Controllable Grain Morphology of Perovskite Absorber Film by Molecular Self-Assembly toward Efficient Solar Cell Exceeding 17%

Abstract

The highly developed crystallization process with respect to perovskite thin films is favorable for efficient solar cells. Here, an innovative intermolecular self-assembly approach was employed to retard the crystallization of PbI2 in dimethylformamide (DMF) by additional solvent of dimethyl sulfoxide (DMSO), which was proved to be capable of coordinating with PbI2 by coordinate covalent bond. The obtained PbI2(DMSO)x (0 ≤ x ≤ 1.86) complexes tend to be closely packed by means of intermolecular self-assembly. Afterward, an intramolecular exchange of DMSO with CH3NH3I (MAI) enabled the complexes to deform their shape and finally to reorganize to be an ultraflat and dense thin film of CH3NH3PbI3. The controllable grain morphology of perovskite thin film allows obtaining a power conversion efficiency (PCE) above 17% and a stabilized power output above 16% within 240 s by controlling DMSO species in the complex-precursor system (CPS). The present study gives a reproductive and facile strategy toward high quality of perovskite thin films and efficient solar cells.

Rational design of SnO2-based electron transport layer in mesoscopic perovskite solar cells: more kinetically favorable than traditional double-layer architecture

“…It is worth noting that in this section, the photovoltaic performance of M-PSCs has been improved a lot through optimizing the deposition of CH 3 NH 3 PbI 3 by DMSO-assistant "two-step" route as reported previously (Fig. S1, Supplementary information) [35] higher PCE is selected for comparison with conventional TiO 2 underlayer with an optimized thickness of~60 nm. Table 3 shows the average photovoltaic parameters obtained from 60-70 devices for each group of M-PSCs.…”

New insight into solvent engineering technology from evolution of intermediates via one-step spin-coating approach

“…This mechanism could help us to understand the impact of intermediate phases on perovskite crystal growth. Namely, the crystallinity of intermediate phases is a crucial parameter on perovskite films [26,27]. The diffraction peak intensity of the MAI-PbI2-DMSO is much higher than that of MAI-PbI2-DMF intermediate phases.…”

Function Follows Form: Correlation between the Growth and Local Emission of Perovskite Structures and the Performance of Solar Cells

“…[34] Previously, it has been reported that DMSO solvent has a tendency to form an adduct with lead iodide and while employing such adducts, the fabrication of high-efficiency solar cells was reported. [12,35,36,37,38] Under standard illumination, devices based on CH(NH 2 ) 2 PbBr 3 films prepared when a single solvent (DMF) was used for the deposition of PbBr 2 , yielded a V OC of 1140 mV, ( [ 34] SEM analysis reveals the formation of elongated CH(NH 2 ) 2 PbBr 3 structures (Figure 5a) from PbBr 2 (DMF) solution, whereas smooth and uniform CH(NH 2 ) 2 PbBr 3 films ( Figure 5b) were obtained from PbBr 2 (DMF+DMSO) solution. We further evaluated the role of solvent on the emission characteristics of CH(NH 2 ) 2 PbBr 3 films using room temperature CL.…”