL intensity, spectra, lifetimes, and photon correlations at the microscale under variable temperatures. Here we describe a cryo-optical setup for micro-PL imaging, spectroscopy, lifetime, and photon bunching measurements that addresses this need. The system combines a home-built wide-field microscope with a commercial closed-loop helium cryostat, a spectrograph equipped with an sCMOS camera, and a Hanbury-Brown and Twiss interferometer (HBT-interferometer). Optical layout and components of the setup are described, and its performance is tested on samples of CsPbBr₃ nanocrystal superlattices. This work aims to demonstrate that it is feasible to develop an advanced microscopy and spectroscopy setup suitable for material scientists focused on developing novel materials, even if they initially lack extensive experience in advanced optical methods.