Fig. 5: Potential application of longitudinal phase segregation in enhancing the hole extraction at perovskite/HTL interface.

a Evolution of TRPL spectra measured at the perovskite/HTL interface under continuous 420 nm illumination. The inset shows the TRPL measurement configuration. b Variation of I-rich emission intensity with illumination time in three illumination cycles. In each cycle, the crystal is subjected to continuous UV illumination for 300 s after which a PL spectrum is captured; the light is then switched off and the sample remains in dark for 15 min. Experimental data and fitting curves are shown in solid circles and lines respectively.