Radical Molecular Modulator for High-Performance Perovskite Solar Cells

Abstract

The long-term stability of perovskite solar cells (PSCs) remains an issue impeding their commercialization. Generally, polycrystalline perovskite thin films have many defects on the grain boundaries, which affect the optoelectronic performance and stability of the devices under moisture, heat, illumination, and the presence of an electric field condition. The O-donor Lewis base is often employed to regulate the performance of PSCs such as carbonyl and carboxyl compounds. Herein, we have developed a concept of radical molecular modulation using the O-donor group for high-performance perovskite photovoltaic devices. The judiciously designed radical modulators 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), which located at the perovskite grain boundary through interaction with the perovskite surface sites, effectively passivated the surface defects while templating the formation of large grain crystal and high-quality perovskite thin films. Accordingly, the optimized TEMPO-modulated PSCs achieved a power conversion efficiency of 20.73% with superior stability. This work makes an important contribution for exploring the effect of radical in perovskites to improve the performance of PSCs and other optoelectronic devices.

Benzophenone: A Small Molecule Additive for Enhanced Performance and Stability of Inverted Perovskite Solar Cells

“…This bond was shifted to ∼1650 cm –1 after adding BP into perovskite, which indicates the coordination interaction between BP and Pb 2+ . , Additionally, an absorption peak at 1712 cm –1 is assigned for the stretch vibration of the CN bond in the FA + cation. The CN peak is shifted toward higher wavenumber at ∼1726 cm –1 which is another representation of the interaction between FA + cation in perovskite and the CO bond in BP …”

“…The C�N peak is shifted toward higher wavenumber at ∼1726 cm −1 which is another representation of the interaction between FA + cation in perovskite and the C�O bond in BP. 40 The mechanism of the interaction between BP and FAPbI 3 is shown in Figure 5b. Two mechanisms of bonding between BP and FAPbI 3 are possible based on FTIR spectra.…”

Reduced trap-density and boosted performance of CH3NH3PbI3 solar cells by 1-Pentanethiol enhanced anti-solvent washing route

“…Figure 3(b). showed that emission wavelength around 770 nm with a grander intensity for 1-Pentanethiol incorporated perovskite layers, signifying suppressed non-radiative recombination and thus responsible defects and trap-states [26,38,[58][59][60][61].…”

Redox: Organic Robust Radicals and Their Polymers for Energy Conversion/Storage Devices

“…Triphenylamine derivatives are one of the materials most frequently used as hole-transporting layers. ,, TEMPO cations have been mixed with triphenylamines as oxidants (Figure ). − The oxygen-scavenging properties of radical polymers helped to protect perovskite layers from degradation by oxygen. − …”