A clear understanding of excited carrier relaxation to their equilibrium state via carrier-phonon, carrier-carrier interaction etc. is always required for the advancement of perovskite based device performance. Organic/inorganic lead halide perovskite have shown remarkable slow hot carrier cooling properties. Herein, we investigate the effect of hot phonon and Auger heating on hot carrier relaxation dynamics in Methyl-ammonium lead iodide-chloride (CH₃NH₃PbI $_{\mathrm {3-X}}$ Cl_X or mixed halide) perovskite using transient absorption spectroscopy. The reduced energy-loss rate on sub-picosecond time scale clearly shows the non-equilibrium build-up of longitudinal optical and acoustic phonon modes (carrier-phonon interaction) at low pump excitation (10¹⁸ cm⁻³). However at high pump excitation (10¹⁹ cm⁻³), dominating Auger heating process (carrier-carrier interaction) further reduces the energy-loss rate by more than two order of magnitude and delays the carrier relaxation process to tens of picoseconds which makes perovskite as a promising candidates in hot carrier photovoltaic.

中文翻译：

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热声子和俄歇加热介导混合卤化物钙钛矿中的慢带内载流子弛豫

为了提高基于钙钛矿的器件性能，始终需要清楚地了解通过载流子-声子、载流子-载流子相互作用等激发的载流子弛豫到其平衡状态。有机/无机卤化铅钙钛矿已显示出显着的慢热载流子冷却特性。在此，我们研究了热声子和俄歇加热对甲基铵碘化铅-氯化物 (CH ₃ NH ₃ PbI) 中热载流子弛豫动力学的影响 $_{\mathrm {3-X}}$ Cl _X或混合卤化物）钙钛矿使用瞬态吸收光谱。在亚皮秒时间尺度上降低的能量损失率清楚地显示了在低泵浦激发（10 ¹⁸ cm ^-3）下纵向光学和声学声子模式（载流子-声子相互作用）的非平衡积累。然而，在高泵激（10 ¹⁹ cm ^-3）下，主导俄歇加热过程（载流子相互作用）进一步降低了两个数量级以上的能量损失率，并将载流子弛豫过程延迟到几十皮秒，这使得钙钛矿作为热载流子光伏的有前途的候选者。