CuSCN as Hole Transport Material with 3D/2D Perovskite Solar Cells

Abstract

We report stable perovskite solar cells having 3D/2D perovskite absorber layers and CuSCN as an inorganic hole transporting material (HTM). (Phenylethyl)­ammonium (PEA) and [(4-fluorophenyl)­ethyl]­ammonium (FPEA) have been chosen as 2D cations, creating thin layers of (PEA)2PbI4 or (FPEA)2PbI4 on top of the 3D perovskite. The 2D perovskite as an interfacial layer, neutralizes defects at the surface of the 3D perovskite absorber, and can protect from moisture-induced degradations. We demonstrate excellent charge extraction through the modified interfaces into the inorganic CuSCN HTM, with device efficiencies above 18%, compared to 19.3% with conventional spiro-OMeTAD. Furthermore, we show significantly enhanced ambient stability.

Titanium‐Based Vacancy‐Ordered Double Halide Family in Perovskite Solar Cells

“…It has a wide bandgap, improved long-term ambient moisture stability, high optical transparency, and high mobility properties, potentially further enhancing PCE. [62,63] It also can be deposited at low temperatures using a range of solution-processing methods. [64] This circumvents the detrimental effect on perovskite films during device fabrication, thus increasing device stability.…”

Triaxial Perovskite Composite Fibers Spinning the Way to Flexible Solar Cells

“…[18,19] As a heating step (up to 135 C) is inevitable in here presented electrospun fibers, spiro-OMeTAD (which is subject to severe morphological deformation upon thermal treatment) [18] was replaced by inorganic CuSCN that has already been used in planar perovskite solar cells and had successfully replaced commonly used spiro-OMeTAD to deliver similar PCE values (18% vs 19.3% in direct comparison experiments) to additionally demonstrate improved ambient stability. [20] Typically, CuSCN is dissolved in organic sulfides (such as dimethyl-or diethylsulfide) for applying in perovskite solar cells; however, to obtain an electrospinnable solution with desired viscosity, small amounts of polymeric aid, polyethylene oxide (PEO) dissolved in pyridine, were added that resulted in the formation of CuSCN fibers. The [Cu(SCN)(NC 5 H 5 ) 1 or 2 ] complexes were transformed to phase-pure rhombohedral CuSCN (Figure 2b) after electrospinning followed by the calcination of as-spun fibers at 135 C for 24 h. [21] The fibers exhibited an average diameter of 427 AE 53 nm (n ¼ 50) and appeared to be brittle on a microscale, although the as-obtained fiber mat was sufficiently flexible (Figure 2a).…”

Solution-Processed Smooth Copper Thiocyanate Layer with Improved Hole Injection Ability for the Fabrication of Quantum Dot Light-Emitting Diodes

“…To avoid those drawbacks, we turn our attention to other materials exclusive of metal oxide HILs. After surveying the previous literature, we realize that copper thiocyanate (CuSCN) possesses several advantages and can act as a good HIL in optoelectronic devices, including high stability in an ambient atmosphere, high transparency in the whole visible range, moderate hole mobility of 0.01–0.1 cm 2 V −1 s −1 , and deep valence band level ( E VB ) around 5.3 eV [ 17 , 34 ]. CuSCN has been utilized in perovskite solar cells, thin film transistors, QLEDs, and OLEDs [ 17 , 20 , 33 , 34 , 35 , 36 ], and can be deposited into thin films by the solution process with a low-temperature drying.…”

“…After surveying the previous literature, we realize that copper thiocyanate (CuSCN) possesses several advantages and can act as a good HIL in optoelectronic devices, including high stability in an ambient atmosphere, high transparency in the whole visible range, moderate hole mobility of 0.01–0.1 cm 2 V −1 s −1 , and deep valence band level ( E VB ) around 5.3 eV [ 17 , 34 ]. CuSCN has been utilized in perovskite solar cells, thin film transistors, QLEDs, and OLEDs [ 17 , 20 , 33 , 34 , 35 , 36 ], and can be deposited into thin films by the solution process with a low-temperature drying. In this research, we adopt CuSCN as the HIL for the fabrication of QLEDs, and a strong electron-withdrawing molecule 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) was introduced to further improve hole mobility of CuSCN by p -type doping.…”