TRPL of MAPbBr3, MAPbI3, and FAPbBr3 was measured by a home-built setup. A 405 nm pulsed femtosecond laser (Mai Tai) with a repetition rate of 4 MHz was focused onto the surface of the sample using an objective lens (Olympus, 20×, SApo, NA = 0.7), generating a Gaussian-distribution spot with a FWHM of 1366 nm (for FAPbBr3, the repetition rate was 0.5 MHz). All measurements were done with an average incident power of ≈40 nW. Then, the PL from the photoexcitation, together with the reflected and scattered excitation signal, was collected by the same objective lens. The resulting collimated beam passed through a long-pass filter with a cutoff at λ = 425 nm to remove the reflected and scattered excitation light. The resulting PL signal was further collected through a multimode fiber (Thorlabs, 50 μm in diameter, 5 m) with a pair of coupler and collimator (Thorlabs RC08FC-P01) and sent to an APD (MPD PDM Series 20 μm), which was attached to the timing electronics (PicoQuant PicoHarp 300).
The TRPL of MAPbCl3 was measured by a home-built setup. 515 nm femtosecond laser was used to excite PL signal by two-photon absorption. A 450 nm short pass filter was used to remove the reflected and scattered excitation light. The resulting PL signal was further collected and sent to an APD (MPD PDM Series 20 μm) which is attached to the timing electronics (PicoQuant PicoHarp 300).
The TRPL of MAPbCl3 was measured by a home-built setup. 515 nm femtosecond laser was used to excite PL signal by two-photon absorption. A 450 nm short pass filter was used to remove the reflected and scattered excitation light. The resulting PL signal was further collected and sent to an APD (MPD PDM Series 20 μm) which is attached to the timing electronics (PicoQuant PicoHarp 300).