Department of Electrical and Electronic Engineering, The University of Hong Kong , Pok Fu Lam Road, Hong Kong, China.
ACS Nano. 2015 Jan 27;9(1):639-46. doi: 10.1021/nn505978r. Epub 2015 Jan 2.
Solar cells incorporating lead halide-based perovskite absorbers can exhibit impressive power conversion efficiencies (PCEs), recently surpassing 15%. Despite rapid developments, achieving precise control over the morphologies of the perovskite films (minimizing pore formation) and enhanced stability and reproducibility of the devices remain challenging, both of which are necessary for further advancements. Here we demonstrate vacuum-assisted thermal annealing as an effective means for controlling the composition and morphology of the CH(3)NH(3)PbI(3) films formed from the precursors of PbCl(2) and CH(3)NH(3)I. We identify the critical role played by the byproduct of CH(3)NH(3)Cl on the formation and the photovoltaic performance of the perovskite film. By completely removing the byproduct through our vacuum-assisted thermal annealing approach, we are able to produce pure, pore-free planar CH(3)NH(3)PbI(3) films with high PCE reaching 14.5% in solar cell device. Importantly, the removal of CH(3)NH(3)Cl significantly improves the device stability and reproducibility with a standard deviation of only 0.92% in PCE as well as strongly reducing the photocurrent hysteresis.
钙钛矿太阳能电池采用卤化铅基钙钛矿吸收体，可以展现出令人瞩目的功率转换效率（PCE），最近已经超过 15%。尽管发展迅速，但要实现对钙钛矿薄膜形态（最小化孔隙形成）的精确控制，以及提高器件的稳定性和重现性，仍然具有挑战性，这两者对于进一步的发展都是必要的。在这里，我们展示了真空辅助热退火作为一种有效手段，可以控制由 PbCl2 和 CH3NH3I 前体制备的 CH(3)NH(3)PbI(3) 薄膜的组成和形态。我们确定了 CH(3)NH(3)Cl 副产物在钙钛矿薄膜形成和光伏性能中所起的关键作用。通过我们的真空辅助热退火方法完全去除副产物，我们能够生产出纯净、无孔的平面 CH(3)NH(3)PbI(3)薄膜，其太阳能电池器件的功率转换效率达到 14.5%。重要的是，去除 CH(3)NH(3)Cl 显著提高了器件的稳定性和重现性，其功率转换效率的标准偏差仅为 0.92%，并且强烈减少了光电流滞后。
