New thiophene-based C₆₀ fullerene derivatives as efficient electron transporting materials for perovskite solar cells

Abstract

The synthesis of new C60 fullerene derivatives functionalized with thiophene moieties as well as with electron donating or electron withdrawing groups, bromine (Br) or cyano (CN), respectively, using Bingel reactions is reported. The synthesized derivatives were used as the electron transporting materials (ETMs) in inverted perovskite solar cells (PSCs). Compared to devices fabricated with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), the new derivatives showed similar electrochemical properties and electron mobilities. However, PSCs based on the new derivatives synthesized in this work exhibited higher power conversion efficiencies (PCEs) than PC61BM based devices, which were ascribed to their better passivation ability, likely due to specific interactions between the fullerene addend and the perovskite layer surface. Devices based on the fullerene bearing the CN group exhibited an additionally improved efficiency due to the increased dielectric constant (εr) of this derivative. These results show that the new functionalized fullerene derivatives can act as efficient ETMs in inverted PSCs.

Enhanced Open-Circuit Voltage in Perovskite Solar Cells with Open-Cage [60]Fullerene Derivatives as Electron-Transporting Materials

“…A PSC consists of a sandwiched structure containing a transparent conductive oxide, a hole transport layer (HTL), a perovskite photo-absorber layer, an electron-transport layer (ETL), and a back-contact electrode [9,10,11,12,13,14,15]. Among the various cell configurations available for PSCs, the inverted planar structure (p-i-n) (Figure 1) is the most attractive in terms of manufacturing, because the ETL, which is typically a fullerene derivative, is solution-processed [16], as opposed to the metal oxides employed in the regular planar and mesoscopic configurations, which require high-temperature annealing steps [17,18,19].…”

Synthesis and characterization of C60 and C70 acetylacetone monoadducts and study of their photochemical properties for potential application in solar cells

“…Previous studies reported that Bingel derivatives of C 60 and C 70 exhibit quasi and reversible cathodic electrochemical behavior [39][40][41] CV of C 60diacetylmethane (3) and C 70 -diacetylmethane (5) compounds were recorded at a scan rate of 100 mV/s (Table 1 and Figure 8). Compound (3) exhibits seven irreversible reduction peaks in which four are well-defined.…”

Organic and Organic-Inorganic Solar Cells: From Bulk Heterojunction to Perovskite Solar Cells

“…Recently, we systematically studied the effect of new C 60 fullerene derivatives functionalized with thiophene moieties as well as with electron donating or electron withdrawing groups bromine (Br) or cyano (CN) (1-4, respectively, figure 8), when used as the ETLs in O-IPSCs [77]. The photo conversion efficiencies of O-IPSCs based on these compounds were higher than those of devices based on PC 61 BM, which was Volume 1 • Issue 1 • 1000101 Int J Chem Res.…”

“…The photo conversion efficiencies of O-IPSCs based on these compounds were higher than those of devices based on PC 61 BM, which was Volume 1 • Issue 1 • 1000101 Int J Chem Res. ISSN: 2642-1615 associated with the better passivation ability, due to specific interactions between S•••Pb atoms [77]. Important facts when synthesizing new ETLs are solubility and electron mobility, which need to be balanced.…”