复合钙钛矿太阳能电池电荷传输层材料研究进展

A Review on Charge Carriers Transport Materials Used in Organometal Halide Perovskite-based Solar Cells

有机无机复合钙钛矿太阳能电池因具有适合的载流子扩散长度而成为备受关注的有望获得高效率的光伏器件。复合钙钛矿材料本身不含贵金属元素,可以采用液相法或物理气相法低温制备,成本低廉,但目前应用最多的电子传输层材料TiO2需400~500℃煅烧,与柔性基底及低温制备技术适应性差;空穴传输层材料SpiroOMeTAD合成工艺复杂,价格高昂,限制了复合钙钛矿太阳能电池的开发应用。开发和研究导电性好、成本低、稳定性好的电子和空穴传输层材料是复合钙钛矿太阳能电池研究中的一个非常重要的方面。综述了复合钙钛矿太阳能电池中电荷传输层材料的研究进展及发展方向。电子传输层材料方面通过对TiO2的改性以及与石墨烯的复合,采用ZnO、石墨烯或PCBM作为电子传输层材料,以与柔性基底及低温制备技术相适应。空穴传输层材料方面,采用其它低成本、导电性高的有机p型半导体替代spiro-OMeTAD;采用无机空穴传输层材料以避免有机空穴传输层材料的老化问题,提高电池的长期稳定性;利用复合钙钛矿材料兼作吸收层与空穴传输层,制备无空穴传输层材料结构电池以降低成本,提高稳定性。

The organometal halide perovskite-based solar cells have attracted considerable attention as a promising highly efficient device because of its suitable band gap and great charge carrier diffusion length.Besides the high PCE,organo-metal halide perovskite does not contain noble elements and can be fabricated by solution process or physical vapor deposition at a low temperature,which affords the potential cost-effective products.However,the most widely used electron transport material to date in organometal halide perovskite-based solar cells,i.e.TiO2,need to be annealed at 400-500 ℃ to achieve sufficient electron conductivity.The hole transport material spiroOMeTAD is very expensive due to its complex fabrication process.Herein,charge carrier materials used in organometal halide perovskite-based solar cells are surveyed.With the aim to optimize the cell structure,improve the PCE,decrease the cost,and adapt to flexible substrate and low-temperature fabrication processes,substantial research has been focused on developing stable low-cost charge carrier transport materials with suitable band gap,high charge-carrier mobility and conductivity.Modified TiO2,TiO2/graphene composite,ZnO,graphene and PCBM are selected to replace conventional TiO2 as the electron transport materials to adapt with the flexible substrates and the low-temperature solution processes.For the hole transport materials,new easily fabricated,less expensive organic p-type semiconductors with high hole mobility and conductivity are developed to replace spiro-OMeTAD and achieve high PCE.Inorganic p-type semiconductors exhibiting high hole mobility,long-term stability and low cost are employed to eliminate the aging issue of organic hole transport materials and contribute to the durability of the cells.The organometal halide perovskites themselves exhibit high hole conductivity and could serve as both absorber and hole transport material to fabricate hole-conductor-free perovskite solar cells with good stability and low cost.