氨基甲酸乙酯界面修饰对钙钛矿太阳能电池性能影响

Effect of ethyl carbamate interface modification on performance of perovskite solar cells

虽然有机无机杂化钙钛矿材料因其优异的光电性能而在光伏领域崭露头角,但溶液法制备过程中无可避免产生的界面缺陷会导致界面处发生载流子非辐射复合而造成载流子损失,同时,水分和氧气经界面缺陷部位渗入钙钛矿层中也会对器件的长期稳定性造成不利影响。研究表明,钙钛矿薄膜的界面修饰具有缺陷态钝化、能级调节等作用,是改善电池光电性能的有效手段。基于此,本文在钙钛矿薄膜与空穴传输层(HTL)之间引入氨基甲酸乙酯(EU)钝化层,其官能团C==O与—NH_(2)作为路易斯碱可以与钙钛矿晶体中未配位的Pb^(2+)产生键合作用,从而抑制载流子与晶界处的缺陷复合。最终,在全空气环境下制备的n-i-p型平板结构钙钛矿太阳能电池经EU优化后的光电转换效率(PCE)由初始的17.23%提升至19.51%,在湿度约为40%的空气环境下放置35天仍能保持85%的初始PCE,具有优异的湿度稳定性。

Although organic and inorganic hybrid perovskite materials are prominent in the photovoltaic field due to their excellent photoelectric properties,the interface defects inevitably produced in the process of the solution preparation could lead to the non-radiative recombination of the carriers at the interface,resulting in the loss of the carriers.At the same time,the infiltration of water and oxygen into the perovskite layer through the interface defects could also adversely affect the long-term stability of the device.The results show that the interface modification of perovskite film could passivate the defect state and adjust the energy level,which is an effective means to improve the photoelectric performance of the cells.Based on this,this paper introduced the ethyl carbamate(EU)passivation layer between the perovskite film and the hole transport layer(HTL),and the functional groups C==O and—NH_(2) as Lewis bases could bond with the uncoordinated Pb^(2+)in the perovskite crystals,thus inhibiting the defect recombination between the carriers and grain boundaries.Finally,the photovoltaic conversion efficiency(PCE)of n-i-p type perovskite solar cells prepared in all-air environment increased from the initial 17.23%to 19.51%after EU optimization,and the initial PCE of 85%could still be maintained in the air environment with humidity of about 40%for 35 days,which demonstrating excellent humidity stability.