Electronic structure and interfacial features of triphenylamine- and phenothiazine-based hole transport materials for methylammonium lead iodide perovskite solar cells

Abstract

Recently, great research efforts have been devoted to perovskite solar cells (PSCs) leading to sunlight-to-power conversion efficiencies above 25%. However, several barriers still hinder the full deployment of these devices....

Stable Methylammonium‐Free p‐i‐n Perovskite Solar Cells and Mini‐Modules with Phenothiazine Dimers as Hole‐Transporting Materials

“…Based on the above considerations and on the results of our previous computational investigations, [38,39] we synthesized two new small molecule HTMs, named BPT-1,2, still featuring a TPA-PTZ backbone but characterized by a dimeric structure (Figure 1), which had not been investigated before and was expected to impart favorable electronic properties to the compounds (see below). Small-scale MA-free PSCs built with BPT-1 and BPT-2 showed average power conversion efficiencies (PCE) of 16.89% (17.26% max.)…”

Less Is More: Simplified Fluorene-Based Dopant-Free Hole Transport Materials Promote the Long-Term Ambient Stability of Perovskite Solar Cells

“…We analyzed the interactions of our SCF-HTMs with the perovskite surface and compared them to those involving the Spiro-OMeTAD reference. While the interfacial behavior of Spiro-OMeTAD has been studied on different MAPI surfaces by a theoretical point of view, − no computational studies have explored the interface with the triple-cation perovskite so far. Here, we addressed all possible surface terminations of the triple-cation perovskite active layer for modeling the HTM/perovskite interactions.…”

First-principles study of interfacial features and charge dynamics between spiro-MeOTAD and photoactive lead halide perovskites

“…Most of the charge rearrangement at the interface involves the fluorene ring and the methoxy groups of spiro-MeOTAD, which interact predominantly with the A cation and with the Pb atoms of AX and PbX 2 terminations, in agreement with previous investigations. 12,13 This analysis points out also a direct role of the Cs atom in stabilizing the interaction with spiro-MeOTAD. In the CsFAMAX(O–Cs) system, the increased charge density along the methoxy O–Cs bond and the O–Cs distance (∼3.25 Å) suggests the formation of direct bonding.…”

“…For these reasons, we also considered different local compositions of both terminations in triLHP (Fig. S2, ESI †): AX terminations exposing or not the Cs atom (CsFAMAX and FAMAX in the text, respectively), plus an additional CsFAMAX layer with a maximized interaction of Cs with the most active methoxy groups of spiro-MeOTAD, 12,13 CsFAMAX(O-Cs). Similarly, we considered two PbX 2 -terminated surfaces, lacking or containing a Cs atom at the subsurface layer, PbX 2 and PbX 2 (Cs), respectively.…”