Efficient and Stable Perovskite Solar Cells Using Bathocuproine Bilateral-Modified Perovskite Layers

Abstract

Surface modification engineering is an effective method to improve the crystallinity and passivate the perovskite interface and grain boundary, which can improve the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). The typical interface modification method is usually introduced at the interface of the perovskite/hole transport layer (HTL) or perovskite/electron transport layer (ETL) through coordination of the groups in the material with the perovskite. In this work, the n-type semiconductor bathocuproine (BCP) including the pyridine nitrogen bond was modified at the interfaces of perovskite/HTL or perovskite/ETL to improve perovskite crystallinity and interface contact properties. The better crystallinity and superior interface contact properties are obtained using BCP unilateral modification, which obviously increases the PCEs of PSCs. The BCP bilateral modification at both perovskite/ETL and perovskite/HTL interfaces can further improve the crystallinity with fewer defects and superior contact properties, which show the largest V oc (1.14 V) and fill factors (FF 77.1%) compared to PSCs with BCP unilateral modification. PSCs with BCP bilateral modification obtained 20.6% PCEs, which is greatly higher than that (17.5%) of the original PSCs. The stability of PSCs with BCP bilateral modification can be greatly improved due to the better crystal quality and hydrophobic property of the interfaces. The results demonstrated that the n-type BCP material can efficiently modify both perovskite/HTL and perovskite/ETL interfaces beyond its semiconductor type, which can greatly improve the PCEs and stability of PSCs because BCP modification can passivate interfaces, improve interface contact and hydrophobic properties, promote crystallinity of the perovskite layer with fewer defects, and block carrier recombination at both interfaces.

Alkali Metal Fluoride-Modified Tin Oxide for n–i–p Planar Perovskite Solar Cells

“…The integral J SC of the PSC based on SnO 2 ETLs modified with 3 mg•mL −1 CsF is 23.08 mA•cm −2 , which is consistent with the results shown in the J−V curves. 53 In addition, the PCE histogram obviously shows, compared with the PCE of the pristine PSCs (Figure 5c), the narrower PCE distribution of PSCs modified with MF, indicating good reproducibility after introduction of alkali metal fluoride.…”

Monodisperse Carbon Nitride Nanosheets as Multifunctional Additives for Efficient and Durable Perovskite Solar Cells

“…The VBM and conduction band minimum (CBM) of PTI-30 are nearly identical to the reference film; however, PTI causes the shift of WF by 100 meV toward the vacuum level ( E vac ), while E F shifted by 120 meV toward the CBM. This indicates that the PTI-30 films become more n-type, which is likely due to the change of the surface termination in the presence of PTI. − Considering the band structure of PTI (Figures S6 and S10), it serves as a hole blocking layer at the perovskite/SnO 2 interfaces, as schematically illustrated in Figure S11. ,, Point defects such as interstitial sites (Sn i ) and oxygen vacancies (V O ) are known to be formed at the surface of SnO 2 film during fabrication. , These defects may serve as electron trap sites and promote the detrimental interfacial recombination with holes from the perovskites. The wide band gap PTI with a large VBM energy offset suppresses such hole quenching at the interface of perovskite/SnO 2 …”

“…46 interfaces, as schematically illustrated in Figure S11. 47,49,50 Point defects such as interstitial sites (Sn i ) and oxygen vacancies (V O ) are known to be formed at the surface of SnO 2 film during fabrication. 1,51 These defects may serve as electron trap sites and promote the detrimental interfacial recombination with holes from the perovskites.…”

Synergistic Effect of Anti‐Solvent and Component Engineering for Effective Passivation to Attain Highly Stable Perovskite Solar Cells

“…Adding functional additives to the precursor solution can dramatically reduce defects, improve the quality of perovskite films, and enhance the performance of PSC devices. According to the literature, [23][24][25][26][27][28] the PSCs prepared from precursor solutions containing some functional molecules that passivate the defects exhibited excellent performance. For example, Yang et al [29] used urea as an additive to improve the quality of perovskite films and reduce the density of defect states.…”