Ultrathin Cu₂O as an efficient inorganic hole transporting material for perovskite solar cells

Abstract

We demonstrate that ultrathin P-type Cu2O thin films fabricated by a facile thermal oxidation method can serve as a promising hole-transporting material in perovskite solar cells. Following a two-step method, inorganic-organic hybrid perovskite solar cells were fabricated and a power conversion efficiency of 11.0% was achieved. We find that the thickness and properties of Cu2O layers must be precisely tuned in order to achieve the optimal solar cell performance. The good performance of such perovskite solar cells can be attributed to the unique properties of ultrathin Cu2O, including high hole mobility, good energy level alignment with CH3NH3PbI3, and longer lifetime of photo-excited carriers. Combining merits of low cost, facile synthesis, and high device performance, ultrathin Cu2O films fabricated via thermal oxidation hold promise for facilitating the developments of industrial-scale perovskite solar cells.

Metal Oxides as Efficient Charge Transporters in Perovskite Solar Cells

“…[199] In one representative work, Zuo et al developed a novel and facile method of preparing Cu 2 O and CuO films from CuI and employed the resulting films as HTMs in PSCs. [200] In a recent work by Rao et al, an efficiency of 19% was achieved by employing low-temperature-processed CuO x as the HTM. In addition, the PCE of the Cu 2 O-based PSCs remained stable at above 90% of its initial value even after 70 days.…”

“…Reproduced with permission [200]. b) PV performances of solar cells with different Cu 2 O layer thicknesses.…”

A 19.0% efficiency achieved in CuOx-based inverted CH3NH3PbI3−xClx solar cells by an effective Cl doping method

“…CuI was first reported to substitute spiro-OMeTAD in the traditional PSCs, showing a PCE of 6% [15]. Cu 2 O and CuO were also introduced as hole-transporting materials (HTMs) in the inverted PSCs with respective PCEs of 11.0% [18] or 13.4% [19] and 12.2% [19].…”

“…For further cost-effective application, the low-cost, simply prepared and stable inorganic hole conductors [15][16][17][18][19][20][21][22][23][24][25] have been applied as promising alternatives to the costly organic hole conductors, such as CuI [15,16], CuS [17], CuO x [18][19][20], CuSCN [21], NiO x [22][23][24][25]. CuI was first reported to substitute spiro-OMeTAD in the traditional PSCs, showing a PCE of 6% [15].…”

Aqueous Spray Pyrolysis of Cu2O Films: Influence of Reducing Agent and Acetic Acid Addition

“…Cuprous oxide (Cu 2 O) is an abundant and low‐cost p‐type semiconductor for sustainable energy production through the photovoltaic energy‐conversion, as photocathode in the solar‐driven conversion to H 2 , or for the catalytic CO 2 reduction to other useful products . Its band gap of 2.1 eV renders the material interesting as solar absorber in single‐junction (record efficiencies up to 8.1%) and in tandem photovoltaic devices, or as hole transport layer, especially in perovskite solar cells . Depending on the device application and desired Cu 2 O film properties, several physical and chemical deposition methods have been established.…”