Fast Charge Transfer and High Stability via Hybridization of Hygroscopic Cu-BTC Metal–Organic Framework Nanocrystals with a Light-Absorbing Layer for Perovskite Solar Cells

Abstract

Perovskite solar cells (PSCs) have great potential as an efficient solar energy harvesting system due to their outstanding optoelectronic properties, but the charge accumulation and recombination, as well as the moisture-induced degradation of the light-absorbing perovskite layers, remain great bottlenecks in practical applications for future technology. As a solution to this challenge, here we report a strategy to realize moisture-stable PSCs allowing fast charge transfer that, in turn, leads to high power conversion efficiency (PCE). Hybridization of hygroscopic copper­(II) benzene-1,3,5-tricarboxylate metal–organic frameworks (Cu-BTC MOFs) with a light-absorbing perovskite layer for PSCs, where a moderate level of moisture attracted by Cu-BTC MOFs during the synthesis step, leads to enhanced perovskite crystallization. Besides, the perovskite–MOF hybrid facilitates the transfer of photoexcited electrons from the perovskite to TiO2 by providing additional channels for electron extraction. This enables a high PCE of 20.5% in a triple-cation perovskite–MOF device with negligible hysteresis compared to reference devices. Moreover, the perovskite–MOF hybrid exhibits high stability in ambient air under dark conditions over a long period (up to 22 months), while the unmodified counterpart quickly decomposes into PbI2. Consequently, this work provides a promising clue to realizeing fast charge transfer and high stability for high-performance PSCs.

Confinement of MACl guest in 2D ZIF-8 triggers interface and bulk passivation for efficient and UV-stable perovskite solar cells

“…It was further confirmed that the modification of the buried interface by MACl@ZIF-8 accelerated the electron transfer. 4,56 To evaluate the trap density of the perovskite films on different ETLs, we performed space-charge limited current (SCLC) measurements by employing the electron-only structure of FTO/SnO 2 /perovskite/PCBM/Ag. Fig.…”

Interface Modification by FAI@ZIF‐8 for High‐Efficiency Perovskite Solar Cells

“…This result comes from a more efficient extration of photo‐generated carrier from the perovskite to the TiO 2 . [ 59 ] The TRPL spectra are fitted by the doubled‐exponential decay function f ( t ) = A 1 exp(− t / τ 1 ) + A 2 exp(− t / τ 2 ), where A 1 and A 2 are the decay amplitudes, and τ 1 and τ 2 are the decay time constants. [ 60 ] The fitted parameters are summarized in Table S2, Supporting Information.…”

Crystalline porous materials in perovskite solar cells: a mutually beneficial marriage

“…Small-sized CPMs. Small-size MOFs, typically with diameters less than 5 nm, can be obtained by adjusting the concentration of reactants 39 or by using ultrasound-assisted methods, [40][41][42] which is also the strategy adopted by most poorly soluble MOFs. Such small sizes being incorporated into the perovskite layer do not lead to an inhomogeneous multilayer structure.…”