Ion Implantation-Modified Fluorine-Doped Tin Oxide by Zirconium with Continuously Tunable Work Function and Its Application in Perovskite Solar Cells

Abstract

In recent years, perovskite solar cells have drawn a widespread attention. As an electrode material, fluorine-doped tin oxide (FTO) is widely used in various kinds of solar cells. However, the relatively low work function (WF) (∼4.6 eV) limits its application. The potential barrier between the transparent conductive oxide electrode and the hole transport layer (HTL) in inverted perovskite solar cells results in a decrease in device performance. In this paper, we propose a method to adjust WF of FTO by implanting zirconium ions into the FTO surface. The WF of FTO can be precisely and continuously tuned between 4.59 and 5.55 eV through different dopant concentration of zirconium. In the meantime, the modified FTO, which had a WF of 5.1 eV to match well the highest occupied molecular orbital energy level of poly(3,4-ethylenedioxylenethiophene):polystyrene sulfonate, was used as the HTL in inverted planar perovskite solar cells. Compared with the pristine FTO electrode-based device, the open circuit voltage increased from 0.82 to 0.91 V, and the power conversion efficiency increased from 11.6 to 14.0%.

Giant Dielectric Constant and Superior Photovoltaic Property of the Mechanochemically Synthesized Stable CH3NH3PbBr3 in a Hole Transporter-Free Solar Cell

“…In the FTO/MAPbBr 3 /Ag device, which is like a conventional Schottky diode, band bending occurs and the electron can flow from MAPbBr 3 to the Ag electrode because of the p-type characteristic of MAPbBr 3 , (Figure b). It is to be noted that the work function difference between the Ag and FTO is 0.3 eV, which acts as in-built potential for the Schottky device. It is expected that built-in potential energy near the interface of Ag/MAPbBr 3 is greater than that at the MAPbBr 3 /FTO interface, as schematically shown in Figure b.…”

Device simulation of all-perovskite four-terminal tandem solar cells: towards 33% efficiency

“…In a tandem device, ITO is a choice of material for cathode, and it's workfunction depends on the film synthesis method, and pre/post treatment processes, i.e, cleaning (by organic solvents, ultrasonic bath, Ar sputtering and reactive ion etching, mixture of boiling deionized water, hydrogen peroxide, and ammonia) [71][72][73], and surface modification [74,76,77]. Fluorine-tin oxide (FTO) is another transparent conductive material for the contacts which exhibits a bandgap between À4.4 eV and À5.55 eV [71,78,79]. In many perovskite solar cells, FTO/ glass is used as substrate, where FTO serves as anode contact.…”

“…Workfunction tuning of transparent ITO can be achieved by controlling growth parameters, capacitively coupled plasma [109], and by using amino-functionalized polyfluorene and self-assembled monolayers [74,76,77]. Similarly, FTO workfunction can be tuned by controlling growth parameters, ion-implantation [78] and surface modification techniques [110,111]. Also, in the bottom cell, the bottom contact can be replaced by metal contact which is optically opaque.…”

Phase controlled synthesis of bifunctional TiO2 nanocrystallites viad-mannitol for dye-sensitized solar cells and heterogeneous catalysis

“…In DSSCs, on capturing photons over the N-719 dye layer, the electron-hole pairs are created, and the excited electrons are injected into the CBM of the A-TiO 2 NCs, which are then collected at the FTO substrate of the À4.6 eV work function more easily. 36…”