β-Alanine-Anchored SnO₂ Inducing Facet Orientation for High-Efficiency Perovskite Solar Cells

Abstract

SnO2 films as a promising electron transport layer (ETL) have been widely used in planar-type perovskite solar cells to achieve an impressive improvement in the conversion efficiency. However, compared with a mesoporous ETL, the interfacial charge carrier transfer of the SnO2 ETL is severely limited due to the issues of oxygen vacancy defects and crystal lattice mismatch between SnO2 and the perovskite, which generally leads to the growth of randomly stacked and porous perovskite layers and subsequently impacts the charge transport and transfer properties. In this work, we developed a facile approach by inducing a bifunctional molecule, β-alanine, into the SnO2 ETL, which can serve as a bridge to modulate the interfacial charge transfer and the perovskite crystallization kinetics. Benefited by the interfacial β-alanine, we grew a highly orientational perovskite layer that exhibited superior charge transport properties. Meanwhile, the β-alanine caused an intimate connection between the perovskite and SnO2 to enhance the interfacial charge transfer. As a result, the power conversion efficiency (PCE) of the β-alanine-modified device achieved a much-improved value of 19.67% and showed high reproducibility. This work provides a way for developing a high-performance ETL toward the scalable fabrication of highly efficient PSCs.

Alkali Metal Cations Modulate the Energy Level of SnO2 via Micro-agglomerating and Anchoring for Perovskite Solar Cells

“…In addition to the electrical conductivity of SnO 19,31 The enlarged region (Figure 5b) of the C�O stretching vibration is observed to shift toward large wavenumbers, illustrating that oxalate ions truly interact with SnO 2 . 44,45 Likewise, a new stretching peak appears at 770.7 cm −1 in SnO 2 -Na and SnO 2 -K, which is defined as Sn-O-Na and Sn-O-K, respectively. The peak intensity of −OH in the FTIR spectra of the SnO 2 film is weakened.…”

Chemi‐Mechanically Peeling the Unstable Surface States of α‐FAPbI3

“…We further measured the trap density of the FAPbI 3 perovskite films without and with PZ treatment by the space‐charge‐limited‐current (SCLC) method. [ 39 ] As shown in Figure 3h, we constructed an electron‐only device with an architecture of FTO glass/SnO 2 /perovskite/PCBM/Au, and the trap density was determined by fitting the current‐voltage response plots using Equation . $$\[ \begin{array}{*{20}{c}}{{{\rm{n}}_{{\rm{trap}}}} = \frac{{2{\varepsilon _0}\varepsilon {{\rm{V}}_{{\rm{TFL}}}}}}{{e{L^2}}}}\end{array} \]$$where ε 0 is the vacuum permittivity, ε is the relative dielectric constant of the FAPbI 3 , V TFL is the onset trap voltage of the trap‐filled limit region, e is the elementary charge, and L is the thickness of corresponding perovskite film.…”

Balancing Lattice Strain by Embedded Ionic Liquid for the Stabilization of Formamidinium-Based Perovskite Solar Cells

“…To further elucidate the charge carrier dynamics, time-resolved PL (TRPL) measurements were executed, and the results are displayed in Figure d. The charge carrier lifetime can be calculated by eq , that is, using a biexponential decay to fit the TRPL curve where τ 1 and τ 2 are related to interfacial charge carrier recombination and bulk recombination, respectively, representing fast and slow decay lifetime components; A 1 and A 2 refer to their decay magnitudes; and B is a given constant. , Equation is utilized to obtain the corresponding average carrier lifetime, denoted as τ ave . The τ 1 and τ 2 for the control perovskite film are 476.1 and 86.7 ns, respectively, resulting in an average lifetime of 252.3 ns, while for the IL-embedded perovskite film, the τ 1 and τ 2 improve to 782.0 and 140.9 ns, respectively, yielding an extended average lifetime, 431.4 ns, confirming the reduction of the trap density after the incorporation of IL.…”