The luminescent properties of CuAlO₂

Abstract

aIn this work we examine the room temperature photoluminescence, Raman and low temperature photoluminescence properties of CuAlO 2 prepared using different precursors. At room temperatures the luminescence associated with bulk CuAlO 2 occurs at 355 nm and is associated with strong resonant Raman effects. At low temperatures we find that the UV emission is dominated by strong electronphonon coupling leading to a Franck-Condon type emission band. A second strongly phonon coupled band is also observed in the blue spectral region. In addition we also show that at low temperatures the luminescent properties of CuAlO 2 are meta-stable, with anomalous temperature dependence. The possible origins of the blue band, the meta-stability and anomalous temperature dependence are discussed.

Photoluminescence and photocatalytic properties of rhombohedral CuGaO2 nanoplates

“…The reports showed that all kinds of donor type intrinsic defects have high formation energy or have relatively deep transition energy levels, thus without the intentional doping, CuGaO 2 present p-type conductivity. To date, on account of the luminescence properties of CuGaO 2 has not been reported yet, we could conclude from CuAlO 2 luminescence properties that the defect emission peak of CuGaO 2 is more likely located in the range of 400–500 nm22. Temperature-dependent PL spectra of the defects emission are shown in Fig.…”

Thermoelectric and Transport Properties of Delafossite CuCrO2:Mg Thin Films Prepared by RF Magnetron Sputtering

“…Delafossite type oxides Cu I M III O 2 with M = (Fe, Al, Ga, Cr…) due to their large range of properties and the abundance of their constituent elements in the nature, have been studied for several applications such as transparent p-type conducting oxides (TCO) [10,11,12,13,14,15,16,17], transparent electronic devices [18,19,20,21,22,23,24,25], dye-sensitized solar cells [26,27,28,29], and photoelectrodes [30] but also for outstanding catalysis [31] and photo-catalysis [31,32,33,34,35,36,37,38,39,40,41], antibacterial [42], luminescence [43,44,45], gas and temperature sensing [46,47,48,49], magnetic and electric [50,51,52,53,54], energy storage [55], oxygen storage [56], water reduction [57], thermoelectricity and superconductivity [58] properties. In the oxide family, the cation Cu I is a monovalent metal and the cation M III is a trivalent metal.…”

Luminescence of delafossite-type CuAlO2 fibers with Eu substitution for Al cations

“…[36,37] The A modes correspond to the vibrational movements in the direction of Cu-O bonds and the E modes represent the vibrations in the perpendicular direction. A previous report on particulate CuAlO 2 [25] shows two sharp peaks at 418 and 767 cm -1 , respectively. However, the Raman scattering peaks could shift to a large extent depending on the trivalent ion species.…”

“…Since our experiments were performed at room temperature and no other peaks associated with Eu 3+ activators were observed from the emission spectra, the broad violet emission is unlikely from transition to defect levels. Byrne et al [25] recently observed a coexistence of both a near-band-edge UV emission and a blue emission at ~430 nm at 14.5 K, with almost 100 nm Stokes shift. Revisiting the study by Jacob et al [29] on CuYO 2 and CuLaO 2 , the prolific hybridization from Cu 4p/3d orbitals and the resultant  + 4s and - 4s splitting only give rise to an asymmetric and overlapped peak feature rather than large Stokes shift.…”

“…Our observation also confirmed the prediction that this Stokes shift would increase as the size of trivalent metal ion increases. [25] For all the doped samples at excitation wavelength of 365 nm, only the broad near-band-edge emission was identified and no peaks associated with Eu f-f transitions were observed above 500 nm. At higher excitation energies, the excitons near the band edge may undergo fast recombination across the band-gap and non-radiative relaxation to the ground state while the transitions to Eu activators become absent.…”