Figure 1 | Scientific Reports

Figure 1

From: Simultaneous observation of free and defect-bound excitons in CH3NH3PbI3 using four-wave mixing spectroscopy

Figure 1

Upper left, schematic of four-wave mixing spectroscopy.

Two 40 fs input pulses and excite a carrier density grating, and the self-diffracted signal along is measured using a monochromator and photomultiplier detector as a function of the time delay. Lower left, methylammonium lead iodide perovskite ABX3, with A = CH3NH3, B = Pb, X = I. Center FWM response of the CH3NH3PbI3 sample at 10 K for excitation at 1.653 eV, 11 meV above the band gap. Upper Right, FWM signal at fixed values of detection photon energy, showing a smooth decay (oscillations) for energies above (below) band gap. Lower right, FWM spectrum at fixed values of time delay, indicating multiple spectrally-distinct signal contributions.

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