Solvent Engineering Using a Volatile Solid for Highly Efficient and Stable Perovskite Solar Cells

Abstract

A strategy for efficaciously regulating perovskite crystallinity is proposed by using a volatile solid glycolic acid (HOCH2COOH, GA) in an FA0.85MA0.15PbI3 (FA: HC(NH2)2; MA: CH3NH3) perovskite precursor solution that is different from the common additive approach. Accompanied with the first dimethyl sulfoxide sublimation process, the subsequent sublimation of GA before 150 °C in the FA0.85MA0.15PbI3 perovskite film can artfully regulate the perovskite crystallinity without any residual after annealing. The improved film formation upon GA modification induced by the strong interaction between GA and Pb2+ delivers a champion power conversion efficiency (PCE) as high as 21.32%. In order to investigate the role of volatility in perovskite solar cells (PSCs), nonvolatile thioglycolic acid (HSCH2COOH, TGA) with a similar structure to GA is utilized as an additive reference. Large perovskite grains are obtained by TGA modification but with obvious pinholes, which directly leads to an increased defect density accompanied by a decline in PCE. Encouragingly, the champion PCE achieved for GA‐based PSC device (21.32%) is almost 13% or 20% higher than those of the control device or TGA‐based device. In addition, GA‐modified PSCs exhibit the best stability in light‐, thermal‐, and humidity‐based tests due to the improved film formation.

Hybrid perovskite crystallization from binary solvent mixtures: interplay of evaporation rate and binding strength of solvents

“…9 Spin-coated perovskite devices with the highest PCEs often employ precursor solutions with a complex solvent combination and various quenching approaches that have been developed empirically. 1,10,11 Adaptation of these approaches to large-scale deposition techniques typically does not yield the desired result; as, for instance, quenching becomes technologically difficult at large scale. 12,13 Therefore, rationalized usage of solvent blends is required to control material crystallization to obtain homogeneous high-quality materials.…”

Fluorinated Black Phosphorene Nanosheets with Robust Ambient Stability for Efficient and Stable Perovskite Solar Cells

“…The above findings strongly indicate the interaction of MA + /FA + with F − . [24e, 27,28] The hydrogen bonds of NH•••F were also confirmed by fourier transform infrared spectroscopy shift of the NH vibration (≈3400-3250 cm −1 ) toward a lower wavenumber for perovskite/F-BP film compared to the pristine perovskite film and perovskite/BP film (Figure S17a, Supporting Information). As shown in Figure S17b, Supporting Information, perovskite/F-BP has a lower N 1s binding energy than perovskite/BP and pristine perovskite, which could also be attributed to the formation of hydrogen bonds.…”

Design of Chemically Stable Organic Perovskite Quantum Dots for Micropatterned Light‐Emitting Diodes through Kinetic Control of a Cross‐Linkable Ligand System

“…However, their volatility prevents a consistent improvement in the optoelectronic properties as well as chemical and optoelectronic stabilities of perovskite QDs with time. [ 22 ] On the other hand, the introduction of a multiple‐bond functional group (C≡C) in the passivation ligand dramatically increases the boiling point and reduces the vapor pressure, leading to long‐term stability, compared to that achieved with short alkanoic acids (C−C). The introduction of a multiple‐bond functional group is also appropriate when the subsequent chemical reaction is considered.…”