Chen Haining, Wei Zhanhua, Yan Keyou, Yi Ya, Wang Jiannong, Yang Shihe
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
Faraday Discuss. 2014;176:271-86. doi: 10.1039/c4fd00155a. Epub 2014 Nov 14.
Hybrid organic/inorganic perovskite solar cells are attracting intense attention and further developments largely hinge on understanding the fundamental issues involved in the cell operation. In this paper, a liquid phase deposition (LPD) method is developed to design and grow a TiO(2) nanolayer at room temperature for carbon-based perovskite solar cells. The TiO(2) nanolayer grown on FTO glass is compact but polycrystalline consisting of tiny anatase TiO(2) nanocrystals intimately stacked together. By directly exploiting this TiO(2) nanolayer in a solar cell of TiO(2) nanolayer/CH(3)NH(3)PbI(3)/nanocarbon, we have achieved a Voc as high as 1.07 V, the highest value reported so far for hole transporter-free CH(3)NH(3)PbI(3) solar cells. This is rationalized by the slower electron injection and longer electron lifetime due to the TiO(2) nanolayer, which enhances the electron accumulation in CH(3)NH(3)PbI(3) and consequently the Voc. By employing a rutile TiO(2) nanorod (NR) array as a base structure for the LPD-TiO(2) nanolayer to support the CH(3)NH(3)PbI(3) layer, the photocurrent density is considerably increased without obviously compromising the Voc (1.01 V). As a result, the power conversion efficiency is boosted from 3.67% to 8.61%. More elaborate engineering of the TiO(2) nanolayer by LPD in conjunction with judicious interfacing with other components has the potential to achieve higher performances for this type of solar cell.
有机/无机杂化钙钛矿太阳能电池正吸引着广泛关注，其进一步发展在很大程度上取决于对电池运行中基本问题的理解。本文开发了一种液相沉积（LPD）方法，用于在室温下为碳基钙钛矿太阳能电池设计并生长TiO₂纳米层。在FTO玻璃上生长的TiO₂纳米层致密但为多晶结构，由紧密堆叠在一起的微小锐钛矿TiO₂纳米晶体组成。通过在TiO₂纳米层/CH₃NH₃PbI₃/纳米碳太阳能电池中直接利用这种TiO₂纳米层，我们实现了高达1.07 V的开路电压，这是迄今为止无空穴传输体的CH₃NH₃PbI₃太阳能电池所报道的最高值。这是由于TiO₂纳米层导致电子注入较慢和电子寿命较长，从而增强了CH₃NH₃PbI₃中的电子积累，进而提高了开路电压。通过采用金红石TiO₂纳米棒（NR）阵列作为LPD-TiO₂纳米层的基础结构来支撑CH₃NH₃PbI₃层，光电流密度显著增加，同时开路电压没有明显降低（1.01 V）。结果，功率转换效率从3.67%提高到了8.61%。通过LPD对TiO₂纳米层进行更精细的工程设计，并与其他组件进行明智的界面结合，有可能实现这类太阳能电池的更高性能。
