Femtosecond Excitonic Relaxation Dynamics of Perovskite on Mesoporous Films of Al₂O₃ and NiO Nanoparticles

Abstract

The excitonic relaxation dynamics of perovskite adsorbed on mesoporous thin films of Al2O3 and NiO upon excitation at 450 nm were investigated with femtosecond optical gating of photoluminescence (PL) via up-conversion. The temporal profiles of emission observed in spectral region 670-810 nm were described satisfactorily with a composite consecutive kinetic model and three transient components representing one hot and two cold excitonic relaxations. All observed relaxation dynamics depend on the emission wavelength, showing a systematic time-amplitude correlation for all three components. When the NiO film was employed, we observed an extent of relaxation proceeding through the non-emissive surface state larger than through the direct electronic relaxation channel, which quenches the PL intensity more effectively than on the Al2O3 film. We conclude that perovskite is an effective hole carrier in a p-type electrode for NiO-based perovskite solar cells showing great performance.

Oxidized Ni/Au Transparent Electrode in Efficient CH3NH3PbI3 Perovskite/Fullerene Planar Heterojunction Hybrid Solar Cells

“…[ 3,5 ] The electrode interlayer is critical to improve the transport of charges at the ITO/CH 3 NH 3 PbI 3 perovskite interface and thus the photovoltaic parameters. [ 10,[31][32][33] We have successfully applied a p-type, semiconducting, inorganic nickel oxide (NiO x ) thin layer to substitute PEDOT:PSS [34][35][36][37] and hybrid perovskite COMMUNICATION should be noted in Scheme 1 c that the formation of an interconnected Au network embedded inside the transparent NiO layer leads to both a suitable electrode and electrode interlayer for the fabrication of perovskite-based hybrid solar cells. Both the electrode and electrode interlayer can be prepared on the glass substrate by a single thermal oxidation treatment.…”

Charge Transfer Dynamics from Organometal Halide Perovskite to Polymeric Hole Transport Materials in Hybrid Solar Cells

“…23 The fast (subpicosecond) spectral narrowing and red shift of the 760 nm band has been explained either by band filling effects following a Burnstein−Moss model 24 or by stimulated emission from thermally nonrelaxed states. 15,25 The TAS spectra of the samples with thin polymeric HTMs ( Figure 1, see also Supporting Information Figure S2 and S3) are also dominated by the spectral features of CH 3 NH 3 PbI 3 . Figure 1C shows the TAS time profiles following 600 nm excitation probed at different wavelengths.…”

A Rutile TiO2 Electron Transport Layer for the Enhancement of Charge Collection for Efficient Perovskite Solar Cells

“…[11][12][13][14] TiO 2 is the common ETL material used in highly efficient PSCs, owing to its suitable conduction band, facial and variable deposition methods,c hemical stability,a nd low cost. [11][12][13][14] TiO 2 is the common ETL material used in highly efficient PSCs, owing to its suitable conduction band, facial and variable deposition methods,c hemical stability,a nd low cost.…”