Synergetic Regulation of Oriented Crystallization and Interfacial Passivation Enables 19.1% Efficient Wide‐Bandgap Perovskite Solar Cells

Abstract

show promising applications in buildingintegrated photovoltaics and Internet of Things. [4] Despite their numerous studies, WBG PSCs still suffer from severe opencircuit voltage loss (V loss ) and instability. Extensive investigations indicate that the rigorous V loss is attributed to high-density defects and photoinduced phase segregation. [5] The polycrystalline perovskite films prepared by solution methods have numerous defects at grain boundaries, surface, and perovskite bulk, [6] which act as trapping sites that cause strong nonradiative recombination. The nonradiative recombination decreases the steady-state charge density and reduces the splitting of quasi-Fermi levels, finally leading to a relatively large V loss . [7] Besides, surface defects at grain boundary provide channels for moisture invasion as well as ion migration, resulting in detrimental stability. [8] Various strategies including additive engineering, [9] composition engineering, [10] solvent engineering, [11] and interface engineering, [5b] are effectively employed to fabricate high-efficiency WBG PSCs. Among them, using additives in perovskite precursors is a common method to fabricate highquality WBG PSCs. The functions of additives are mainly to improve the film quality, [12] passivate defects, [13] and inhibit phase segregation. [14] For example, Yan and co-workers reported that lead thiocyanate additive can availably increase the grain size to 1 µm and enhance the crystallinity of WBG perovskite films. [11] Recently, 2D/3D heterostructure formed by interfacial passivation attracts great attention for WBG PSCs with high power conversion efficiency (PCE) and superior stability. [5a,15] A 2D/3D heterostructure, formed by depositing large organic cation onto 3D WBG perovskite, can efficaciously passivate the surface defect, [16] block ion migration, [17] and enhance the stability of WBG PSCs. [18] Furthermore, the optimized energylevel arrangement of the 2D/3D heterostructure can decrease the V loss . [5a,19] To date, most of the reported studies focus on one single strategy to modify either perovskite crystallization or interface passivation, or others. Therefore, it is of great interest to develop synergetic strategies to regulate the crystallization and defect passivation for achieving highly efficient WBG PSCs.In this study, we introduce a dual-functional agent of 4-fluorophenylethylammonium iodide (FPEAI) to achieve synergetic modulation of perovskite crystallization and comprehensive Wide-bandgap (WBG) perovskite solar cells (PSCs) suffer from severe voltage loss, which significantly limits the enhancement of photovoltaic performance. Here, 4-fluoro-phenylethylammonium iodide (FPEAI) is used as a dualfunctional agent for oriented crystallization and comprehensive passivation of WBG PSCs. The additive of FPEAI promotes crystals to grow along with the (100) orientation with improved crystallinity and to spontaneously form Ruddlesden-Popper 2D perovskite on the grain boundary and surface of 3D crystals, which can passivate defect...

Over 24% Efficient Poly(vinylidene fluoride) (PVDF)‐Coordinated Perovskite Solar Cells with a Photovoltage up to 1.22 V

“…[24,37] Other research proposed the concept that the polymer as the template can modulate the nucleation and growth of perovskite film, but how the polymer modulate the crystallinity process of perovskite remains unclear. [33,36,39] Furthermore, among various additives, fluorinate additives incorporated into perovskite layer [42][43][44] or as the interlayer on top of perovskite [45,46] facilitate the formation of hydrogen-fluorine bonds with organic cations, which protects perovskite from moisture.…”

Rational Design of Ferroelectric 2D Perovskite for Improving the Efficiency of Flexible Perovskite Solar Cells Over 23 %

“…Similar results have also been reported in 2D/3D hybrid systems previously. [39] Recent studies have demonstrated that the strains in perovskite film played a vital role in governing the carrier dynamics. [42] Here, the effects of 2D perovskite addition on regulating the film strains were investigated by depthresolved grazing incident X-ray diffraction (GIXRD) technique with 2θ-sin 2 ψ method.…”

Antimony Potassium Tartrate Stabilizes Wide-Bandgap Perovskites for Inverted 4-T All-Perovskite Tandem Solar Cells with Efficiencies over 26%

“…For example, Yu et al . reported that 4-fluoro-phenylethylammonium iodide as a bifunction additive promoted perovskite crystals to grow along with the (100) orientation and comprehensively passivated WBG perovskites, achieving a V OC of 1.30 V in WBG PSCs [ 33 ]. Potassium halides have been introduced to WBG perovskites to passivate defects, suppress ion migrations [ 32 , 34 , 35 ].…”