通过调控薄膜生长衬底温度,提出了一种改良的蒸汽辅助沉积法制各有机一无机混合钙钛矿薄膜,可以更为可控优化薄膜生长条件。用同步辐射掠入射X射线衍射(Grazing Incidence X.ray Diffraction,GIXRD)结合扫描电镜(Scanning Electron Microscope,SEM)、紫外可见吸收谱(try-Visible Absorption Spectrum)等表征方法证明衬底温度对制备的钙钛矿薄膜质量具有重要的作用较低的衬底温度(约70℃)有助于钙钛矿晶粒的形成,其结晶性、晶面择优生长取向均较好,同时具有较高的光吸收性能;当衬底温度升高时(100℃、125℃),所制备的钙钛矿薄膜结晶性变弱,晶体择优生长取向明显变差,光吸收性能随之下降。研究结果有助于进一步优化蒸汽辅助沉积法制备钙钛矿薄膜工艺。
Background: The crystallinity and morphology ofperovskite thin film have decisive roles on its device performance in the perovskite solar cells. The perovskite thin film can be prepared using a vapor-assisted solution process, which needs to be thoroughly investigated to improve its crystallinity and morphology. Purpose: We attempt to study the influence of the substrate temperature on the crystallinity and morphology of perovskite thin film prepared using the vapor-assisted solution process. Methods: The perovskite thin films were prepared using a modified vapor-assisted solution process with different substrate temperatures, which were characterized by grazing incidence X-ray diffraction (GIXRD), UV-visible absorption spectrum, and scanning electron microscope (SEM).Results: GIXRD analysis shows that the perovskite thin film prepared via the vapor-assisted solution process with a low substrate temperature of 70 ℃ exhibits favorite crystallinity with better preferential crystalline orientation than those prepared at higher temperatures (100 ℃ and 125 ℃). UV-Visible absorption spectra show the optical absorption intensity of perovskite thin film prepared with a low substrate temperature of 70 ℃ is the largest. SEM results support the GIXRD results, which show the perovskite crystal size and the film morphology change dramatically with increasing substrate temperature. Conclusion: Based on the above results, the crystallinity, morphology and the optical absorption of perovskite thin film prepared using the modified vapor-assisted solution process are sensitive to the substrate temperature during the preparation. In general, a low substrate temperature in the modified vapor-assisted solution process is more desirable to prepare perovskite films with good crystallinity and hieh ottical absorotion.