Current Status and Future Prospects of Copper Oxide Heterojunction Solar Cells

Abstract

The current state of thin film heterojunction solar cells based on cuprous oxide (Cu2O), cupric oxide (CuO) and copper (III) oxide (Cu4O3) is reviewed. These p-type semiconducting oxides prepared by Cu oxidation, sputtering or electrochemical deposition are non-toxic, sustainable photovoltaic materials with application potential for solar electricity. However, defects at the copper oxide heterojunction and film quality are still major constraining factors for achieving high power conversion efficiency, η. Amongst the Cu2O heterojunction devices, a maximum η of 6.1% has been obtained by using pulsed laser deposition (PLD) of AlxGa1−xO onto thermal Cu2O doped with Na. The performance of CuO/n-Si heterojunction solar cells formed by magnetron sputtering of CuO is presently limited by both native oxide and Cu rich copper oxide layers at the heterointerface. These interfacial layers can be reduced by using a two-step sputtering process. A high η of 2.88% for CuO heterojunction solar cells has been achieved by incorporation of mixed phase CuO/Cu2O nanopowder. CuO/Cu2O heterojunction solar cells fabricated by electrodeposition and electrochemical doping has a maximum efficiency of 0.64% after surface defect passivation and annealing. Finally, early stage study of Cu4O3/GaN deposited on sapphire substrate has shown a photovoltaic effect and an η of ~10−2%.

Nanostructured Cu2O Synthesized via Bipolar Electrochemistry

“…Analysis of Bode-phase plots (Figure 6a) was exploited to calculate the charge recombination time in dark and illuminated conditions. By evaluating the maximum peak frequency, the recombination times can be calculated using Equation (6).…”

“…While promising as a semiconductor, the major shortcoming that restricts the application of Cu 2 O in photovoltaics is its photochemical instability [3,4]. Numerous studies have been devoted to improving the stability of Cu 2 O electrodes in solution through surface modification with conducting polymers, metals, and oxides [5][6][7]. These protective layers not only inhibit photo-corrosion of Cu 2 O, but also facilitate the band structure for improved charge transport [6].…”

“…Numerous studies have been devoted to improving the stability of Cu 2 O electrodes in solution through surface modification with conducting polymers, metals, and oxides [5][6][7]. These protective layers not only inhibit photo-corrosion of Cu 2 O, but also facilitate the band structure for improved charge transport [6]. Despite the highlighted issue, Cu 2 O remains a thoroughly researched semiconductor material due mainly to the distinct qualities and characteristics that set it apart.…”

Nanoengineered Advanced Materials for Enabling Hydrogen Economy: Functionalized Graphene–Incorporated Cupric Oxide Catalyst for Efficient Solar Hydrogen Production

“…However, p‐type metal oxides are less studied for photocathode application. Copper oxide ideally fulfills the key requirements of photocatalyst; such as high optical absorption coefficient, earth abundant material, and can be easily processed for photocathode synthesis . Among different phases of copper oxides; cupric oxide (CuO) has relatively better photoconversion efficiency, however, it easily converts into cuprous oxide (Cu 2 O) resulting in an unstable photocathode .…”

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, [1][2][3][4] as photocathode in the solar-driven conversion to H 2 , [5][6][7][8][9] or for the catalytic CO 2 reduction to other useful products. [10][11][12] Its band gap of 2.1 eV renders the material interesting as solar absorber in singlejunction (record efficiencies up to 8.1% [13] ) and in tandem photovoltaic devices, [14,15] or as hole transport layer, especially in perovskite solar cells.…”