有机无机杂化钙钛矿材料具有吸收光谱宽、消光系数高、载流子扩散长度长、非辐射复合几率低等优点，以此类材料为吸光层的钙钛矿太阳能电池（PSCs）光电转换效率（PCE）高、制备简易、成本较低，但湿法制备造成的钙钛矿成膜问题和其自身的化学稳定性问题制约了高效率PSCs的发展。本论文针对湿法制备中钙钛矿薄膜覆盖度低易导致电子空穴反向复合的问题，开展了钙钛矿成膜调控与薄膜覆盖度对载流子传输和PSCs光伏特性影响的研究。针对钙钛矿材料在水氧条件下的降解问题，研究了单一离子钙钛矿材料和混合离子钙钛矿材料降解机制，开展了组分掺杂和界面修饰提高PSCs水氧稳定性的研究。主要研究内容如下：（1）钙钛矿在TiO2表面覆盖不完全易造成TiO2和空穴传输层接触，导致电子空穴发生反向复合。通过调控两步法中的PbI2浓度，提高了钙钛矿在多孔TiO2上的覆盖度，光吸收和光散射作用增强，使得器件光捕获效率提高，同时抑制了电荷反向复合，增强了载流子的传输和收集。通过对钙钛矿覆盖度的调控，显著提升了PSCs光伏特性，尤其是将短路电流密度由15.2 mA cm-2提升至20.6 mA cm-2。（2）甲脒基铅碘(FAPbI3)在水氧条件下存在严重的相变和降解，通过掺杂大尺寸苯乙铵碘盐（PEAI），利用PEAI中苯乙基的空间位阻效应和疏水性质阻碍了水分子对FAPbI3的降解，同时晶格结合能增大，相变势垒提高，抑制了晶格的扭曲和相变。此外，PEAI钝化了钙钛矿表面和晶界中的缺陷态，降低了电子空穴的反向复合。通过优化，器件PCE由14.1%提升至17.7%。未掺杂器件在空气中放置16天后PCE衰减为0，而掺杂后的器件仍保持了90%以上的初始效率，PSCs的水氧稳定性得到显著提升。（3）对混合离子钙钛矿FA1-xCsxPbI3-yBry的水氧稳定性研究表明，其在高湿度条件下易降解产生枝状物CsPbI3。通过在钙钛矿表面修饰PEAI，增大了水分子在其表面的接触角，阻挡了水分子在薄膜表面的吸附及其在薄膜中的渗透。同时PEAI过量的I-补偿了Pb的配位缺失，其对表面缺陷态的钝化作用降低了反向复合，使得器件PCE由13.1%提升至17.1%。未修饰器件在70%RH条件下放置22 h后PCE降为0，而修饰后的器件在100 h后仍保持了初始效率的60%以上，有效提升了混合离子钙钛矿PSCs在高湿度下的稳定性。

Organic–inorganic hybrid perovskites have spurred scientists' great interests due to the wide absorption spectra, high absorption coefficients, long diffusion length and low nonradiative recombination. Perovskite solar cells (PSCs) employ the organic-inorganic hybrid perovskites as the absorber show great advantages for potential application, such as high efficiency, solution processing and low cost. However, the perovskite fabrication process causes undesirable film morphologies with low coverage upon the carrier transporting layer, leading to severe recombination and poor photoelectric conversion efficiency (PCE). Moreover, the decomposition of perovskite under humidity hinders the long-term stability of PSCs. Here, we studied the effect of perovskite coverage on the carrier transport and devices performance by controlling the film formation process. Except chasing high performance, we carefully investigated the degradation mechanism of single-cation perovskites and mixed perovskites, and improved the humidity stability by compositional and interfacial engineering to fabricate high-efficiency and stable PSCs. The main results and conclusions were as follows: (1) The low coverage of the perovskite film on the mesoporous TiO2 film would cause the direct contact of TiO2 and the hole transport layer, leading to severe recombination. By controlling the concentration of PbI2 solutions in the sequential deposition process, the coverage of the perovskite layer on the mesoporous TiO2 film was effectively improved. The increase of the coverage enhanced light absorption and scattering, resulting in enhanced light harvesting. Meanwhile, due to the decreased recombination, the diffusion coefficient was also increased, which facilitated carriers transport and collection. As a result, the PCE of as-fabricated devices was significantly improved, with the photocurrent increased from 15.2 mA cm-2 to 20.6 mA cm-2.(2) Formamidinium lead iodide (FAPbI3) perovskites suffer from serious phase transition from black α-phase FAPbI3 into yellow non-perovskite δ-phase and further decomposition under the ambient condition. Incorporating phenylethylammonium iodide (PEAI) retarded the degradation due to the steric effect and hydrophobicity of the phenrthyl group, which helped prevent moisture from interacting with perovskites. Moreover, PEA+ assembled at the grain boundaries raised the phase transition energy, hindered the lattice distortion and enhanced the phase stability. The PEA+ and its I? counterion also passivated the surface defects of perovskites and improved the device performance from 14.1 to 17.7%. After stored in the ambient air for 16 days, the device still retained 90% of its initial PCE, indicating the improved humidity stability by PEAI incorporation.(3) We unveiled the susceptibility of the mixed perovskites to high-level humidity and provided further understanding for its moisture-induced degradation process. A rapid degradation after several hours’ storage in an environment with a relative humidity (RH) of 70% was indicated by the appearance of CsPbI3 phase along with needle-like morphology. To address this issue, we rationally introduced a feasible interfacial modification with PEAI as a molecular ligand onto the compositional perovskite film. The hydrophobicity of PEA+ increased the contact angle of water on the film surface and hindered the interaction between moisture and perovskites. Excess iodide compensated the absence of iodide at the unsaturated lead atoms, effectively reduced the recombination and enhanced the photovoltaic performance of its derived PSCs (from 13.1 % to 17.1%). Finally, the device with PEAI treatment retained 60% of its initial PCE after kept in 70%RH for 100 h, demonstrating the effectiveness of the PEAI treatment for PSCs’ stability improvement under high-level humidity.