钙钛矿太阳能电池电子传输层用SnO_(2)的溶剂热改性研究

Solvothermal Modification of SnO_(2)for Electron Transport Layers of Perovskite Solar Cells

SnO_(2)因具有高光学透过性、高电子迁移率,被作为电子传输材料广泛应用于钙钛矿太阳能电池(Perovskite Solar Cells,PSCs)中,但是溶胶—凝胶法制备的SnO_(2)薄膜,由于制备温度低,获得SnO_(2)薄膜晶粒的结晶性差,薄膜缺陷较多,会导致光电电子的复合,因而光电转化率较低。采用去离子水、甲醇、乙醇和异丙醇处理SnO_(2)电子传输层(Electron Transport Layers,ETLs),研究了水热溶剂热处理对SnO_(2)ETLs和PSCs性能的影响。采用XRD、SEM、接触角、AFM、UV-Vis、J-V曲线和IPCE对样品的物相、形貌、粗糙度、光学性能和光电性能进行表征。结果表明,采用溶剂热处理可以提高SnO_(2)的结晶度,提高薄膜的可见光透射率,增强ETLs与钙钛矿层的界面接触,有效提高电池的光电转换效率(Photoelectric Conversion Efficiency,PCE)。SnO_(2)经水热处理组装的PSCs光电性能最优,PCE为15.48%,比未处理电池的PCE 13.60%高出13.8%。另外,其开路电压(Open-circuit Voltage,V_(oc))为1.09 V,短路电流密度(Short-circuit Current Density,J_(sc))为19.32 mA·cm^(-2),填充因子(Fill Factor,FF)为73.18%。

SnO_(2)has been widely used as an electron transport material in perovskite solar cells(PSCs),due to its high optical transmittance and high electron mobility.However,SnO_(2)films prepared by using sol-gel method have poor crystallinity owing to the low preparation temperature.There are many defects in the films,which led to the recombination of the photoelectrons,thus reducing the photoelectric conversion efficiency(PCE).The SnO_(2)electron transport layers(ETLs)were treated with deionized water,methanol,ethanol and isopropanol.The effects of solvothermal treatments on performance of SnO_(2)ETLs and PSCs were studied.With XRD,SEM,contact angle,AFM,UV-Vis,J-V curves and IPCE,physical phase,morphology,roughness,optical performance and photoelectric performance of the samples were characterized.It is found that hydrothermal and solvothermal treatment can increase crystallinity of SnO_(2)and visible transmittance of the films,thus enhancing the interfacial contact between ETLs and the perovskite layers.As a result,PCE of the PSCs were effectively improved.Photoelectric performance of the PSCs assembled with the hydrothermally treated SnO_(2)was optimized,with the PCE of the cell to be 15.48%,which is 13.8%higher than the PCE(13.60%)of the untreated cell.In addition,the open-circuit voltage(V_(oc))was 1.09 V,the short-circuit current density(J_(sc))was 19.32 mA·cm^(-2),and the fill factor(FF)was 73.18%.