Self‐Polymerization of Monomer and Induced Interactions with Perovskite for Highly Performed and Stable Perovskite Solar Cells

Abstract

While there is promising achievement in terms of the power conversion efficiency (PCE) of perovskite solar cells (PSCs), long-term stability has been considered the main obstacle for their practical application. In this work, the authors demonstrate the small monomer 2-(dimethylamino) ethyl methacrylate (DMAEMA) with unsaturated carboxylic acid ester bond in the antisolvent for perovskite formation to improve the PCE and stability. The results show that DMAEMA is self-polymerized and uniformly distributed in the film, contributing to the improved crystallinity of the perovskites. Equally important, it is found that there are newly established interactions of Pb 2+ and DMAEMA, and iodine and ternary amine between DMAEMA and perovskites, which improves the uniformity of the lead (II) iodide vertical distribution along with the films and thus phase stability, as well as largely decreases defects density in the film. Overall, the inverted PSCs with DMAEMA exhibit a open-circuit voltage of 1.10 V, short-circuit current of 23.86 mA cm −2 , fill factor of 0.82, and finally PCE reaches 21.52%. Meanwhile, the PSC stability is significantly improved due to the inhibition of the formation of iodine, reduction of the uncoordinated Pb 2+ , and suppression of phase segregation.

Recent Advances in Hole-Transporting Layers for Organic Solar Cells

“…Compared with PEDOT:PSS HTLs, CuSCN/AMQSs HTLs were more stable at room temperature, retaining 68% of the initial PCE over 1 month not only in fullerene systems such as PTB7- Th:PC 71 BM, but also in non-fullerene systems. Other strategies involving triple-interface passivation [ 210 ], multifunctional interface layer using lead sulfide quantum dots (QDs) [ 211 ], and self-polymerization of the monomer have been also reported to passivate surface roughness and interface defects [ 212 ]. The surface passivation is key in the construction of OSCs to reduce non-radiative recombination losses which in turns affect the charge separation rate once excitons achieve the donor/acceptor interface, resulting in a low V oc and FF.…”

Macromonomer crosslinking polymerized scaffolds for mechanically robust and flexible perovskite solar cells

“…Previous reports indicated that small molecules containing CC bonds also have the characteristics of cross-linking polymerization. 25,31 The monomers of ethylene glycol dimethacrylamide (EGDMA) are investigated for comparison and the molecular structure is shown in Fig. S2a (ESI†).…”

“…22,23 Therefore, an alternative approach to prepare polymer-regulated PSCs is to add small molecule monomers to perovskite precursor solutions and then trigger the cross-linking polymerization during the thermal annealing of perovskite films. 22–25 For example, Chen et al introduced the polymerizable organic small molecule thioctic acid (TA) into perovskite films to form a continuous polymer (poly(TA)) network after thermal annealing. 22 Yang et al reported a polymerization-assisted grain growth strategy using dimethyl itaconate (DI) monomers to form bulkier polymers.…”

Surface fluoride management for enhanced stability and efficiency of halide perovskite solar cells via a thermal evaporation method

“…Phenethylammonium uoride (PEAF) was simply synthesized by neutralizing equimolar amounts of hydrouoric acid and phenethylamine. The synthesis details are described in the ESI, † and the 1 H and 13 C NMR spectra of the PEAF are presented in Fig. S1.…”

“…Due to the ionic nature of the perovskites and solution deposition approach employed, numerous defects, especially halogen anion and organic cation vacancies, could be formed easily at the surface and grain boundaries of the perovskite lms due to the removal of the organic and halogen components from the lms, leaving behind the uncoordinated Pb 2+ and Pb 0 defects. [12][13][14][15][16] These defects could serve as charge carrier recombination sites and cause nonradiative recombination losses, deteriorating the photovoltaic performance. Moreover, the defects leave the lms susceptible to humidity attack, accelerating the degradation of perovskite devices.…”