Improved Performance and Stability of Inverted Planar Perovskite Solar Cells Using Fulleropyrrolidine Layers

Abstract

Inverted planar structure perovskite solar cells (PSCs), due to their low-temperature precessing and lack of hysteretic problems, are attracting increased attention by researchers around the world. Fullerene derivatives are the most widely used electron transport materials (ETMs) in inverted planar perovskite solar cells, especially [6,6]-phenyl-C-butyric acid methylester (PCBM), which exhibits very good performance. However, to the best of our knowledge, the influence of adducts on fullerene-based PSCs performance has not been fully explored to date. In this work, two fullerene derivatives, 2,5-(dimethyl ester) C fulleropyrrolidine (DMEC) and the analogous C derivative (DMEC), were synthesized in high yield via a 1,3-dipolar cycloaddition reaction at room temperature and incorporated into CHNHPbI perovskite solar cells as electron transport materials. Possibly because the attached pyrrolidine ester groups are able to coordinate with the perovskite layer, the devices based on DMEC and DMEC achieved power conversion efficiencies (PCE) of 15.2% and 16.4%, respectively. Not only were both devices' efficiencies higher than those based on PCBM and PCBM, but their stabilities were also higher than those for PCBM-based devices. The results suggest that DMEC and DMEC are better alternatives than PCBM and PCBM for the ETMs in PSCs.

Impact of fullerene derivative isomeric purity on the performance of inverted planar perovskite solar cells

“…These results were attributed to the ability of the mix-DMEC 70 to extract electrons efficiently, likely due to specific interactions between the pyrrolidine groups (carbonyls and amino groups) and the perovskite crystals at the interfaces. 27 There are three regioisomers in mix-DMEC 70 ( cis -α, cis -β- endo and cis -β- exo ) as shown in Fig. 1a.…”

Cove‐Edge Nanoribbon Materials for Efficient Inverted Halide Perovskite Solar Cells

“…These layers are invaluable because they determine the polarity of the device,i mprove stability,p assivate surface charge traps,a nd aid in chargeextraction transport from the active layer to the electrodes ( Figure 1). [11] However,the ETM is limited mainly to fullerenes such as PC 61 BM and other derivatives, [12][13][14][15][16][17] and there are few examples of efficient non-fullerene inverted PSCs reported. Despite the lower PCE at present, the inverted planar devices, which are based on p-i-n configurations,a re attractive because the relatively simple device architecture is promising for flexible devices and is amenable to low-temperature and scalable fabrication techniques.…”

“…[9,10] There are many hole transporting materials (HTMs) suitable for this type of solar cells.F or example,p oly(3,4-ethylenedioxythiophene):poly-(styrenesulfonate) (PEDOT:PSS), NiO x ,CuI, and CuSCN are all commonly used. [11] However,the ETM is limited mainly to fullerenes such as PC 61 BM and other derivatives, [12][13][14][15][16][17] and there are few examples of efficient non-fullerene inverted PSCs reported. [18][19][20][21] To further enhance PSCs,n ew ETMs must be developed and studied.…”

The 3 D Structure of Twisted Benzo[ghi]perylene‐Triimide Dimer as a Non‐Fullerene Acceptor for Inverted Perovskite Solar Cells

“…This indicates that the π‐conjugated plane of the small BPTI molecule not only is a function of electron transport but also plays an effective passivation role to reduce the surface and grain boundary trap states of the perovskite. Moreover, the less steric hindrance of carbonyl moieties on the five‐membered imide ring with the n ‐butyl group on BPTI have a good chance for interfacial complexation with lead atoms as defective states on the perovskite surface and then probably contribute to the effective Lewis base passivation . To further investigate the electron‐trap density states at the perovskite/ETL interface, we fabricated electron‐only devices with the device architecture: ITO/PCBM/MAPbI 3 /BPTI or t‐BPTI/BCP/Al.…”

“…Moreover,t he less steric hindrance of carbonyl moieties on the five-membered imide ring with the n-butylg roup on BPTI have ag ood chance for interfacial complexation with lead atoms as defective states on the perovskite surface and then probably contribute to the effective Lewis base passivation. [54][55][56] To further investigate the electron-trap density states at the perovskite/ETL interface, we fabricated electron-only devices with the device architecture:I TO/PCBM/ MAPbI 3 /BPTI or t-BPTI/BCP/Al. Figure 5s hows the I-V curveso ft hese devicesu nder dark conditions.…”