Surface Re-Engineering of Perovskites with Buckybowls to Boost the Inverted-Type Photovoltaics

Abstract

Despite their multifaceted advantages, inverted perovskite solar cells (PSCs) still suffer from lower power conversion efficiencies (PCEs) than their regular counterparts, which is largely due to recombination energy losses (E loss) that arise from the chemical, physical, and energy level mismatches, especially at the interfaces between perovskites and fullerene electron transport layers (ETLs). To address this problem, we herein introduce an aminium iodide derivative of a buckybowl (aminocorannulene) that is molecularly layered at the perovskite–ETL interface. Strikingly, besides passivating the PbI2-rich perovskite surface, the aminocorannulene enforces a vertical dipole and enhances the surface n-type character that is more compatible with the ETL, thus boosting the electron extraction and transport dynamics and suppressing interfacial E loss. As a result, the champion PSC achieves an excellent PCE of over 22%, which is superior compared to that of the control device (∼20%). Furthermore, the device stability is significantly enhanced, owing to a lock-and-key-like grip on the mobile iodides by the buckybowls and the resultant increase of the interfacial ion-migration barrier. This work highlights the potential of buckybowls for the multifunctional surface engineering of perovskite toward high-performance and stable PSCs.

Grain Boundary and Buried Interface Suturing Enabled by Fullerene Derivatives for High-Performance Perovskite Solar Module

“…The Pb signal shift probably indicates that unsaturated Pb 2+ accepts a lone pair of electrons from the fluorine atom within FPAC 60 . 21,22 This consequence is also supported by the calculation of the electrostatic potential (ESP) of FPAC 60 (Figure S9). The shift of the I signal can be attributed to the electron-deficient C 60 cage, which could interact with iodide ions to suppress their migration and reduce the formation of deep traps.…”

Crystal growth of two-dimensional organic–inorganic hybrid perovskites and their application in photovoltaics

“…The conjugated organic tail can enhance the orderly accumulation of the barrier layer, which may increase the carrier mobility with low dielectric constant. 74 Another possible solution for improving the photovoltaic performance of the R–P perovskite is introducing heteroatoms in the chain or aromatic ring, especially fluorine-substituted organic cations (such as 4FPEA + , 84 F5PEA + (ref. 69)).…”

“…4 Chemical structure of the commonly used A-site organic cations for fabricating R-P (blue color), D-J (red color), and ACI (pink color) perovskite films. GuA, 27,49 EA, 50 PA, 45 BA, 18,21,26,[51][52][53][54][55][56] HA, 14 OA, 57,58 OAm, 57 TMA, 59 ThFA, 60 ThEA, 7,61,62 BThEA, 63 VBA, 64,65 PEA, 66 4FPEA, 47,67,68 4MPEA, 48 F5-PEA, 69,70 NMA, 71 AnMA, 72 PREA, 73 CorMA, 74 EDA, 23,24 PDA, 75,76 , 81 m-DMPA, 37 ThDMA, 46 TTDMA, 82 and C 60 -BPAM. 83 heteroatom substitution (Fig.…”

Surface termination passivation of imidazole-based diiodide enabling efficient inverted perovskite solar cells

“…Amino-corannulene iodides were introduced on the surface of the perovskite by Yang et al , leading to a significant reduction of the Pb 2+ traps owing to the favorable coordination ability between R-NH 3 + and Pb 2+ . 11 Simultaneously, ammonium diiodide salts, such as ethane-1,2-diamine diiodide, histamine diiodide, have also been adopted as modifiers to mitigate the defect density of perovskite at the top and bottom interface of PSCs. 12,13 However, the above ammonium salts have only one functional group binding to the Pb 2+ traps for passivation.…”

“…3b) image of PSC shows a clear compositional structure with a suitable thickness (∼680 nm) of the perovskite layer. 11 For the regulation of perovskite surface properties, the concentration of functional compounds is extremely critical. Here, the optimal concentration of APDI (0.3 mg/ml) was determined by the current density–voltage ( J – V ) test, as shown in Fig.…”