Charge Injection at the Heterointerface in Perovskite CH₃NH₃PbI₃ Solar Cells Studied by Simultaneous Microscopic Photoluminescence and Photocurrent Imaging Spectroscopy

Abstract

Charge carrier dynamics in perovskite CH3NH3PbI3 solar cells were studied by means of microscopic photoluminescence (PL) and photocurrent (PC) imaging spectroscopy. The PL intensity, PL lifetime, and PC intensity varied spatially on the order of several tens of micrometers. Simultaneous PL and PC image measurements revealed a positive correlation between the PL intensity and PL lifetime, and a negative correlation between PL and PC intensities. These correlations were due to the competition between photocarrier injection from the CH3NH3PbI3 layer into the charge transport layer and photocarrier recombination within the CH3NH3PbI3 layer. Furthermore, we found that the decrease in the carrier injection efficiency under prolonged light illumination leads to a reduction in PC, resulting in light-induced degradation of solar cell devices. Our findings provide important insights for understanding carrier injection at the interface and light-induced degradation in perovskite solar cells.

Effects of energetics with {001} facet-dominant anatase TiO2 scaffold on electron transport in CH3NH3PbI3 perovskite solar cells

“…These trends of injection and recombination kinetics affected by the contacted facet were also consistently observed with the trend of photoluminescence (PL) and photoluminescence lifetime (PLLT) under open-circuit [80] and short-circuit configurations [81], in order to confirm the trend of recombination and injection kinetics, respectively (S5). As previous report suggested that the lifetime under open-circuit configuration are directly related to the density of non-radiative recombination arisen from defect-related recombination center, longer lifetime PL indicates the suppression of bimolecular recombination under open-circuit configuration results in higher intensity of PL and thus high V OC in solar cell devices [80].…”

“…As previous report suggested that the lifetime under open-circuit configuration are directly related to the density of non-radiative recombination arisen from defect-related recombination center, longer lifetime PL indicates the suppression of bimolecular recombination under open-circuit configuration results in higher intensity of PL and thus high V OC in solar cell devices [80]. On the other hand, the quenching rate of PL under shortcircuit configuration is also directly related to the electron injection from photo-excited perovskite crystals to n-type semiconductors [81]. The results of the shorter lifetime in PLLT was observed as {001} fraction increased, and thus these results support the discussion of electron transfer process at TiO 2 /perovskite interfaces, which can be enhanced by {001} facet as mentioned above.…”

Local Crystal Misorientation Influences Non-radiative Recombination in Halide Perovskites

“…Grain boundaries and surface traps act as centers for non-radiative recombination in many materials, including halide perovskites. [5][6][7]12,13,21,53,[58][59][60][61][62][63][64][65] Instead, the point we are making is that local crystal orientation is also important, perhaps more so than grain size in some films. Ideally, we would want films with larger grain sizes and low orientation spread within a grain, i.e.…”

Poly(3‐hexylthiophene)/Gold Nanorod Composites as Efficient Hole‐Transporting Materials for Perovskite Solar Cells

“…The TRPL spectra shown in Figure b were fitted to a biexponential decay, and the obtained parameters are shown in Table S1, Supporting Information. A 1 ( A 2 ) and τ 1 ( τ 2 ) are the amplitude and the lifetime of fast (slow) component of a fast decay and a slow decay process, respectively . The τ 2 lifetime decreased from 58.86 ns for the pristine perovskite to 31.30 ns for the perovskite covered with P3HT.…”