Novel insights into the role of solvent environment in perovskite solar cells prepared by two-step sequential deposition

Interior/Interface Modification of Textured Perovskite for Enhanced Photovoltaic Outputs of Planar Solar Cells by an In Situ Growth Passivation Technology

“…The narrowing of the energy gap further confirms that DMF can induce the substitutional doping of FA + cations while constructing the texture configuration of the absorbers, which has a positive effect on broadening the spectral response range of perovskite and further enhancing the light trapping ability of solar cells. 8,20 Although the PVK-D45 sample has excellent optical properties, its relatively poor film quality (see Figure 1d, SEM) and weak crystallinity (see Figure 1e, XRD) cause a serious carrier recombination, thus reducing the photovoltaic performance output of the device. 39 From the corresponding XRD patterns in Figure 1e, the crystallinity of the textured perovskite gradually decreases with the increase in DMF content.…”

“…This indicates that IPA induced the larger FA + cation (2.79 Å) to replace the smaller MA + cation (2.70 Å) into the perovskite lattice, promoting lattice expansion and effectively improving crystallinity. 8 With the increase in DMF content, as shown in Figure 1a-d, the texture morphologies of the corresponding samples gradually deepened, which is mainly attributed to the accelerated dissolution of the control perovskite by the strongly polar DMF and rapid evaporation of some organic cations (FA + and/or MA + ions) carried by DMF during molecular exchange, which corrodes the traditional planar perovskite into a random texture structure. 30 Therefore, excessive DMF (45 μL) excessively corrodes the absorber, resulting in an incomplete perovskite coverage and leakage current, which ultimately degrades device performance.…”

“…5,6 Compared to mesoporous PSCs, planar heterojunction PSCs have been actively used in flexible, ultrathin, and tandem solar cells due to their relatively simple device structures and low-temperature synthesis processes, which lead to broader commercial application prospects and research value. 7,8 However, owing to the lack of mesoporous charge transporting layers, thinner perovskite absorbers cannot fully absorb the incident light, resulting in serious optical losses. 9,10 Therefore, a series of strategies have been developed to compensate for the inherent optical losses of planar devices, such as the introduction of scattering media, 11,12 use of antireflective layers on the light-incident side, 13 and/or deposition of textured charge-transporting layers or perovskite absorbers.…”

“…Organic–inorganic hybrid perovskite solar cells (PSCs) have been considered as the most promising photovoltaic technology because of their low-cost manufacturing, remarkable photoelectric properties, and excellent power conversion efficiency (PCE). − Currently, their certified PCE has reached 25.5%, which makes them a promising alternative to single-crystalline silicon- and CdTe-based commercial solar cells in the near future. , Compared to mesoporous PSCs, planar heterojunction PSCs have been actively used in flexible, ultrathin, and tandem solar cells due to their relatively simple device structures and low-temperature synthesis processes, which lead to broader commercial application prospects and research value. , However, owing to the lack of mesoporous charge transporting layers, thinner perovskite absorbers cannot fully absorb the incident light, resulting in serious optical losses. , Therefore, a series of strategies have been developed to compensate for the inherent optical losses of planar devices, such as the introduction of scattering media, , use of antireflective layers on the light-incident side, and/or deposition of textured charge-transporting layers or perovskite absorbers. , …”

Zwitterionic Ionic Liquid Confer Defect Tolerance, High Conductivity, and Hydrophobicity toward Efficient Perovskite Solar Cells Exceeding 22% Efficiency

“…[3,7,8] Several methods have been reported to prepare high-quality perovskite films, including thermal evaporation, twostep sequential deposition, vapor-assisted solution processing, and one-step spincoating method. [9] Although the simple, antisolvent-free, low-toxic, and time-consuming two-step method has been widely used in most of the high-efficiency PSCs with certified PCE exceeding 24%, [10][11][12] the quickly transformed perovskite often exhibit poor surface coverage with pinholes and high surface roughness, [13] which is related to the rapid reaction between the PbI 2 and the organic component (FAI, MABr, MACl, etc.). [14] More importantly, the polycrystalline perovskite usually contains a large number of structural disorders [15] and surface defects, [16] inducing severe degradation of photovoltaic performance.…”