[15p-A401-1~17] 12.5 Organic and hybrid solar cells

▲ [15p-A401-8] Interface Engineering for Achieving Efficient and Low Hysteretic Behavior Perovskite Solar Cells Based on TiO₂ Mesopores Electron Extraction Layer

〇Liao YingHan¹, Chen ShihHsuan¹, Ho ChingMei¹, Chan ShunHsiang¹, Wu MingChung^1,2 (1.Chang Gung Univ., 2.Chang Gung Memorial Hospital at Linkou)

Keywords:perovskite solar cell, electron extraction layer, titanium dioxide

Solar energy has gained traction as renewable energy because of environmental pollution and global warming issues. The perovskite solar cells (PSC) have developed rapidly and focused on high power conversion efficiency, low cost, and easy fabrication. PSCs has been rapidly developing, and the power conversion efficiency (PCE) has achieved 25.7%. Even though the success of PSCs has been completed, the charge collection, defects between interfaces, and hysteresis phenomenon are substantial obstacles to the further development of such a technology. TiO₂ is widely used for the electron extraction layer (EEL) of PSCs due to its low cost, non-toxicity, chemical durability, optical stability, suitable conduction band, and high charge mobility. Enhancing the electron mobility of TiO₂ plays a critical role in carrier transportation and improves the conundrum of imbalanced electron and hole flux. It can also reduce the accumulated carrier at the interface, prevent them from recombination, and tune the band alignment between the EEL and perovskite active layer with the suitable dopant. That contributes to improving charge transportation in a device. Herein, we demonstrated various metal dopants (such as Ag, Zn, and Sn) in both planar and meso-TiO₂ EELs to enhance the PCE of PSCs. Among them, Sn-doped mesoporous EELs stood out from the series. The Sn-doped mesoporous structure TiO₂ improved the band alignment for EEL and perovskite active layer. The decreased defect states, improved carrier extraction ability, and the appropriate energy alignment facilitate the carrier transfer from the perovskite layer to the EELs. The promising PCE of 20.6% can be achieved from the PSC based on 1.0 mol% Sn-doped meso-TiO₂ EEL, and its hysteresis index from the corresponding devices can also be reduced from 0.16 to 0.03.