Passivation of Inverted Perovskite Solar Cells by Trifluoromethyl-Group-Modified Triphenylamine Dibenzofulvene Hole Transporting Interfacial Layers

Abstract

In this work, we synthesized trifluoromethyl group series modified triphenylamine dibenzofulvenes, named as CC-1–3, as a hole transporting interfacial layer to obtain well-matched energy levels and long-term stability features in NiOx-based inverted perovskite solar cells. The optical and thermal properties of these new compounds were investigated. All the compounds were combined with NiOx and formed layer by layer as hole transporting layers (HTLs). The morphology, energy level, and charge transfer resistance were all compared. The NiOx/CC-3 bilayer-based architecture improved the energy level alignment, film morphology, crystallinity, and hole transportation, allowing for a high-quality perovskite layer and interfacial contact behavior. As a result, this inverted cell significantly improved open-circuit voltage (V OC), short current density (J SC), fill factor (FF), and power conversion efficiency (PCE) values up to 21.66 mA cm–2, 1.105 V, 79.33%, and 19.82%, respectively. Remarkably, the NiOx/CC-3 device had negligible hysteresis and long-term stability, retaining over 90% of its original efficiencies under argon and over 80% in the ambient atmosphere after 40 days. This paper shows a new chemical design, particularly for the trifluoromethyl group effect, and a complete understanding of the bilayer HTL technique and its promise for producing efficient cell performance.

Assessing Performance and Limitations of a Device‐Level Machine Learning Approach for Perovskite Solar Cells with an Application to Hole Transport Materials

“…A 2021 paper by Cai et al [ 59 ] proposing new D– π –D phenoxazine‐based hole transport materials for high‐efficiency inverted solar cells was selected. The following papers suggesting different classes of materials as hole transport layers were also considered: modified triphenylamine dibenzofulvenes; [ 60 ] donor–acceptor–donor material with methoxy‐substituted TPA as the donor end group; [ 61 ] low‐symmetry monothiatruxene‐based HTL; [ 62 ] substituted pyrrole core with triphenylamine peripheral arms. [ 63 ] Suitable descriptors were extracted from the papers using the documentation of the main perovskite database [ 64 ] as a reference to consistently define categorical descriptors.…”

“…Comparison of predicted and experimental PCE. Panels a–d) refer to different papers as follows: a), [ 57 ] b), [ 58 ] c), [ 59 ] d), [ 60 ] e), [ 61 ] f), [ 62 ] g). [ 63 ] When available, a confidence interval has been represented as error bars, where σ is the reported experimental standard deviation.…”

Uniform Coverage Functional Layers Enable High‐Efficient Flexible Perovskite Solar Modules with an Outstanding Fill Factor

“…[21][22][23] The high nonradiative recombination gathered at the interface between the perovskite and NiO x limits the open-circuit voltage (V oc ) of NiO x -based PSCs. [24][25][26][27][28][29] These defects could be minimized by introducing a layer of self-assembled monolayer (SAM) between the perovskite and SP-NiO x . [30,31] Currently, SAMs of carbazole bodies with phosphonic acid binding groups, including [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz), are widely used in high-efficiency inverted PSCs and perovskite/silicon tandem cells.…”

Dibenzofulvene Derivatives as Promising Materials for Photovoltaic and Organic Electronics

“…First of all, this is due to the many advantages of compounds of this type, such as the possibility of modification through many chemical reactions, excellent thermal stability, the high quantum yield of photoluminescence, relatively good features of molecular self-assembly, ambipolar properties of charge transport (holes and electrons), many peculiar features regarding nonlinear optical properties, as well as very good photostability [40,50]. A very interesting variant of the mentioned compounds are dibenzofulvene derivatives (DBFs) (Figure 1) [32][33][34][35][37][38][39][40][41][42][43][44][45][46][48][49][50]. These compounds largely retain the properties of fluorene and its derivatives.…”

“…However, due to the carbon-carbon double bond (C=C) in the C9 position of fluorene and the additional substituent at the end of this bond, dibenzofulvene derivatives gain additional opportunities to modify their physicochemical properties. Thanks to this, dibenzofulvene derivatives are becoming increasingly popular compounds in various research [32][33][34][35][37][38][39][40][41][42][43][44][45][46][48][49][50].…”