Solar electricity is an unlimited source of sustainable fuels, yet the efficiency of solar cells is limited. The efficiency of perovskite solar cells improved from 3.9% to reach 25.5% in just a few years. Perovskite solar cells are actually viewed as promising by comparison with dye-sensitized solar cells, organic solar cells, and the traditional solar cells made of silicon, GaAs, copper indium gallium selenide (CIGS), and CdTe. Here, we review bare and doped metal oxide electron transport layers in the perovskite solar cells. Charge transfer layers have been found essential to control the performance of perovskite solar cells by tuning carrier extraction, transportation, and recombination. Both electron and hole transport layers should be used for charge separation and transport. TiO₂ and 2,2′,7,7′-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene are considered as the best electron and hole transport layers. Metal oxide materials, either bare or doped with different metals, are stable, cheap, and effective.

太阳能是无限量的可持续燃料，但是太阳能电池的效率是有限的。钙钛矿太阳能电池的效率在短短几年内从3.9％提高到25.5％。与染料敏化太阳能电池，有机太阳能电池以及由硅，GaAs，硒化铜铟镓（CIGS）和CdTe制成的传统太阳能电池相比，钙钛矿太阳能电池实际上被认为是很有前途的。在这里，我们回顾钙钛矿太阳能电池中裸露和掺杂的金属氧化物电子传输层。已经发现，通过调节载流子的提取，运输和重组，电荷转移层对于控制钙钛矿太阳能电池的性能至关重要。电子和空穴传输层均应用于电荷分离和传输。TiO ₂和2,2'，7,7'-四氟[N，N-二（4-甲氧基苯基）氨基] -9,9'-螺二芴被认为是最好的电子和空穴传输层。裸露或掺杂有不同金属的金属氧化物材料稳定，便宜且有效。