Controlled Crystallization of the Methylammonium Halide Layer in Thin-Film Perovskite Solar Cells

如上所述，为了提高钙钛矿太阳能电池的性能，特别是晶体钙钛矿相的生长，需要改进。这就是本项目提案的目标1。支架设计到目前为止，用于制造用于光伏能量转换的结构化薄膜的大多数多孔支架层都是基于相互连接的颗粒状颗粒，这限制了所生成薄膜的孔隙率的控制。颗粒基薄膜中的特定空穴(气孔)的尺寸通常很小，并且分布很广。为了增加孔径，必须使用较大的颗粒，这同时会降低效率。因此，有序介孔支架(通过溶胶凝胶法或纳米铸造法合成，细节在工作计划中说明)具有在固定壁厚的情况下具有更大的孔的优点。较大的孔径将允许更大(但仍然受限)的钙钛矿晶体具有较少的晶界，在那里可能发生电荷复合。因此，该项目的目标是孔径在5纳米到100纳米之间。这种纳米多孔支架的优点在于孔径分布窄，这有利于颗粒基薄膜的制备。2.钙钛矿层的结晶度和微晶尺寸对器件性能的影响沉积均匀的钙钛矿层是制备高效、可重复性PSCs的关键挑战之一。纳米多孔支架层(如上所述)有助于更好地控制结晶过程。钙钛矿太阳能电池中的电荷传输和复合阐明钙钛矿太阳能电池中的电荷传输和复合对于开发高效器件至关重要，即通过调节钙钛矿晶体尺寸(见目标2.1)或通过开发和实施新型电荷选择接触。这种对结构薄膜能级(能带结构)的调整提高了钙钛矿型太阳能电池的性能，旨在最大限度地减少接触处的复合并提取电荷。因此，有必要弄清楚器件内的漂移长度和载流子迁移率。这些参数可以通过线性升高电压(CELIV)测量的电荷载流子提取来确定。

To boost the performance of perovskite solar cells, especially the growth of the crystalline perovskite phase needs to be improved, as stated above. This is the objective of this project proposal.1. Scaffold designTo date most of the porous scaffold layers that are used for the fabrication of structured films for photovoltaic energy conversion are based on interconnected, granular particles, which limits the control of the porosity of the generated film. The size of the inter-particular voids (pores) in particle-based films is generally quite small and exhibits a broad distribution. To increase the pore size it is necessary to use larger particles, which at the same time decreases the efficiency. Therefore, ordered mesoporous scaffolds (synthesized by the sol-gel method or by nanocasting, details are stated in the work plan) bear the advantage of larger pores at constant wall thickness. A larger pore size will allow for larger (yet still confined) perovskite crystals with fewer grain boundaries where charge recombination can occur. Therefore the project aims at a pore size between 5 nm and 100 nm. The advantage of such a nanoporous scaffold lies in the narrow distribution of pore sizes, which is advantageous to particle-based films. 2. Influence of the crystallization and crystallite size of the perovskite-containing layer on the performance of the deviceThe deposition of a uniform perovskite-containing layer is one of the key challenges in the preparation of efficient and reproducible PSCs. A nanoporous scaffold layer (as stated above) facilitates better control of the crystallization process.3. Charge transport and recombination in perovskite solar cellsClarifying the charge transport and recombination in perovskite solar cells is of paramount importance in developing efficient devices, i.e. by tuning the perovskite crystal size (see Objective 2.1) or by developing and implementing novel charge-selective contacts. This adjustment of the energy levels (band structure) of the structured films increases the performance of the perovskite solar cells, aiming to minimize the recombination at the contacts and to extract charges. Therefore, it is necessary to clarify the drift length and charge carrier mobility within the device. These parameters can be determined by charge carrier extraction by linearly increasing voltage (CELIV measurements.