Photoluminescent registration of fullerite C$_{60}$ derivatives during chemical interaction with H$_{2}$ and N$_{2}$ molecules

TL;DR

This study investigates the photoluminescent properties of fullerite C60 derivatives after chemical interaction with H2 and N2 molecules at low temperatures, revealing new luminescent substances and spectral shifts.

Contribution

First-time registration of low-temperature photoluminescence from fullerite derivatives formed during chemical interactions with H2 and N2, identifying new fullerane and azafullerene compounds.

Findings

Identification of photoluminescence from fulleranes C60Hx.

Detection of azafullerene dimer (C59N)2 in N2 reaction products.

Spectral shifts indicating formation of new chemical compounds.

Abstract

Single crystals of C$_{60}$ saturated with molecular hydrogen and nitrogen were studied using the spectral-luminescent method of registration in the quantum counting mode at a low temperature of 20 K. Previously, it was found that the temperature limit of the adsorption crossover (the transition from the diffusion mechanism of intercalation - physisorption to chemical interaction - chemisorption) for fullerite C$_{60}$ in an H$_{2}$ atmosphere is about 525 K, and in an N$_{2}$ atmosphere 695 K, respectively. At saturation temperatures above those indicated, the process of chemical interaction of impurity molecules and the fullerite matrix occurs with the formation of new compounds. Therefore, saturation was carried out at temperatures of 570 K for hydrogen and 720 K for nitrogen under a pressure of 30 atm. For the first time, the results of registration of photoluminescent radiation at low temperatures from new substances based on fullerite C60 are presented. A mixture of weakly saturated fulleranes C$_{60}$H$_{X}$ was obtained by saturation of hydrogen from the gas phase at a temperature close to the sorption crossover temperature, and their low-temperature photoluminescence was identified for the first time. The analysis of the "blue" shift of the beginning of the spectrum of such radiation allowed us to more accurately attribute the obtained material to the initial segment of the fullerane series. The presence of radiation of the azafullerene dimer (biazafullerene) (C$_{59}$N)$_{2}$ in the spectra of the reaction products of C$_{60}$ with N$_{2}$ was also detected. It was shown that for polycrystalline samples of C$_{60}$ saturated in a nitrogen atmosphere, the characteristic luminescence of biazafullerene with a maximum at 1.53 eV determines the intensity and shape of the entire short-wave part of the emission spectrum of the complex of synthesized substances.