Fully Solution‐Processed n–i–p‐Like Perovskite Solar Cells with Planar Junction: How the Charge Extracting Layer Determines the Open‐Circuit Voltage

Abstract

Fully solution-processed direct perovskite solar cells with a planar junction are realized by incorporating a cross-linked [6,6]-phenyl-C61-butyric styryl dendron ester layer as an electron extracting layer. Power conversion efficiencies close to 19% and an open-circuit voltage exceeding 1.1 V with negligible hysteresis are delivered. A perovskite film with superb optoelectronic qualities is grown, which reduces carrier recombination losses and hence increases V .

Interface passivation using ultrathin polymer–fullerene films for high-efficiency perovskite solar cells with negligible hysteresis

“…20% with Voc=1.17 V. The third approach to reduce interfacial recombination is to introduce a very thin passivation layer between the perovskite and transport layers. 18,19,[34][35][36][37][38][39] For example, Zhang et al 35 showed that a very thin fullerene derivative (α-bis-PCBM) layer between the perovskite and the Spiro-OMeTAD HTL can reduce cell degradation and passivate defects at the perovskite/HTL interface, yielding a PCE of 20.8%, and Voc= 1.13 V. Similarly, Koushik et al 37 and Wang et al 39 used ultrathin layers of Al2O3 and poly(methyl methacrylate) (PMMA) respectively to passivate the perovskite/Spiro-OMeTAD interface, resulting in improved Voc (1.08V and 1.06V respectively) and reduced hysteresis. Recently,…”

Additive Engineering to Grow Micron‐Sized Grains for Stable High Efficiency Perovskite Solar Cells

“…[18] By a two-step sequential ethyl acetate interfacial processing, Fei and co-workers employed thiourea as additive in the perovskite precursor to effectively control the nucleation and subsequent crystal growth processes presenting compact microsized and monolithically grained perovskite films. [21][22][23] Although the above mentioned additive can achieve large-grained perovskite films, unfortunately, fabricating perovskite films with much more larger grain sizes along with lower trap densities using a novel additive is still a new challenge. Recently, Cai et al [20] introduced trimethylammonium chloride (TACl) as additive to prepare perovskite films.…”

Elucidating the Origins of Subgap Tail States and Open‐Circuit Voltage in Methylammonium Lead Triiodide Perovskite Solar Cells

“…Most of the high‐efficiency, and therefore high V oc (>1 V), PSCs are fabricated with the conventional n–i–p structure, normally with planar or planar/mesoporous TiO 2 as an electron transport layer (ETL) deposited on a transparent electrode . The loss of V oc has been discussed in terms of interfacial recombination induced by top hole transport layers (HTLs), or by bottom ETL . Inverted devices, i.e., p–i–n architectures, comprising poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as bottom HTLs are associated with greater losses in photovoltage and their V oc is usually more than 100 mV lower than the V oc achieved with n–i–p devices .…”