氧掺杂石墨相氮化碳改性钙钛矿薄膜的制备和性能

Oxygen-doped graphitic phase carbon nitride-modified perovskite films

摘要:

钙钛矿薄膜表面和晶界处通常存在大量缺陷,诱导光生载流子的非辐射复合,严重抑制了光伏器件的光电性能。采用氧掺杂石墨相氮化碳(g-C3N4-O)作为界面修饰层添加到钙钛矿太阳能电池(PSCs)中。钙钛矿薄膜改性后(110)面优先取向,高光电性能的(110)面的结晶度从75.11°提高到了78.62°,半峰宽减少了37.73%；薄膜表面更加平整、均匀致密和无针孔；界面荧光寿命Tave减少了32.51%,电荷传输和提取能力显著增加。同时通过XPS证明了g-C3N4-O中的N原子与钙钛矿薄膜中的欠配位的Pb离子结合成键,有效钝化了钙钛矿薄膜界面处深能级缺陷,改善了钙钛矿薄膜界面处电荷传输和提取。

Abstract:

Perovskite thin films often have numerous defects on their surface and at their grain boundaries. These defects can lead to nonradiative complexation of photogenerated carriers, which can significantly reduce the photovoltaic performance of photovoltaic devices. Oxygen-doped graphite-phase carbon nitride (g-C3N4-O) was utilized as an interfacial modification layer in perovskite solar cells (PSCs). The modification of the perovskite films resulted in preferential orientation of the (110) facets. The crystallinity of the (110) facets with high photovoltaic performance increased from 75.11° to 78.62°, and the half-peak width decreased by 37.73%. The film surface is now flatter, more uniformly dense, and free of pinholes. The interfacial fluorescence lifetime has been reduced by 32.51%, and the charge transport and extraction capacity have significantly increased. XPS demonstrated that the N atoms in g-C3N4-O bonded with the under-coordinated Pb ions in the perovskite films, passivating the deep energy level defects at the interface and improving charge transport and extraction.