Upconversion nanoparticles (UCNPs) have unique photonic properties that make them ideally suited for many applications. They are excited by low-energy near-infrared photons and emit at higher energy (typically visible) wavebands. However, synthesis of UCNPs requires either high pressure reaction chambers or inert atmospheres. Combined with the requirements for high-temperatures (200 to 400 °C) and long reaction times (e.g. up to 24 hours), these place barriers to entry for UCNP research, in terms of both financial barriers and knowledge/"know how". These constraints may also limit the scale of UCNP production for end-user applications.

We adapted and further developed a method for producing UCNPs with simple laboratory equipment, i.e. a hot-plate and beakers. No pressure vessel or inert atmosphere is required. The UCNPs produced have a polyvinylpyrrolidone (PVP) polymer coating, with strong red emission due to Mn²⁺ co-doping within the UCNP crystal lattice. It was found that UCNPs of composition NaYF₄:Yb,Er,Mn  (Yb = 20 mol %, Er = 2 mol%, Mn = 35 mol%) maximised the red emission whilst also minimising the diameter of the UCNPs to 36 ± 15 nm. These combination of optical and physical properties should make these UCNPs ideal for further development and exploitation, particularly for biological applications where red emission can penetrate over a centimetre of tissue.

This dataset and software accompanies the manuscript 'Low-temperature open-air synthesis of PVP-coated NaYF_4:Yb,Er,Mn upconversion nanoparticles with strong red emission', which was published in Royal Society Open Science on 19th January 2022. https://doi.org/10.1098/rsos.211508

The dataset comprises data characterising upconversion nanoparticles  synthesised  via the PVP40 route. The data is primarily transmission electron microscopy (TEM) images, scanning electron microscopy (SEM) images, powder x-ray diffraction (XRD) patterns, and upconversion luminesence emission spectra. Data is provided alongside custom-written Matlab scripts for processing and display of data where appropriate.

Please refer to README file.