Perovskite/Polymer composites 

Abstract to Poster presented at Regional Mid-Atlantic ACS meeting

Hybrid organic-inorganic perovskite (OIP) nanocrystals have become very attractive due to high photoluminescence (PL) quantum yields, tunable bandgap, and narrow band emissions, all of which are crucial for new developments in photovoltaic and optical applications. Even though a lot of methods were developed to synthesize various OIP materials, there is still a need to improve processability, stability, and scalability of OIP materials. Our goal was to show that polymers can be used to prepare composite OIP materials with superior optical properties, that have the potential to be easily synthesized and scaled up. Polymers are a common choice for nanocrystalline OIP encapsulation, which improve stability and photoluminescent properties of the resulting material, yet, the exact effect of polymer chemical functionality on the resulting properties of the composite materials has not been thoroughly studied. In our study we show that polymer chemical composition directly impacts the morphology and photoluminescent properties of the composite perovskite material with approximately 75 wt% perovskite with respect to polymer. Specifically, we studied the effects of six different polymers, poly(styrene) (PS), poly(4-vinylpyridine) (P4VP), poly(ethyleneimine) (PEI), poly(ethylene oxide) (PEO), poly(vinylpyrrolidone) (PVP), and poly(methyl methacrylate) (PMMA) on the formation and properties of OIP nanocrystals during a facile one-step synthesis procedure. Combination of electron microscopy, infrared spectroscopy, and other characterization techniques confirmed that polymers with nitrogen-containing functional groups, amides, pyridine, and amines, preferentially bind and passivate perovskite surface defects, acting as macroligands. Nitrogen atoms act as Lewis base agents and coordinate with undercoordinated lead ions on the perovskite surface, which reduces the defect density and therefore promotes photoluminescent properties. Polymer passivation also promotes nanocrystalline formation of OIP, similar to typical growth of nanocrystals in other material systems moderated by small molecule ligands. With our work, we hope to establish a facile and potentially scalable method for creating composite materials with superior optical properties by using polymer macroligands.

Skills Acquired:

• Work with UV-Vis spectrophotometer

• Work with Fluorometer 

• Fourier Transform Infrared spectroscopy analysis

• X-ray diffraction analysis 

• Transmission electron microscopy image analysis

My Emphasis:

Advisor:

Dr. Robert Hickey: rjh64@psu.edu