Two-step processed efficient perovskite solar cells via improving perovskite/PTAA interface using solvent engineering in PbI₂ precursor*

Abstract

The morphology and interface of perovskite film are very important for the performance of perovskite solar cells (PSCs). The quality of perovskite film, fabricated via two-step spin-coating process, is significantly influenced by the morphology and crystallinity of PbI2 film. With the addition of additive dimethyl sulfoxide (DMSO) into the PbI2 precursor, the roughness and trap-state density of perovskite film have been significantly reduced, leading to the excellent contact between perovskite layer and subsequent deposited carrier transport layer. Accordingly, the planar heterojunction PSCs with an architecture of ITO/SnO2/perovskite/PTAA/Ag show an efficiency up to 19.02%. Furthermore, PSCs exhibit promising stability in air with a humidity of ∼ 45%, and retain 80% of initial efficiency after being exposed to air for 400 h without any encapsulation.

Effect of 2-propanol Immersing on Organohalide Perovskite Layer in Perovskite Solar Cells Fabricated by Two-step Method

“…The PbI2 layer fabricated from only DMF solvent is low-crystalline. This result is inconsistent with the previous reports [19][20][21]. The boiling point of DMF, 153℃ is lower than that of DMSO, 189℃.…”

“…The device performance of the 0 vol% specimen is the best of five specimens. As reported in the previous papers [18][19][20][21], when the perovskite layer converted from the lowcrystalline PbI2 is used, the device performance is improved. We compared our fabrication process with the previous fabrication processes.…”

“…reported that the PbI2 layer fabricated from dimethyl sulfoxide (DMSO) solution is amorphous [18]. Other paper also reported the similar result [19][20][21]. The high-quality perovskite layer without a resultant PbI2 layer can be converted from the amorphous PbI2 layer.…”

Flexible Perovskite Solar Cells: From Materials and Device Architectures to Applications

“…Several reports have demonstrated that there is high trap density at the interfaces of PSCs. − Interfacial passivation is an effective way to enhance the performance of PSCs. − However, due to the rougher surface of perovskite on the flexible substrate, the classic organic salt surface passivation strategy cannot seem to achieve desired results. Two-dimensional (2D) perovskite is an applicable interfacial passivation material, which has unexceptionable stability and water-tolerant properties. − Assembling 2D perovskite onto 3D perovskite forming a 2D/3D perovskite heterojunction to improve the interfacial condition is an effective strategy to achieve high-performance and stable PSCs. − More importantly, rough and loose surfaces of perovskite on the flexible substrate are beneficial for the reaction between residual PbI 2 and organic salt to form 2D perovskite.…”

Revealing the microstructure evolution of inorganic CsPbI2Br perovskite via synchrotron radiation grazing incidence X‐ray diffraction

“…[9][10][11] It is well known that post-thermal-annealing plays a key role in the formation of high-quality perovskite films, directly determining the photovoltaic performance of PSCs. [12][13][14][15] It mainly has three main objectives: (i) removing residual solvents after solution processing; (ii) promoting conversion from precursors to perovskite; (iii) increasing crystallinity and promoting the growth of perovskite crystal grains. [16][17][18][19][20] The post-annealing parameters, including temperature, duration and atmosphere, have critical effects on the crystallization, morphology of perovskite film and device performance.…”