A Binary Solution Strategy Enables High-Efficiency Quasi-2D Perovskite Solar Cells with Excellent Thermal Stability

Abstract

Quasi-two-dimensional (2D) perovskites are highly promising light-harvesting materials for commercialization of perovskite solar cells (PSCs) owing to the excellent materials stability. However, the coexistence of multiple n-value species in 2D perovskites often causes increased complexities in crystallization that can negatively affect the eventual photovoltaic performance. Herein, we present a binary solution based strategy via introducing nontoxic and widely accessible CH 3 COOH (HAc) as a co-solvent for preparing high-quality 2D perovskite films. Based on a 2D perovskite model system, (AA) 2 MA 4 Pb 5 I 16 (n = 5), we show that the prenucleation and grain growth kinetics are appreciably modified with HAc, which benefits from the strong electrondonating ability of HAc with the key component of PbI 2 , leading to formation of favorable cluster aggregates and resultant modulation of crystal growth. With the HAc-based method, the devices yield a boosted photovoltaic efficiency of 18.55% with an impressive photovoltage of 1.26 V. The champion cells exhibit a supreme thermal stability, showing <3% efficiency degradation under continuous thermal aging for 800 h.

Unveiling the Intrinsic Photophysics in Quasi-Two-Dimensional Perovskites

“…Such observations align well with prior studies. 27,28,30,38 Figure S5 shows the clear discrepancy in the rising dynamics between time-resolved PL and TA curves. This observation rules out the formation of bleach in the 3D phase due to energy transfer from the 2D phase and is instead attributed to the electron transfer from the 2D to the 3D phase.…”

“…Under back-excitation (Figure C), the bleach recovery at n = 3, 4, and 5 phases accompanies with the bleach formation of the 3D phase at the primary hundreds ps. Such observations align well with prior studies. ,,, Figure S5 shows the clear discrepancy in the rising dynamics between time-resolved PL and TA curves. This observation rules out the formation of bleach in the 3D phase due to energy transfer from the 2D phase and is instead attributed to the electron transfer from the 2D to the 3D phase.…”

Machine learning assisted designing of non-fullerene electron acceptors: A quest for lower exciton binding energy

“…RDKit is an open-source cheminformatics toolkit widely used for generating molecular descriptors. It is employed to comprehensively compute various molecular descriptors, encompassing structural, topological, and physicochemical properties of chemical compounds [ 33 ]. These molecular descriptors serve as input features in ML and are essential for developing prediction models.…”

Improved Photovoltaic Performance of Inverted Two-Dimensional Perovskite Solar Cells via a Simple Molecular Bridge on Buried Interface

“…Organic–inorganic halide perovskite solar cells (PSCs) have aroused broad research interest due to their remarkable photoelectric properties of high absorption coefficient, wide absorption range, tunable energy bandgap, as well as long charge carrier diffusion length. − Among them, the two-dimensional perovskite solar cells (2D-PSCs) are prepared by introducing organic spacer cations to partially replace methylamine ion (MA + ) or formamidine ion (FA + ) ions, which can greatly improve the wet stability and structure stability of the device. − Inverted 2D-PSCs achieved rapid development because of the matched energy level of the hole transport layer (HTL) and perovskite and their better perovskite morphology, thus obtaining higher photoelectric power conversion efficiency (PCE). , However, the inherent hygroscopic and acidic properties of PEDOT:PSS , and the poor solvent infiltration of PTAA, ,− which are the two most used HTL materials in inverted device, , impede the further development of photovoltaic performance and stability for inverted 2D-PSCs.…”