Hot carriers in metal halide perovskite solar cells

A systematic set of measurements including simultaneous power-dependent (PDPL) and temperature-dependent photoluminescence (TDPL), and current-voltage (J-V) measurements were performed to probe the hot carriers and electron-phonon coupling in operational solar cells. These measurements support the presence of hot carriers in the device in advance of any negative effects due to halide segregation or materials decomposition. Indeed, the competition between hot carrier dynamics and photo induced halide segregation are shown to be strongly dependent upon temperature. At 100K, clear evidence of hot carriers was observed via increasing broadening of the high energy tail of the PL coupled with ballistic transport in J-V. At room temperature, however, the blue shift in the PL and high energy broadening characteristic of hot carrier generation at higher laser excitation are shown to compete with a gradual redshift in the PL peak energy as photo induced degradation begins to occur at higher lattice temperatures.