Improving Performance and Stability of Planar Perovskite Solar Cells through Grain Boundary Passivation with Block Copolymers

Abstract

Organic–inorganic metal halide perovskite solar cells (PSCs) exhibit excellent photovoltaic performance but have the drawbacks of instabilities against moisture and heat due to the inherent hydroscopic nature and volatility of their organic components. Herein, it is reported that using the block copolymer F127 as the passivation reagent in conjunction with the solvent annealing process can efficiently improve the performance and stability of corresponding organic–inorganic PSCs. It is anticipated that the hydrophilic poly(ethylene oxide) tails of F127 polymers connect with contiguous perovskite crystals and passivate defects at perovskite grain boundaries, whereas the dangling hydrophobic poly(phenyl oxide) centers suppress perovskite decomposition caused by moisture and heat. After the optimization of the F127 additive, planar PSCs with champion power conversion efficiencies of 21.01% and 18.71% are achieved on rigid and flexible substrates, respectively. The F127 passivation strategy provides an effective approach for fabricating high‐efficiency and stable PSCs.

Stretchable Perovskite Solar Cells with Recoverable Performance

“…[14][15][16][17][18][19] Challengingly,perovskite films on flexible substrate are naturally brittle and possess poor crystallinity and numerous grain boundaries. [20][21][22] Theg rain boundary of perovskite has been verified as ac rucial defect that contributes to the efficiencya nd environmental stability loss of PSCs. [23][24][25][26] In fact, carrier recombination and ionic migration of perovskite films primarily occur at the grain boundaries.A tmospheric water and oxygen easily corrode the perovskite crystals through grain boundaries.…”

“…[27][28][29][30] Moreover,w hen am echanical displacement is applied to perovskite films,c racks are first observed at the grain boundaries.T his kind of mechanical fracture is difficult to correct through self-healing,t hus resulting in poor mechanical stability. [22,31,32] To overcome these issues,great efforts in additive and interface engineering have been reported to improve the crystallization quality of flexible perovskite films.F or example,s ome organic molecules or polymer scaffolds are successfully doped into perovskite to enhance and repair the crystal. [20,33] Furthermore,some metal oxide interfacial materials have been used to improve the PCE of flexible PSCs with as atisfactory bendability.…”

High‐Performance Flexible Perovskite Solar Cells via Precise Control of Electron Transport Layer

“…[1][2][3][4] The power conversion efficiency (PCE) reduced the trap density of perovskite films. [30] Meanwhile, it has been proposed that the charge selective layer sandwiched between the top electrode and perovskite layer is used to improve the performance of f-PSCs. [30] Meanwhile, it has been proposed that the charge selective layer sandwiched between the top electrode and perovskite layer is used to improve the performance of f-PSCs.…”

Surface Passivation of Perovskite Solar Cells Toward Improved Efficiency and Stability

“…Recently, many groups have succeeded in utilizing the interface engineering strategy to minimize the influence of moisture and improve the stability. Likewise, many interfacial materials have been investigated (Table S1), including metal oxides [19], polymers [20][21][22][23], and carbon-based materials [24]. These hydrophobic interfaces can not only substantially limit the permeation of atmospheric moisture but also enhance the device performance in terms of decreasing surface recombination, tuning band energy offsets, and optimizing interfacial contact [25].…”