Chromium‐Based Metal–Organic Framework as A‐Site Cation in CsPbI₂Br Perovskite Solar Cells

Abstract

Inorganic CsPbI x Br 3−x perovskite solar cells (PSCs) have gained enormous interest due to their excellent thermal stabilities. However, their intrinsically poor moisture stability hampers their further development. Herein, a chromium-based metal-organic framework group is intercalated inside the inorganic PbI framework, resulting in a new multiple-dimensional electronically coupled CsPbI 2 Br perovskite. In this structurally and electronically coupled perovskite, the π-conjugated terpyridyl can delocalize the excited valence electrons of metal Cr 3+ ion, enabling multi-interactive charge-carrier transport channels within CsPbI 2 Br perovskites. The stability and efficiency of the produced devices are substantially enhanced in comparison to their counterparts with only a pristine CsPbI 2 Br active layer. The optimized all-inorganic PSC yields a power conversion efficiency (PCE) as high as 17.02%. Remarkably, the stabilized device retains 80% of its PCE after 1000 h in the ambient atmosphere. This study provides a new paradigm toward addressing the stability challenge of the inorganic perovskite while enhancing its carrier transport ability.

2D/3D heterostructured CsPbI2Br solar cells: a choice for a monolithic all-perovskite tandem device

“…26 In situ growth of quasi-2D perovskites to form 2D/3D heterostructured PSCs has been proven to be effective in addressing these issues because quasi-2D perovskites provide a defect-free interface and modied energy band which allow minimizing charge recombination at the interface and act as a protective layer for 3D perovskites. [27][28][29][30][31][32][33][34][35][36][37] For example, Tai et al spin-coated BAI on top of a CsPbI 2 Br perovskite layer to form a 2D/3D heterostructure through the cation exchange reaction between BA + and Cs + , yielding a PCE of 14.5% and enhanced humidity stability. 38 Li et al used benzimidazolium iodide to post-treat a 3D CsPbI 2 Br lm, which resulted in an inverted 2D/ 3D PSC with a PCE of 14.32% as well as excellent environmental stability.…”

A Universal Grain “Cage” to Suppress Halide Segregation of Mixed-Halide Inorganic Perovskite Solar Cells

“…In agreement with DFT calculations, the localized charge traps caused by under-coordinated Pb 2+ are effectively delocalized over the whole lattice based on the charge density profiles and electron localized function (ELF) patterns (Figure a,b). By further analyzing the plot of density of states (DOS) of CsPbIBr 2 films (Figure c), we observe a new hybridized state overlapped between the wave function of iodine vacancy and the surface slab to eliminate the trap state, that is, the reduction of charge recombination centers. , It should be noted that the peak at 1.66 eV belongs to the orbitals of C 2p and N 2p of COF at the perovskite surface. − To quantitatively evaluate the defect density of perovskite films, we recorded the dark current density–voltage ( J – V ) curves of electron-only devices with the structure of FTO/c-TiO 2 /CsPbIBr 2 or COF-CsPbIBr 2 /PCBM/carbon using the space charge-limited current (SCLC) method . As shown in Figure d, the reduced trap filling limit voltage ( V TFL ) from 1.23 to 1.15 V enables the defect density of 1.98 × 10 16 cm 3 for the optimized device, which is much lower than that of the control device (2.11 × 10 16 cm 3 ).…”

Overcoming Perovskite Corrosion and De-Doping Through Chemical Binding of Halogen Bonds Toward Efficient and Stable Perovskite Solar Cells

“…Halogen bonds can protect perovskites from corrosion decomposition, so as to reduce the formation of defects. Then, the hole-only device with ITO/PEDOT: PSS/FA 1-x MA x PbI 3 /spiro/Ag geometry was constructed and the space charge limited current (SCLC) method was used to calculate the trap density ( N t ) of perovskite films [ 47 ]. With the complex formed through halogen bonds, the N t of the perovskite film decreased from 2.56 × 10 15 to 1.60 × 10 15 cm −3 (Fig.…”