Ruby Nanoparticles for Greenhouse Farming: Synthesis, Features and Application

In this work, we investigated the effect of photoconversion covers based on ruby (chromium-doped alumina (Al2O3:Cr3+)) particles (PCC-R) on the growth and development of lettuce (Lactuca sativa) plants. Ruby particles (from 100 nm to 2 mu m) were obtained by the sequential application of spall laser ablation and further laser fragmentation. The content of chromium ions relative to aluminum ions in the nanoparticles was 3.3 x 10(-3). The covers with different densities of applied ruby particles (2 x 10(7) m(-2) (PCC-R7), 2 x 10(8) m(-2) (PCC-R8), 2 x 10(9) m(-2) (PCC-R9)) were studied in the present work. The PCC-Rs had two wide bands of luminescence excitation. The first one was from 350 nm to 450 nm with a maximum at 405 nm, and the second one was from 500 nm to 600 nm with a peak at 550 nm. Synthesized covers emitted in the range of 650 nm to 750 nm, with a peak at 695 nm. It has been shown that PCC-R8, in contrast to PCC-R7 and PCC-R9, provided an increase in yield by 40% and was characterized by increased water use efficiency during dark respiration and assimilation of carbon dioxide in plants. It is assumed that the observed positive effect of PCC-R8 photoconversion covers is associated with the activation of regulatory mechanisms due to a qualitative change in the light spectrum.