Spatial microheterogeneity in the valence band of mixed halide hybrid perovskite materials

• The valence band of lead halide hybrid perovskites with a mixed I/Br composition is investigated using electronic structure calculations and complementarily probed with hard X-ray photoelectron spectroscopy. In the latter, we used high photon energies giving element sensitivity to the heavy lead and halide ions and we observe distinct trends in the valence band as a function of the I : Br ratio. Through electronic structure calculations, we show that the spectral trends with overall composition can be understood in terms of variations in the local environment of neighboring halide ions. From the computational model supported by the experimental evidence, a picture of the microheterogeneity in the valence band maximum emerges. The microheterogeneity in the valence band suggests that additional charge transport mechanisms might be active in lead mixed halide hybrid perovskites, which could be described in terms of percolation pathways.

Subject headings

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Keyword

Electronic structure

Hybrid materials

Lead compounds

Perovskite

Photons

Solvents

X ray photoelectron spectroscopy

Computational modelling

Electronic structure calculations

Experimental evidence

Halide ions

Hard X-ray photoelectron spectroscopy

Lead ions

Local environments

Microheterogeneity

Photon energy

Valence-band maximums

Valence bands

Publication and Content Type

ref (subject category)

art (subject category)