Sn‐Pb Mixed Perovskites with Fullerene‐Derivative Interlayers for Efficient Four‐Terminal All‐Perovskite Tandem Solar Cells. (1st December 2021)

• Record Type: Journal Article
• Authors: Hu, Hang; Moghadamzadeh, Somayeh; Azmi, Raheleh; Li, Yang; Kaiser, Milian; Fischer, Jan C.; Jin, Qihao; Maibach, Julia; Hossain, Ihteaz M.; Paetzold, Ulrich W.; Abdollahi Nejand, Bahram
• Is Part Of: Advanced functional materials. Volume 32:Number 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-01
• Subjects: all‐perovskite tandem solar cells -- charge extraction -- fullerene derivatives -- interlayers -- non‐radiative recombination -- Sn‐Pb mixed perovskites; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202107650
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Interfacial engineering is the key to high‐performance perovskite solar cells (PSCs). While a wide range of fullerene interlayers are investigated for Pb‐based counterparts with a bandgap of >1.5 eV, the role of fullerene interlayers is barely investigated in Sn‐Pb mixed narrow‐bandgap (NBG) PSCs. In this work, two novel solution‐processed fullerene derivatives are investigated, namely indene‐C60‐propionic acid butyl ester and indene‐C60‐propionic acid hexyl ester (IPH), as the interlayers in NBG PSCs. It is found that the devices with IPH‐interlayer show the highest performance with a remarkable short‐circuit current density of 30.7 mA cm −2 and a low deficit in open‐circuit voltage. The reduction in voltage deficit down to 0.43 V is attributed to reduced non‐radiative recombination that the authors attribute to two aspects: 1) a higher conduction band offset of ≈0.2 eV (>0 eV) that hampers charge‐carrier‐back‐transfer recombination; 2) a decrease in trap density at the perovskite/interlayer/C60 interfaces that results in reduced trap‐assisted recombination. In addition, incorporating the IPH interlayer enhances charge extraction within the devices that results in considerable enhancement in short‐circuit current density. Using a NBG device with an IPH interlayer, a respectable power conversion efficiency of 24.8% is demonstrated in a four‐terminal all‐perovskite tandem solar cell. Abstract : This study reports on novel solution‐processed fullerene derivatives, namely indene‐C60‐propionic acid butyl ester and indene‐C60‐propionic acid hexyl ester, as the interlayers in narrow‐bandgap perovskite solar cells as well as tandem solar cells. Their effects on the performance and non‐radiative recombination in the devices are systematically studied.