Low-Temperature Aqueous Ammonia-Processed Copper (I) Selenocyanate Hole-Transporting Material for Efficient Inverted Perovskite Solar Cells

Abstract

Significant efforts have been reported on copper­(I) thiocyanate (CuSCN) as an efficient hole-transporting layer (HTL) for perovskite solar cells. Surprisingly, its higher chalcogen analogue copper (I) selenocyanate (CuSeCN) is unexplored yet, even though CuSeCN has been shown to have different properties compared to CuSCN because of its different electronegativity, polarizability, and size (Se vs S atoms). In this work, we report the synthesis of CuSeCN as an HTL in perovskite solar cells via low-temperature solution-processable deposition from an aqueous ammonia solution. The transparency and thermal stability of CuSeCN films were examined by the deposition of thin films from an aqueous ammonia solution under ambient conditions. The structural, electrical, optical, and morphological properties of the CuSeCN films were characterized by X-ray diffraction, XPS, FTIR, cyclic voltammetry, UV–vis–NIR spectroscopy, and field emission scanning electron microscopy. A single-step fast deposition–crystallization method was used to fabricate low-temperature CuSeCN-based inverted planar perovskite solar cells, with device architecture indium tin oxide (ITO)/CuSeCN/CH3NH3PbI3/PC61BM/BCP/Ag. Furthermore, to examine the effect of the thickness of the HTL on device performance, three different concentrations of CuSeCN solution were used for thin-film deposition in perovskite solar cells. The annealing temperature of the HTL films was optimized to obtain the highest possible device performance. A maximum power conversion efficiency (PCE) of 13.59% (V oc = 0.99 V, J sc = 18.8 mA/cm2, and FF = 0.73) was achieved with 7.5 mg mL–1 of CuSeCN solution, along with negligible J–V hysteresis and reproducibility of device performance.

Enhancing the Efficiency and Stability of Perovskite Solar Cells through Gradient Energy Band Tin Oxide Electron Transport Layer Design with Graphene Quantum Dot Incorporation

“…As demonstrated in Figure e, the deposition of both SnO 2 and GQD/SnO 2 ETL on the ITO substrate exhibits a negligible impact on transmittance. Across all samples, the transmittance remains high across wavelengths, signifying that the addition of a small quantity of GQDs does not compromise the substrate’s transmittance . This advantageous attribute preserves device performance as lower transmittance equates to reduced light absorption by the perovskite layer, resulting in a substantial decline in device efficiency.…”

Thermally deposited copper(i) thiocyanate thin film: an efficient and sustainable approach for the hole transport layer in perovskite solar cells

“…In general, hole transport materials (HTMs) can be categorized into organic and inorganic materials. Compared with organic HTMs [such as 2,2′,7,7′-tetrakis[ N , N -di(4-methoxyphenyl)amine]-9,9′-spirobifluorene (spiro-OMeTAD), 12 (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), 13,14 poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 15 triphenylamine (TPA), spiro-OMeTAD derivatives and others], 16–19 inorganic HTMs [such as copper oxides (CuO X ), nickel oxides (NiO X ), 20 copper iodide (CuI), 21,22 copper thiocyanate (CuSCN), 23–26 and copper selenocyanate (CuSeCN) 27–29 ] exhibit excellent chemical stability, high hole mobility, and high optical transparency. 30,31 Moreover, the facile and low-cost preparation of inorganic HTMs has emerged as a cost-effective substitute for organic HTMs which have low transparency, high cost and usually a difficult synthetic route.…”

Insight into Controlled Surface Passivation of PEDOT:PSS for Defect Density Modulation and Efficient Charge Transport for Perovskite Solar Cells

“…In recent years, single-junction lead halide perovskite solar cells (PSCs) − have shown rapid improvement in their power conversion efficiency (PCE), − exceeding values of 25% . PSCs have become the most discussed photovoltaic technology during these years, attracting huge attention due to their various applications, low cost, and high performance in next-generation photovoltaics. − The unique optical, electronic, and physical properties of lead halide perovskites and optimization in device architecture with suitable stoichiometry and choice of appropriate materials for the hole transport layer (HTL) − and an electron transport layer (ETL) , are the main aspects for the rapid growth of PSCs. Despite the exceptional growth in the field, more improvement is required to achieve higher PCE and cost-effective commercialization , of the PSC technology.…”