Effects of Organic Cation Additives on the Fast Growth of Perovskite Thin Films for Efficient Planar Heterojunction Solar Cells

Abstract

The film quality of organometallic halide perovskite is very crucial to the performance of planar heterojunction solar cells. Previous methods have generally required a long-time and complex process to control the crystal growth for obtaining a compact and smooth perovskite film. Here, we demonstrate a novel method of growing the high-quality films via a simple and rapid process. Organic cations are used as additives in the solution of CH3NH3PbI3 (MAPbI3), which plays a key role in the film-forming process. These organic cations can enhance the film-forming ability and do not lead to a residue in the film end-product. On the basis of these characteristics, highly efficient perovskite solar cells with a simple planar heterojunction structure were achieved. Because the additives can simplify and accelerate the fabrication process and have no chance to induce any negative effect on the device, they will have a large potential in the production of various high-quality perovskite films and low-cost, large-scale, and high-performance devices.

Hybrid organic–inorganic CH3NH3PbI3perovskite building blocks: Revealing ultra‐strong hydrogen bonding and mulliken inner complexes and their implications in materials design

“…[48] Although this is against common chemical intuition, there are several reports suggesting that the organic cation does/does not do anything for the development of the electronic structure of the CH 3 NH 3 PbI 3 system. [18g,e,22d, [48][49][50][51][52][53][54][55][56][57][58][59][60] For instance, Whalley et al have asserted that "In the static picture (as in the case of an electronic band structure calculated for a single ionic snapshot), MA plays no direct role in optoelectronic properties of the material as the molecular electronic levels lie below that of the inorganic framework . .…”

“….." [50] In contrary, Wang et al have experimentally observed that MA can serve as an additive in the solution of CH 3 NH 3 PbI 3 , which plays a key role in the film-forming process. [52] Salado et al have demonstrated that the organic cation part in the perovskite plays an important role in terms of crystal structure tuning from tetragonal to trigonal or pseudocubic or vice versa depending on the organic cations used, while it also displays different microstructure. [53] In fact, there have been versatile views presented to explain what is the role of the organic cation.…”

Metal–Organic‐Compound‐Modified MoS2 with Enhanced Solubility for High‐Performance Perovskite Solar Cells

“…[32] Am ixture solution with 1mmol CH 3 NH 3 PbI 3 and 0.4 mmol DEACl dissolved in DMF (1 mL) was spin-coating on PEDOT:PSS films with the speed of 4000 rpm and then annealed on ap late for 10 min at temperature of 130 8C. The MAPbI 3 and DEACl mixture solution was deposited on top of the substrates with the PEDOT:PSS layer to the produce perovskite film by the process described in our previous paper.…”

“…The MAPbI 3 and DEACl mixture solution was deposited on top of the substrates with the PEDOT:PSS layer to the produce perovskite film by the process described in our previous paper. [32] Am ixture solution with 1mmol CH 3 NH 3 PbI 3 and 0.4 mmol DEACl dissolved in DMF (1 mL) was spin-coating on PEDOT:PSS films with the speed of 4000 rpm and then annealed on ap late for 10 min at temperature of 130 8C. After the perovskite film was formed, an electronic transfer material (15 mg of PCBM was added into 1mLo fc hlorobenzene) was spin-coated on top of the perovskite film at as peed of 1500 rpm for 30 s. Finally,a1 20 nm Ag was deposited on top of the PCBM layer by at hermal evaporation process in av acuum chamber with ap ressure of less than 10 À4 Pa.…”

“…As is well known,t he perovskite active material is very sensitive to water.H owever,t he hole-transport layer PEDOT:PSS absorbs water extremelye asy,s ow ec onsidered that the can be dispersed MoS 2 -PAS into PEDOT:PSS to increase hydrophobicity.T he perovskite film wasd eposited by the process described in our previous paper [32] and was uniform and compact with at hickness of 350 nm. Figure S4 shows the SEM image of CH 3 NH 3 PbI 3 films deposited on PEDOT:PSS films with and without MoS 2 -PAS.…”