Thermal Precursor Approach to Pristine Fullerene Film as Electron Selective Layer in Perovskite Solar Cells

Abstract

In perovskite solar cells (PSCs), electron selective layers (ESLs) assume a crucial role in blocking holes and transporting electrons for high performances. To achieve low-temperature solution processing of PSCs, organic n-type materials such as fullerene-based molecules have recently been employed to replace a typical TiO 2 ESL that requires high temperature (>450 • C) for fabrication. Herein, soluble C 60 -9-methylanthracene mono-adduct (C 60 (9MA)) is used as a thermal precursor to the C 60 ESL in planar PSCs.The best performing PSC device shows a power conversion efficiency of 15.0% under the simulated AM 1.5G one sun illumination, which is superior to that of the device with compact TiO 2 as an ESL (12.9%). Remarkably, a fill factor of the C 60 -based PSC (0.723) is enhanced compared to that of the TiO 2 -based one (0.671) owing to the low charge-transfer resistance at the interface of C 60 -perovskite. These results suggest that the thermal precursor approach to pristine fullerene films is a promising approach for fabricating ESL in high-performance PSCs with relatively low fabrication temperature (<140 • C).

The role of carbon-based materials in enhancing the stability of perovskite solar cells

“…36,37 Different fullerene derivatives such as cis-a-dimethoxy carbonyl fulleropyrrolidine C 70 (DMEC 70 ), cross-linked silanemodified fullerene, and doped fullerene have been used as ESLs in p-i-n planar heterojunction structure 28,52,53 and later in the n-i-p architecture. 54 Umeyama et al 55 reported for the first time the use of C 60 thin films as the ESL in regular n-i-p PSCs, after thermal retro-Diels-Alder reaction on as-prepared glass/FTO/C 60 -9-methylanthracene. Fullerene ESLs have also been doped with various materials such as decamethylcobaltocene, 56 oleamide, 29 carbon, and novel two-dimensional carbon materials such as graphdiyne 57 for application in PSCs.…”

The Influence of Helium Dielectric Barrier Discharge Jet (DBDjet) Plasma Treatment on Bathocuproine (BCP) in p-i-n-Structure Perovskite Solar Cells

“…Compared to the PSCs without the He DBDjet treatment, the PSCs with the He DBDjet treatment exhibited smaller hysteresis, defined as (PCE (forward scan)-PCE (reverse scan))/PCE (forward scan), as shown in Figure S1 [4,52,53]. Many parameters influence the J-V hysteresis behavior of the PSCs, such as the voltage range, scan direction, scan rate, architecture, and precondition of PSCs [54][55][56][57][58][59][60][61][62][63]. In this case, without the He DBDjet treatment on the BCP layer, the unbalanced electron and hole transport rates as well as interface defects may cause photocurrent hysteresis [4,52,53].…”