Reducing Photovoltage Loss in Inverted Perovskite Solar Cells by Quantum Dots Alloying Modification at Cathode Contact. Issue 3 (22nd November 2019)

• Record Type: Journal Article
• Authors: Wang, He; Song, Yilong; Dang, Song; Jiang, Nairong; Feng, Jing; Tian, Wenjing; Dong, Qingfeng
• Is Part Of: Solar RRL. Volume 4:Issue 3(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-11-22
• Subjects: electron transport layers -- inverted planar heterojunction perovskite solar cells -- passivation -- perovskite quantum dots -- photovoltages; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201900468
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : The tremendous passion for inverted planar heterojunction perovskite solar cells (PSCs) is originated from their great tendency in the roll‐to‐roll process‐compatible fabrication and huge potential for integration into tandem solar cells. But the device efficiency is still lower than regular structured PSCs. Engineering of the cathode interface to efficiently control and reduce V OC loss lights a lamp for increasing electrochemical properties and boosting overall performance. Herein, a simple interfacial modification strategy is developed by introducing a hybrid ligand interfacial layer to reduce V OC loss in PSCs with inverted planar structure. Heavily washed QDs are used as neutral charged intermedia to enable alloying reaction to transfer ligands without damage to perovskite (PVK). A band bending is immediately generated on the top surface of PVK film after QDs modification, which is directly confirmed by ultraviolet photoelectron spectroscopy (UPS) and Kelvin probe force microscopy (KPFM). This contributes to ≈50 mV reduced V OC loss, leading to a V OC of 1.15 V and a power conversion efficiency (PCE) of 20.6% in inverted PSCs. Meanwhile, enhanced stability is achieved for these devices after QDs modification, in which PCE is maintained at >90% of initial value after 1000 h storage. Abstract : Quantum dots are regarded as neutralized charged intermedia to transfer ligands for interfacial modification, which can significantly adjust surface electric properties to reduce V OC loss and improve device performance. A stable V OC enhancement with excellent reproducibility is fulfilled by simple solution‐processed QDs modification, achieving 20.6% power conversion efficiency (PCE) and enhanced stability.