Instantaneous Photocarrier Transport at the Interface in Perovskite Solar Cells to Generate Photovoltage
Instantaneous Photocarrier Transport at the Interface in Perovskite Solar Cells to Generate Photovoltage
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DOI：
10.3390/photonics9050316
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发表时间：
2022-05
期刊：
影响因子：
2.4
通讯作者：
T. Mochizuki;I. Kawayama;M. Tonouchi;Y. Nishihara;Msayuki Chikamatsu;Y. Yoshida;H. Takato
中科院分区：
文献类型：
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作者：
T. Mochizuki;I. Kawayama;M. Tonouchi;Y. Nishihara;Msayuki Chikamatsu;Y. Yoshida;H. Takato
通过评估激光诱导的太赫兹（THz）发射来评估钙钛矿太阳能电池的瞬时光载流子传输，以了解钙钛矿太阳能电池中的载流子动力学。使用太赫兹时域光谱测量了具有不同外部偏压的 n-i-p 钙钛矿太阳能电池的 TiO2 电子传输层和钙钛矿活性层之间界面的激光诱导太赫兹辐射波形。太赫兹辐射的幅度随着反向偏压的增加而减小。太赫兹辐射的波形在强反向偏压下发生反转。测量的偏置电压依赖性表明，由于电子迁移率高于空穴，即光登伯效应，在钙钛矿和TiO2界面处产生的瞬态电流是太赫兹辐射的主要来源，当反向偏压引起强界面电场时，界面电场的破坏性贡献使瞬态电流反转。界面电场的显着贡献之前在钙钛矿薄膜中尚未报道过，并且是太阳能电池所独有的。我们相信，钙钛矿太阳能电池界面处的能带弯曲将通过适当的建模从太赫兹发射中确定。
The instantaneous photocarrier transport of perovskite solar cells was evaluated by assessing laser-induced terahertz (THz) emission to understand carrier dynamics in perovskite solar cells. The waveform of laser-induced THz radiation from an interface between the TiO2 electron transport layer and perovskite active layer of an n-i-p perovskite solar cell with varying external bias was measured using THz-time domain spectroscopy. The amplitude of the THz radiation decreased with increasing reverse bias voltage. The waveform of the THz radiation was inverted at a strong reverse bias. The measured bias voltage dependence suggests that the transient current generated at the interface between perovskite and TiO2 owing to the higher mobility of electrons than that of holes, namely the photo-Dember effect, is the dominant source of THz radiation and the destructive contribution of the interfacial electric field inverts the transient current when a reverse bias causes a strong interfacial electric field. The significant contribution of the interfacial electric field has not been previously reported in perovskite thin films and is unique to solar cells. We believe that band bending at interfaces in perovskite solar cells will be determined from the THz emission with proper modeling.